Jeff

Aug 092018
 

It’s been an incredibly hectic week on all fronts, and I feel like I’ve been sprinting to keep up!

The new Soundsmith Zephyr Mk III phonograph cartridge.

I’ve been writing up my listening impressions for the Positive Feedback review of the new Soundsmith Zephyr Mk III phonograph cartridge from Peter Ledermann, and you should see that review published in the next week or two. Another great cartridge by Peter Ledermann!

Still Audio EL84 integrated amplifier.

I’ve migrated the artisanal Still Audio EL84 integrated amplifier into my Altec A5 Voice of the Theatre based system, and it’s a nice match and sounding mighty fine!

Altec A5 Voice of the Theatre system with Still Audio EL84 integrated amplifier.

The Still Audio EL84 integrated amplifier is next in my review queue after I finish up the review of the new Soundsmith Zephyr Mk III phonograph cartridge.

The Still Audio EL84 integrated amplifier is one fine artisanal amplifier at a very fair price!

This was quite an eventful week on the guitar front.

Friends John LaChapelle (left) & Larry Coryell (right) playing jazz. Photo by Dr. Kannan Krishnaswami.

Joan LaChapelle – wife of John LaChapelle, a legendary Pacific Northwest jazz guitarist, who is sadly no longer with us – recommended David Gitlen to me for continuing my studies in jazz guitar.

The photo below is of me, John LaChapelle, and Larry Coryell after their concert some years ago.

Left to right: Jeff, John LaChapelle, and Larry Coryell. It was a real treat meeting Larry after the concert!

As you might imagine, Joan’s bar is very high when it comes to jazz guitarists, and she really knows her stuff, so I contacted David after Joan’s recommendation to find out if he had an opening for a new student.

David took me on as a student! I had my first lesson on Tuesday with David, and I’m really, really, excited to be studying jazz guitar again.

David trained under Joe Pass and Jim Hall and is an amazing jazz guitarist, and I feel incredibly fortunate to be studying with him.

David pretty much blew me away playing “Satin Doll” by Duke Ellington, and made it look so easy (it’s not!).

See Joe Pass playing “Satin Doll” in the YouTube clip below.

In my own feeble but diligent way I’m working hard at improving my jazz guitar playing. I’ve been practicing “Satin Doll” this week, as well as learning all kinds of new stuff from David, and loving it!

When David saw my Collings he asked me if I just bought it, and I told him that I just bought it from Joe in Seattle at Archtop.com.

David laughed and told me that he saw the Collings on Joe’s website. David and his wife were vacationing in Ellensburg over the weekend, and they were going to drive over to Seattle to check out the Collings when Joe opened on Monday, and buy it if he liked it. But then David saw that it was sold – I beat him to it by a few days – we both laughed about it!

David really liked the Collings and made it sing playing “Satin Doll”!

Collings Eastside LC Deluxe and Fender ’65 Princeton Reverb

I had a terrific day today with my buddy Ron Barbee and his wife Sumi. Guitars, guitar amps, audio, music, and Sumi fixed us an absolutely amazing lunch that was a celebration of wonderful flavors – thank you so much for such a great day, Ron & Sumi! I felt like I was taking part in a wonderful celebration of life & music, and the time went by so fast!

You’ve read about Ron before here at Jeff’s Place, and he is an amazing talent both in audio and the guitar.

My buddy Doc Leo loaned me his Eico HF-81 so I could give it a listen, but when I hooked it up to my Altec 832A Corona’s and powered it up it gave me a nasty shock as my arm brushed against it.

It’s always a bit of a thrill when you feel AC going through your body, so I shut it off real quick and lived to tell about it.

Ron tells me that happens with those old Eico’s occasionally, and he’s going to take a look at it to see what’s going on with it.

Vintage Eico HF-81 EL84 integrated amplifier sitting atop vintage Altec 832A Corona loudspeaker.

When I first got the ’65 Fender Princeton Reverb it sounded a little rough, but it really smoothed out and got sounding really good as it got some more run-in time on it.

Ron and I pulled apart my ’65 Fender Princeton Reverb guitar amp to take a look inside at the tube complement, and it turns out that all the tubes in it are Russian tubes produced for Groove Tube, and they actually sound really good. I don’t know what Russian brand they are … maybe Sovtek’s? 

Ron had a nice selection of vintage 12AX7 tubes: Telefunken’s, Sylvania’s, Mullard’s, and others. We listened to the Fender with the stock tube, a Sylvania, and a Mullard, in V1 position.

It turned out that all three of them sounded really nice in the Fender, and Ron advised me to run the stock tubes until they start getting ragged and then replace them all with some nice NOS tubes.

The Sylvania 12AX7WA was a mellow and laid back sounding tube overall, but still had a lot of clarity in 1st through 3rd strings, with a really smooth presentation in the bass strings, but perhaps a little too smooth in combination with the CannaRex speaker.

The Mullard 12AX7 had rich textured tones in the bass strings, and a pure bell-like presentation in the treble strings. I liked it a lot.

The real surprise was the stock Russian Groove Tube 12AX7, which was kind of in between the Sylvania and Mullard in voicing, but was hard to fault for its jazzy tone. I liked it a lot too.

I’m going to take Ron’s advice and just hang with the stock tubes until they need changing, then I’ll round up some nice NOS tube choices to replace them.

Mom with a Glen Miller and his orchestra album!

Unfortunately, I’ve got some bad news to share. My Mom’s recent CT scan showed lung cancer that has spread to both lungs, accompanied by enlarged lymph nodes. Not operable, and probably not treatable. She’s never been a smoker so it was a surprise.

Mom’s 93, and was very stoic about the news, and seems to be in relatively good spirits, but is not feeling all that great lately. Mom has elected not to treat it even if it were possible, as at age 93 she doesn’t want her remaining time to be miserable from treatments.

I think Mom’s handling the news better than I am. I support her in whatever she chooses to do, of course, but it’s a rough go, and I hope things go as good as possible for her.

As you might imagine, the pace of my audio writing may slow down a bit as I focus on my Mom and making sure things are as good for her as possible.

Anyways, all the best to you, and thanks for stopping by, and may the tone be with you!

 Posted by at 7:57 pm
Aug 032018
 

As I mentioned a couple of posts ago, I’ve been using a Henriksen Jazz Amp, but I decided to order a Fender ’65 Princeton Reverb vacuum tube guitar amp from Sweetwater to use with my Collings Eastside LC Deluxe jazz guitar.

Henriksen Jazz Amp

The Henriksen is a nice sounding solid-state guitar amp for jazz, but I’ve been wanting to get a vacuum tube guitar amp for a while, so I ordered the Fender ’65 Princeton Reverb 15-watt 1×12″ Tube Combo Amp in lacquered tweed, which has been getting rave reviews.

Henriksen Jazz Amp (left) and Fender ’65 Princeton Reverb (right)

The Fender ’65 Princeton Reverb 15-watt 1×12″ Tube Combo Amp in lacquered tweed is a special edition that Fender makes for Sweetwater, and in Sweetwater’s words:

“Fender used the beloved ’65 Princeton Reverb as a starting point, then they added a beautiful and vintage-style lacquered tweed covering that will transport you back to the great Fenders of the 1950s. The speaker has been beefed up to a 12″ Eminence Cannabis Rex for its blend of smoothness and sparkle.”

One of the things I like about the Fender ’65 Princeton Reverb is its tube amp, which instead of having solid-state rectification like some of the other Fender guitar amps, it has vacuum tube rectification which almost always sounds better to my ears. I suppose that’s my audio preferences coming through, but I think it matters.

The tube complement is three 12AX7’s and one 12AT7 in the preamp section, a pair of 6V6’s for power tubes, and a 5AR4 rectifier.

Collings Eastside LC Deluxe and Fender ’65 Princeton Reverb

It’s way too early in the Fender ’65 Princeton’s run-in period to make any real comments about its performance, but it was immediately obvious that it was much more evenly balanced across the strings than the Henriksen, which emphasizes the 6th and 5th string more (i.e. more emphasis on the bass strings). 

One thing I might mention is that guitar amplifiers respond to high-performance power cords in much the same way as high-performance audio equipment does. 

For example, both the Henriksen Jazz Amp and the Fender ’65 Princeton Reverb benefited considerably from the high-quality Acoustic Revive Power Reference AC cord that I’ve been using over their OEM AC power cords. 

Anyways, I’ll report back after I get some more run-in time on the Fender ’65 Princeton Reverb. 

As always, thanks for stopping by, and may the tone be with you!

 Posted by at 7:57 pm
Jul 312018
 

I’ve been agonizing about whether to do it or not, but I’ve decided to put my vintage McIntosh MC225 and vintage McIntosh MC240 stereo power amplifiers up for sale, as they’re not seeing much use of late.

I hate to leave such wonderful vintage McIntosh amplifiers sitting around when they could be making beautiful music for someone, and by purchasing them you’ll be helping me out as I consider another musical adventure here at Jeff’s Place.

I wanted to let readers of Jeff’s Place have first shot at them at a more affordable price before I advertise them more broadly.

My vintage McIntosh MC225.

Vintage MC225 stereo amp, nude.

The MC225 stereo amp was restored by Yves Beauvais (Vintage Vacuum Audio) so it’s in great shape operationally, and about 8/10 cosmetically. The price is $2795 USD. This has been sold to David in France – thanks, David!

Vintage McIntosh MC240 stereo amplifier.

My vintage MC240 stereo amplifier is in “showroom” condition. I purchased it from Tom Manley (McIntosh Home Audio) and it was restored by Terry DeWick. The price is $3495 USD. This has been sold to Andrew in the USA – thanks, Andrew!

These are really wonderfully musical vintage McIntosh stereo amplifiers from the Golden Age of Audio, and I think you’ll enjoy them as much as I have. I wrote an article for Positive Feedback about them that you can read HERE.

The price is firm and they are good buys. I accept wire transfer for payment. Buyer pays shipping. Once the payment is received in my account I will ship them out. I don’t have the shipping weights for them yet, as I need to box them up, but soon as I do I’ll add the shipping weight.

If you think you might be interested you probably shouldn’t wait too long to decide, as items I put up for sale generally sell pretty quick. Just fair warning.

You can email me HERE if you are interested.

As always, thanks for stopping by, and may the tone be with you!

 Posted by at 9:22 am
Jul 292018
 

I’m working on Part 2 of my Soundsmith review series for Positive Feedback right now, the Zephyr Mk III phonograph cartridge, and hope to have it published in the next few weeks.

The new Soundsmith Zephyr Mk III phonograph cartridge on the CTC Classic 301.

In my Part 1 Soundsmith review for Positive Feedback I reviewed the Soundsmith Carmen Mk II phonograph cartridge (HERE).

I found the Carmen Mk II to be a warm, dimensional, and wonderfully musical phonograph cartridge that at $1000 USD is hard to beat for my tastes.

Interestingly, the Carmen Mk II on my Schick 12-inch tonearm matched the performance of my beloved Ortofon SPU Classic GM MkII phono cartridge mounted on the Woody 12.5-inch SPU tonearm in nearly identical musical & sonic fashion, with the added bonus that the Carmen Mk II doesn’t require an expensive step-up transformer like the Ortofon does to make it usable in my Westminster-based audio system.

I’ve never had that improbable result happen before where the combination of two different phonograph cartridges on two different tonearms sounded so similar in musical and sonic terms.  It made me smile, and I really enjoyed the result!

Vintage Altec Corona 832A loudspeakers with Spec RSP-AZ9EX Real Sound Processors

My love affair with my vintage Altec Corona 832A loudspeakers continues, and I’m still amazed at how musical they sound tucked into the room corners of my bedroom system. In fact, I’m listening to them now as I write from my living room, and I’m marveling at how effortlessly and naturally they fill the whole house with beautiful music. If I had to move into a smaller apartment where I could only have one pair of loudspeakers, the Corona 832A’s are the ones that would go with me.

Spec RSP-AZ9EX Real Sound Processors

I haven’t touched the Spec RSP-AZ9EX Real Sound Processors (impedance compensators) that Yazaki-san sent me, which he optimized for my 16 Ohm Altec Corona 832A’s, since I installed them. They sound great!

I attached them to the binding posts of my Corona’s with some vintage Western Electric WE16GA wire, as Yazaki-san would, I suppose.

As I understand it, the Spec RSP-AZ9EX Real Sound Processors are essentially a Zobel network circuit – a series resistor-capacitor network that is connected in parallel with a loudspeaker driver – installed into a beautifully crafted wood chassis incorporating quality binding posts, so you can attach them via lengths of wire to your loudspeakers’ binding posts.

The Spec RSP-901EX Real Sound Processors that I’ve previously reported on (above) were designed with 8 Ohm loudspeakers in mind, but the AZ9EX’s that Yazaki-san sent me were optimized for the 16 Ohm load of the Altec Corona 832A loudspeakers.

When you optimize an impedance compensation circuit for a particular loudspeaker, you have to take into account the DC resistance and voice coil inductance of the driver in order to determine the values the resistor and capacitor used in the impedance compensation circuit. You can get an idea of how this works by experimenting with values in the Zobel circuit calculator HERE.

What quickly becomes apparent is that the values of the capacitors used for 8 Ohm drivers and 16 Ohm drivers would be very different, so you couldn’t expect the Spec RSP-901EX Real Sound Processors (for 8 Ohms) to be a happy match for 16 Ohm Altec’s like my Corona’s (or my A5’s or A7’s).

Care package from Yazaki-san with custom RSP-AZ9EX’s for the Corona’s!

I’ve got some questions into Yazaki-san requesting he expand upon his thought process for optimizing the AZ9EX’s for a 16 Ohm load like my Altec’s, whether or not the new Spec RSP-AZ9EX Real Sound Processors will be available in both 16 Ohm and 8 Ohm versions, pricing, etc. Knowing Yazaki-san it will be a very interesting read!

SPEC RSA-M3 EX Real Sound Amplifier.

Speaking of Spec, I’ve been using the superb Spec RSA-M3 EX Real Sound Integrated Amplifier with my vintage Altec A7 Voice of the Theatre loudspeakers that were made by Altec for Leopold Stokowski’s home use when he lived in New York, which are essentially full-sized Altec A7 Voice of the Theatre loudspeakers wrapped in big custom cabinets to be more attractive for home use.

The Spec RSA-M3 EX Real Sound Integrated Amplifier is a superb match to the Altec’s, and has inspired more than one visiting listener as to the potential of vintage Altec loudspeakers.

Leopold Stokowski’s Altec A7’s were a nice addition to my vintage Altec loudspeaker “stable”.

When I get started on the Duelund-Altec crossover project with the vintage “Stokowski” Altec A7’s my plan is to migrate the Spec RSA-M3 EX Real Sound Integrated Amplifier to my Altec 832A Corona-based system, which I suspect will really complement the Corona’s, so I am really looking forward to hearing that Spec & Altec 832A Corona combination – more to come!

I’ve got the new exotic and expensive Acoustic Revive Absolute Power Cords and RCA Absolute FM Interconnects getting some run-in time in various systems, and they’re sounding really nice.

Acoustic Revive RTP-6 Absolute.

I’ve got an Acoustic Revive Absolute Power Cord connecting the Acoustic Revive RTP-6 Absolute NCF Power Distributor to my wall AC, which powers my entire Westminster-based system.

The Absolute Power Cord is sounding mighty good, and surprisingly different from the Acoustic Revive Power Reference TripleC NCF AC power cords I reviewed HERE, which are essentially the same power cords with the exception of the addition of the Degawa method MD unit around the midpoint of the power cord.

Acoustic Revive Absolute Power Cord and RCA Absolute FM Interconnects.

I’ve got an Absolute Power Cord and pair of RCA Absolute FM Interconnects getting some run-in time in my vintage Altec 832A Corona-based system on the Mhdt Paradisea+ USB DAC. I know, it’s a crazy combination from a price perspective, but it sure is a great way to enjoy the Absolute Power Cord and pair of RCA Absolute FM Interconnects while they’re getting some run-in time, and do they ever make the Corona-based system sound great!

Altec A5 Voice of the Theatre loudspeakers with Still Audio EL84 integrated amplifier.

I’ve also got an Absolute Power Cord and pair of RCA Absolute FM Interconnects getting some run-in time in my Altec A5 Voice of the Theatre based audio-visual system.

The Absolute Power Cord is powering the Still Audio EL84 integrated amplifier to excellent effect, and with the RCA Absolute FM Interconnects connecting the Leben RS-30EQ phono equalizer to the Still Audio EL84 integrated amplifier.

Speaking of the Still Audio EL84, as soon as I’m finished writing up the Soundsmith Zephyr Mk III review for Positive Feedback, I’ll be starting on the Still Audio EL84 review for Positive Feedback.

As you would expect, the 10 watt per channel Still Audio EL84 has more than enough power to drive the Altec A5 Voice of the Theatre loudspeakers to live-like levels.

The Still Audio EL84 integrated amplifier is warmer and richer sounding than the Leben CS-600 integrated amplifier that normally resides in the system, which is not something you would normally associate with EL84 amplifiers.

The Still Audio EL84 integrated amplifier is not your typical EL84 amplifier which is often built to be a budget unit, as the Still Audio EL84 is more of a tour de force example of how good an EL84 based amplifier can be. More to come!

First Watt SIT-3 power amplifier.

The First Watt SIT-3 stereo amplifier review is now live at Positive Feedback HERE. After the conclusion of the review Nelson sent me an email saying:

“Since you are tuned into tubes, perhaps you would like to hear a little preamp I cobbled together using the Korg (Noritake) Nutube, which is a tiny little pc mount triode. It does a very good job with the 2nd harmonic and has cute little glowing cathodes.”

I let Nelson know I would enjoy giving his Nutube preamp a listen, so stay tuned on that topic as I find out more about timing and such. More to come!

Fender ’65 Princeton Reverb 15-watt 1×12″ Tube Combo Amp in Lacquered Tweed.

I’ve been using a Henriksen Jazz Amp for a number of years, but I decided to order a Fender ’65 Princeton Reverb vacuum tube guitar amp from Sweetwater to use with my Collings Eastside LC Deluxe jazz guitar.

Left: Collings OM2C acoustic guitar for fingerstyle playing. Right: Collings Eastside LC Deluxe jazz guitar.

The “Fender ’65 Princeton Reverb 15-watt 1×12″ Tube Combo Amp in Lacquered Tweed” is a special edition that Fender makes for Sweetwater, and in Sweetwater’s words:

“Fender used the beloved ’65 Princeton Reverb as a starting point, then they added a beautiful and vintage-style lacquered tweed covering that will transport you back to the great Fenders of the 1950s. The speaker has been beefed up to a 12″ Eminence Cannabis Rex for its blend of smoothness and sparkle.”

The main difference between a standard Fender ’65 Reverb and this amp is that the standard version uses a 10-inch speaker and this one uses the 12-inch Eminence Cannabis Rex speaker, and it’s wrapped up in lacquered tweed for a vintage look.

One of the things I like about the Fender ’65 Princeton Reverb is its tube amp, which instead of having solid-state rectification like some of the other Fender guitar amps, it has vacuum tube rectification which almost always sounds better to my ears. I suppose that’s my audio preferences coming through, but I think it matters.

The tube complement is three 12AX7’s and one 12AT7 in the preamp section, a pair of 6V6’s for power tubes, and a 5AR4 rectifier.

Ok, that’s it for now. As always, thanks for stopping by, and may the tone be with you!

 Posted by at 1:13 pm
Jul 262018
 

I’ve always loved jazz guitar.

John La Chapelle & Larry Coryell having fun playing music together.

One of the highlights in my life was being able to study with the extraordinary jazz guitarist, John La Chapelle (above left), who was Larry Coryell’s guitar teacher when he was a youngster and introduced him to jazz, and the two maintained their friendship over the years.

Left to right: Jeff, John, and Larry. It was a real treat meeting Larry after the concert!

Jazz guitar is perhaps the most difficult to learn well of the guitar styles I enjoy, and I wish I had more time learning with John, but my time with him was cut short when he became ill, and then subsequently passed away.

As a result, I got a glimpse into what it means to play jazz competently on the guitar, but didn’t get there myself, so one of my goals now that I’m retired is to learn to play the guitar better.

There’s four kinds of guitar playing I really enjoy listening to and want to get better at: jazz chord melody and improvisation, fingerstyle arrangements, as well as classic rock or blues (think CSNY, or Clapton, McCartney, or Young Unplugged).

Collings short scale OM cutaway.

It really helps to have the right tools for what you’re doing, and I’m pretty well equipped for fingerstyle guitar with my short scale Collings OM2C (above), which is a beautiful sounding and playing guitar.

For acoustic blues my Waterloo (by Collings) WL-14L is a wonderful guitar (below left). Mine’s got the optional ladder-bracing and carbon fiber T-bar, and it is an extremely light, comfortable, and responsive guitar to play.

Collings Waterloo WL-14L (left) and Gibson Advanced Jumbo (right).

I really have been wanting a smaller and more comfy to hold jazz-focused guitar, and I noticed that Joe Vinikow (Archtop.com, in Seattle) had a used Collings Eastside LC Deluxe archtop guitar for sale on his website (below), so I made an appointment with Joe to take a look at it.

Photo by Joe Vinikow

The Collings Eastside LC Deluxe archtop guitar utilizes a single Lollar Charlie Christian pickup (the Charlie Christian is by far my favorite style of jazz guitar pickup), and it was designed to have vintage tone for the professional jazz player (with attention to detail like using a DiMarzio 500K pot with a Jupiter Vintage Yellow cap, for example).

I’ve been agonizing about whether or not to keep my Adirondack Spruce and Brazilian Rosewood Gibson Advanced Jumbo (above right), as I wasn’t playing it much, but it was such a beautiful and great sounding guitar that I was loathe to let it go.

Gibson Custom Shop “Luthier’s Choice” Advanced Jumbo, Brazilian rosewood back & sides, Adirondack spruce top, Waverly tuners, 2001.

After agonizing about it, I decided I would trade my Gibson AJ (above) in on the Collings if it played well, which I figured it probably did, as Collings is known for their quality construction and setup.

Larrivee Model P-09 Rosewood Parlor with fossil ivory bridge pins.

I also decided to consign a couple of other guitars that I had, my mint Larrivee Model P-09 Rosewood Parlor guitar (above), and my mint Eastman Uptown AR910CE Archtop guitar (below).

Eastman Uptown AR910CE Archtop

I am the original owner of all of these guitars, and if you think you might be interested in one of them I’m giving you advance warning, as they will be appearing on Archtop.com for sale in the near future. If you think you want one you can reserve it early by sending Joe an email HERE.

Joe’s place, Archtop.com, in Seattle.

I had done an all-nighter the night before so I was really beat, but made to the road trip to Joe’s yesterday morning to look at and try out the Collings Eastside LC Deluxe he had for sale, which was on consignment from a pro player in LA.

Joe’s place, Archtop.com, in Seattle.

Joe has a beautiful selection of guitars, and many of them are consignments from pro players around the world who only trust Joe to get them sold to a deserving client looking for a nice guitar.

Joe’s place, Archtop.com, in Seattle.

Joe’s store is a lot of fun, with more amazing guitars than you can imagine, like the beautiful selection of Selmer-Maccaferri style of guitars above. Just a heads up, Joe had a number of beautiful guitars by Shelly Park, if you want to avoid the long waiting list this is your chance.

Joe’s place, Archtop.com, in Seattle.

New guitars are coming in all the time at Joe’s, and only a fraction of them are up on his website at any given time due to it taking time to get them all checked out and listed, so if you are looking for something in particular, you can contact Joe and find out what he has that hasn’t been listed yet.

Collings Eastside LC Deluxe archtop guitar.

I was so tired from doing an all-nighter plus the long drive to Seattle I could barely see straight, but I got a chance to play the Collings Eastside LC Deluxe archtop guitar. It only took a few seconds to determine the Collings was in great shape and played beautifully, so I bought it.

I also got a chance to briefly play a number of the other guitars at Joe’s while he was writing up the sale … the stuff of dreams … before turning around and making the long drive home.

I was so tired driving home I made a couple of stops to get out and walk around a bit to stay alert, and then when I got home I immediately took a couple hour nap and called it an early night.

Next time I do a road trip I plan to make it more leisurely, but I have a time crunch going on right now, so this one was compressed time-wise.

I’m back home now and have lots to do on the audio front, but this morning I’m focusing on a little guitar playing!

I just had the sudden inspiration that I should investigate having BTPA make me a custom guitar cord out of Belden 8402.

Update: I contacted BTPA and placed the order, and they’re making one up for me with Neutrik connectors. I let you know how it turns out!

As always, thanks for stopping by, and may the tone be with you!

 Posted by at 8:23 am
Jul 192018
 

My review of the First Watt SIT-3 is now live at Positive Feedback HERE.

First Watt SIT-3 power amplifier.

Within its areas of strengths (and power limitations) the First Watt SIT-3 is one of the best, if not the best, amplifier I’ve ever heard.

If you think you might want a First Watt SIT-3 of your own don’t wait too long to decide, as only 250 of them will be built and offered for sale.

I would like to thank Nelson Pass for the opportunity of writing about the First Watt SIT-3 for you here at Jeff’s Place and for Positive Feedback – thank you, Nelson!

As always, thanks for stopping by to read my articles, and may the tone be with you!

 Posted by at 11:01 am
Jul 142018
 

I’ve been wanting to write a “First Impressions” update about the Still Audio EL84 integrated amplifier for a while now, but life has been busier than anticipated, so I’m a little behind writing-wise.

Still Audio EL84 integrated amplifier powering my vintage Altec 832A Corona’s!

Many of you know of my affection for EL84 amplifiers, and I’ve been very impressed with the performance of the different ones I’ve listened to music with over the years, like the Almarro A205A single-ended pentode EL84 integrated amplifier, the Tom Evans Audio Design Linear A hybrid EL84 stereo amplifier, and the vintage Fisher SA-100 stereo amplifier, for a few examples.

There’s just a special magic that goes along with the EL84 pentode vacuum tube, whether it be in a triode circuit, a pentode circuit, or an ultra-linear circuit, like that of the Still Audio EL84 integrated amplifier.

I’m really impressed by what I’ve been hearing from Mark Still’s EL84 integrated amplifier powering my vintage Altec 832A Corona loudspeakers that I bought from LA Jazz Audio, shown in my living room in the photo above, but since moved into my bedroom system where they’ve really excelled placed into the room corners.

The room is too wide to get both Corona’s gracefully into a single single photo, so hopefully the two photos below will give you a better idea of speaker placement.

Vintage Eico HF-81 EL84 integrated amplifier hiding in the corner.

Almarro A205A EL84 single ended pentode amplifier hiding in the left corner.

Intrigued with the Still Audio EL84 integrated amplifier, I wanted to interview Mark Still and find out more about his design goals for the amplifier.

Mark told me:

“I started designing this amplifier in January 2017. I wanted to build an integrated type amp that would fit into spaces that most high end amplifiers wouldn’t. I also wanted it to have a good amount of power, more than a typical SET amplifier could deliver. I wanted to create something that didn’t currently exist and could win an industrial design award. It had to be a work of art and it had to be very high quality. The shape of the amp was of prime concern. I have always been a fan of amps that were long and thin like the Quad, some of the old Fisher’s, and others.  That is where the initial shape idea came from.  Some other aspects of the design were inspired by the late and great Don Garber.  What a great designer, he will be missed!”

“Modern day systems don’t require a lot of inputs, and a good majority of modern systems only use two inputs for a DAC and a phono stage, so that’s what I did, and provided two inputs. I wanted to keep it simple and easy, and to fit today’s systems needs. For outputs I chose to include 4 Ohm, 8 Ohm, and 16 Ohm outputs, because a lot of speakers favored by those with low-powered amplifiers are either 8 Ohm or 16 Ohm. There’s very few 4 Ohm loudspeakers out there, but I chose to offer all the modern speaker impedance options.”

Still Audio EL84 integrated amplifier by Mark Still.

I asked Mark to elaborate a little on his circuit design for the Still Audio EL 84 integrated amplifier:

“The input stage consists of a 12AU7 phase inverter. The 12AU7 was chosen because of its high current capabilities and can easily drive a pair of EL84’s to full output.  Because of this it’s a great tube for  phase inverter duties. The output stage consists of a pair of EL84’s pentodes connected in ultra-linear (UL) mode to the output transformer, and no negative feedback is applied.  This requires a very high quality transformer so Hashimoto transformers where chosen for the job.  Each channel is idling at ~81mA. Each of the EL84’s are cathode biased at ~39mA and the 12AU7 is ~3mA. This circuit can output ~10 Watts in UL operation. While the EL84 is capable of 15-20 watts the distortion goes up significantly when UL operation is not used.  I chose this mode because I wanted very low distortion. All of the tubes are running at or below spec so vintage tubes can be used without worry of burning them up and they all should last for a very long time.”

“The power supply uses a large 300mA transformer, into the 5AR4 rectifier tube that has output capability of 220+mA into the choke capable of 300mA. From there each channel is split off into it’s own set of low ESR reservoir caps to supply each channel. I chose to use “banks” of smaller caps, 47uF or 56uF, rather than a very large single cap because they are capable of filling faster with each mains cycle. There are no resistors in the power supply for the output stage. Only one to drop the voltage and separate the phase inverter that also has its own reservoir cap. This gives the power supply very low impedance contributing to the amplifiers speed and agility. The power supply can supply both channels at full output and run at about 50% giving it a good amount of head room.”

“The splitter/driver stage is a paraphase type. I chose it because it is simple, straight forward, and works from 5k to 100k very well. I’m a big Magnavox fan and they used the paraphase in many of their designs. I know the benefits of fixed bias, and you know it’s not that hard to adjust, but people today tend to shy away from amps they have to “mess with”. A lot of audiophiles don’t want to mess with adjusting the bias every few months, which is why I went with cathode bias. Each tube has its own cathode resister, precision 1% Mills. The tubes are AC heated as I think that DC heating make the amp sound too dull.”

The excellent sonics and musicality of the Still Audio EL84 also made me curious about the components Mark chose for it, so I asked Mark to tell me a little more about his components choices:

“I’ve always been a fan of Hashimoto transformers, and their frequency response charts are flat from 5Hz to over 100Hz, giving me a wide range to work with. My resistors of choice for this circuit are the Takman carbon film resistors, and they sounded better in my sound tests than the Kiwame and Amtrans resistors I tried. The bypass capacitors are Nichicon FG series (Fine Gold) audio caps and are fantastic caps for bypass caps. The coupling caps are Mundorf’s. They take a long time to break-in but have a very smooth sound with solid bass.”

“As far as tubes go, every tube type I tried sounded different. I think people should use the tubes that sound best to them for their audio system.  Psvane tubes with jazz are super sweet sounding, while the Sovtek EL84M’s are great for rock and roll, for example.  I chose the Mullard’s because they gave a nice balance that falls between the PSvane’s and Sovtek’s. Mullard was also smart in putting the labeling on the correct side of the tube. Most of the time pins 4-5 heaters are on the outside of the chassis, which puts the labeling in front for you to see. I wish other tube manufacturers would do the same.”

“The tube sockets are all PTFE with gold pins. The PTFE sockets hold the tube tighter, but they are softer than ceramic tubes sockets, so you have to be more careful not to the PTFE with the tube pins when changing tubes. If they get scratched it won’t affect the sound or the tightness, just the esthetics.”

“For the prototype I built on 3 turret boards so I could change out parts easily, but the time and effort to build it that way was not cost effective. I was very pleased when I did the first printed circuit board (PCB), where I used extra thick solid copper traces. The PCB tightened up the sound, and took it in the direction of being quieter and deeper. I’m thinking with the turrets for each component the signal had to go from component to turret to wire to turret to the next component, and with the PCB it was just component to copper to component, through one piece of thick solid copper. There is still a lot of point to point wiring, and I used silver over copper with PTFE insulation everywhere except from the IEC to power transformer, where I used 14 AWG copper.”

I also asked Mark about his voicing strategy for his integrated amplifier:

“I wanted to voice the amp to sound like a new-style tube amplifier, more of a clean sound, but with that tube magic. I wanted it to have finesse while maintaining a calm sensibility and listenable quality about it. If an amplifier is too bright it will sound amazing at first, but it will eventually annoy the listener. I wanted the bass to go as low and flat as I could get it without compromising the rest of the audio band.  I achieved an overall pleasurable listening experience, with great spatial image and a big wide and tall sound stage, so I feel I have succeeded in my voicing goals. As a reference I used a McIntosh MC275 power amplifier and C22 commemorative edition preamplifier. I have to say I’ve been pretty happy with the results.”

One of the features I love about the Still Audio EL84 integrated amplifier is the remote volume control, which is something I wish every integrated amplifier and preamplifier included.

“I designed my own remote control system. I originally went out looking for one but could not find anything even close to my needs. I had to have a remote  because I know people (including me) want that remote when the volume of this or that song needs to be just a little louder or quieter you can hit the button and get just what you want.  It’s pretty nice at the end of a long day.” 

“The remote is actually programmable to any remote but you would have to remove the bottom to push a small button on the remote board and watch the LED to program it. So easy though.  Push the button, then push the volume up button 4 times until it flashes, then push the down button 4 times until it flashes and you’re done – it’s  programmed to that remote.  In the future I may put a hole in the bottom to allow the button to be pushed without removing the bottom.”

At least for the moment, the sole source component in my vintage Altec Corona 832A loudspeaker-based audio system is my iMac streaming the fantastic Jazz24 stream through the Mhdt Paradisea+ USB DAC.

Mhdt Lab USB DAC sitting atop an Acoustic Revive isolation platform.

Getting some run-in time on the Still Audio EL84 are the new Acoustic Revive Absolute Power Cord and the new Acoustic Revive RCA Absolute FM Interconnects.

Acoustic Revive Absolute power cords and interconnects.

Speaker cable is Duelund DCA16GA tinned-copper wire, and a Locus Design Group Polestar USB interconnect links the iMac to the Mhdt Lab Paradisea+ USB DAC.

Sablon Audio Gran Corona power cord with special filter for digital, Polestar USB interconnect, and Acoustic Revive RCA Absolute FM interconnects.

Custom pair of Spec RSP-AZ9EX Real Sound Processors made by Yazaki-san.

On my vintage Altec 832A Corona loudspeakers I used the custom pair of Spec RSP-AZ9EX Real Sound Processors that Yazaki-san made for them – they make for a nice improvement! The RSP-AZ9EX Real Sound Processors are connected to my Corona’s with vintage Western Electric WE16GA tinned-copper wire.

Ok, now for some first listening impressions. First of all, the Still Audio EL84 integrated amplifier’s 10 watts per channel output sounds massively powerful on my vintage Altec Corona 832A loudspeakers, and I’m easily able to achieve live-like listening levels with it – that’s a important plus for musical enjoyment in my book.

The Still Audio EL84 integrated amplifier is much more evenly balanced bass-to-treble than my Almarro EL84 integrated amplifier. In fact I didn’t realize the full extent of the superb bass quality of my Altec Corona 832A loudspeakers until I put the Still Audio EL84 into the system, and its bass quality and quantity are at a significantly higher level of performance than the Almarro EL84.

The Still Audio EL84 integrated has a beautifully voiced mid-range and high-frequency presentation that is timbrally realistic, tonally beautiful, has a captivating level of naturally resolved nuance, and an overall musicality that makes it very rewarding to listen to to music with.

My vintage Altec Corona 832A loudspeakers are all about the tone and feeling in music, and they have an intensely musical presentation that I think most music lovers would “kill for” in their home audio system. The Still Audio EL84 amplifier really complements and enhances the Altec’s overall musicality, providing a truthful and engaging portrayal of beat, rhythm, melodies, harmonies, and dynamics.

My first listening impressions are very positive, with the Still Audio EL84 integrated amplifier providing a combination of musicality and sonics that I find very alluring, and all at a very fair $2895 USD considering the incredible parts quality and the hand-crafted artisanal nature of the amplifier.

Still Audio EL84 integrated amplifier with remote control.

Well that’s all for now. For my next listening impressions update I plan on listening to the Still Audio EL84 integrated amplifier in place of my Leben CS-600 integrated amplifier in my vintage Altec A5 Voice of the Theatre loudspeakers-based audio-visual system, which should be a lot of fun!

As always, thanks for stopping by, and may the tone be with you!

 Posted by at 11:21 am
Jul 132018
 

Today’s Fresh Catch are the exotic new Acoustic Revive Absolute Power Cords, RCA Absolute FM Interconnects, and PC-TripleC/EX Headshell Leads.

I always get excited when new Acoustic Revive products arrive from Mr. Ken Ishiguro (Acoustic Revive) via Mr. Yoshi Hontani (Muson Project, Exporter), as Acoustic Revive products always have an extreme level of quality materials, technical ingenuity, a  beautiful fit & finish, and with performance to match!

Ken Ishiguro is always researching how to create higher performing audio products by exploring exotic new approaches through advances materials science and technology, and through extreme attention to detail and quality.

The New Acoustic Revive Absolute Power Cords

The new Acoustic Revive Absolute Power Cable.

Let me tell you about the features of the new Acoustic Revive Absolute Power Cord, like the new “Degawa method MD unit”, which is the large cylinder you see in the photos surrounding the power cord.

The Degawa method MD unit.

The new Acoustic Revive Absolute Power Cord is similar to the Power Reference TripleC NCF AC power cords that I reviewed HERE, with the most obvious difference being the addition of the Degawa method MD unit that surrounds the cable at its mid-point.

Ken-san tells me the Degawa method MD unit is a magnetic thermal fluctuation noise suppressor.

You will see thermal fluctuations noise variously referred to as Johnson-Nyquist noise, Johnson noise, or Nyquist noise, after John B. Johnson at Bell Labs who first detected and measured it in 1926, and which was then later explained by Johnson’s colleague, Harry Nyquist.

Thermal fluctuation noise is generated as a result of thermal agitation of electrons as a function of resistance and temperature as current flows through a conductor in an electrical circuit. Thermal fluctuation noise is present in all circuits to one degree or another, and there has long been research into reducing it for improved circuit performance, particularly related to the ability to make the precision measurements needed for scientific research.

For example, in scientific research equipment passive magnetic shields are routinely used to create a region in space that is magnetically isolated from their surroundings to allow for more precise measurements by reducing thermal fluctuation noise, and essentially this is what the Degawa method MD unit does on the Acoustic Revive Absolute Power Cord.

Ken-san tells me that with the Degawa method MD unit consists of a “tunnel-like structure unit in which a plurality of specially shaped magnets are alternately combined, then this unit is covered with a blend of natural ore particles”.

The Degawa method MD unit encircles the power cord, and when AC power flows through the power cord into the magnetically isolated space created by the Degawa method MD unit the thermal magnetic noise is suppressed, resulting in lower noise being transmitted from the AC power line into the audio system circuits for an improvement in performance of the circuit.

It is my understanding that the Degawa method MD unit is in the initial stages of the patent process in Japan.

Another feature of the Acoustic Revive Absolute Power Cord is the PC-TripleC 2.8 x 2.4 mm oval single-wire conductors, the same conductors as used in the Power Reference TripleC NCF power cords that I reviewed last year.

Allow me to quote Ken-san from that review:

“The ideal cable is one that is not diminished by transmission loss or alteration. There are no cables that will improve sound quality, rather it is only by reducing transmission loss and transmission alteration that more of the original sound quality can come through.”

“In order to eliminate transmission loss and transmission alteration, Acoustic Revive jointly developed with various specialized material manufacturers the ideal cable structure.”

“In particular, we use a single core conductor of PC-TripleC in an elliptical shape, which excludes resonance inherent to a single wire, that is created for us by the world’s best forging manufacturing method by FCM Co., Ltd.” I might add the the PC-TripleC wire is oxygen free wire

“We jointly developed a flexible Teflon coated copper tube to use as a shield, which provides ease of handling with complete shielding characteristics. For inside the shield we collaborated with Eisai to develop a natural silk tube that we use to separate the conductors and suppress vibration by combining dissimilar materials.”

Additionally, Ken-san says that the Acoustic Revive Absolute Power Cord is “… equipped with a natural quartz layer which controls the electromagnetic waves during transmission and creates an organic and fresh sound with texture.”

The final layer is a protective sheath made of carbon SF tubing, whose purpose is to neutralize static electricity effects and to provide a double shielding effect for the power cord.

The conductors are terminated with the NCF(R) Piezo Ceramic Series of Furutech AC plugs, the FI-50M NCF(R) on the wall outlet end (above), and the FI-50 NCF(R) IEC plug for connecting to components (below).

Here’s what Furutech says about their FI-50 NCF Rhodium series of plugs:

“Furutech’s Pure Transmission FI-50 NCF Piezo Ceramic series connector bodies and housings feature several breakthrough construction techniques.”

“A multilayer nonmagnetic stainless steel and silver-plated carbon fiber shell incorporates a special damping and insulating acetal copolymer. Furutech settled on stainless and silver-plated carbon fiber for the outer housing after extensive listening sessions with Japanese industry figures and audiophiles.”

“The body of the connectors incorporates an “active” damping material: Nano Crystal² Formula—Nano Crystalline, Ceramic and Carbon Powder.”

“Incorporated into select Furutech products, Nano Crystal² Formula (NCF) is comprised of a special crystalline material that has two “active” properties. First, it generates negative ions that eliminate static and secondly, it converts thermal energy into far-infrared. Furutech then combines this remarkable crystalline material with nano-sized ceramic particles and carbon powder for their additional “Piezo Effect” damping properties. The resulting Nano Crystal Formula is the ultimate electrical and mechanical damping material – only found in Furutech products!”

“Nano Crystal Formula eliminates static, “interconverts” thermal, mechanical and electrical energy and damps vibrations – all for the finest Furutech Pure Transmission signal imaginable.”

“How far will Furutech’s engineers go in their attempts to reach Pure Transmission reference quality? Their concentrated examination of each and every element of signal transfer has resulted in another breakthrough technology, the Furutech Earth/Ground Jumper System. It eliminates EMI (Electromagnetic Interference) induced in metal parts like connector housing screws.”

“Current flowing through the power connector creates a magnetic field, just as an insulated conductor creates both electromagnetic and electrostatic fields. Furutech engineers found this magnetic field induces current flow (and a small magnetic field) in the screws holding the connector together! These magnetic fields interfere with the larger magnetic field around the conductor and connector.”

“Furutech’s total attention to detail and elegant engineering neatly solves the problem. The Earth/Ground Jumper System connects the securing screws to a ground terminal within the plug completely eliminating the field disturbances they cause. The stray fields are grounded by a series of interlocking parts within the connector that attach to the ground conductor. The Jumper System is available in Furutech NEMA Power and IEC Connectors. The Earth/Ground Jumper System Carries US Patent No. 6,669,491″

Essentially, the Furutech FI-50 NCF Rhodium power plugs are mini-components all by themselves, and are intended to be the power plug equivalents of the Sirens of Greek mythology, power plugs that lure in audiophiles with their enchanting musical voices and shipwreck our perceptions of what a power plug can do. Beware, if you listen to their Siren song your fate may be sealed!

Just one look & touch of the Furutech FI-50 NCF Rhodium power plugs pretty much awes me, they’re nice!

The PC-Triple C conductors are joined to the NCF(R) Piezo Ceramic Furutech AC plugs using a screw fastening method that Acoustic Revive developed with Matsukin Co., Ltd., which eliminates the sound quality degradation of solder.

I’ve got two of the Acoustic Revive Absolute Power Cords getting some run-in time in my Tannoy Westminster Royal SE-based audio system, with one on Nelson’s First Watt SIT-3 stereo amplifier that is in for review, and the second connecting the Acoustic Revive RPT-6 Absolute NCF Power Distributor to my wall outlet. A third Absolute Power Cord is getting some run-in time in my vintage Altec Corona 832A-based audio system.

The New Acoustic Revive RCA Absolute FM Interconnects

The Acoustic Revive RCA Absolute FM Interconnects utilize the new PC-Triple C/EX forged hybrid silver-copper conductors.

The new PC-Triple C/EX conductor is a unique affair, and in very simplistic terms it is 5N purity grade silver tubing with a 5N purity grade copper conductor running through its center. These silver/copper conductors are then forged via the compressive forces of being drawn through a die to form a single-wire conductor.

Ken-san says about the forging process, “The PC-Triple C/EX conductor was developed by FCM and Promotion Works, and is a breakthrough in which the current flows in both the silver and copper crystal structures while firmly integrating 5N grade silver and 5N grade copper by a forging manufacturing method into a single conductor. Its conduction rate is 105% IACS of copper alone, and it is no exaggeration to say that it has already reached superconductivity. At Acoustic Revive, this PC-Triple C/EX is adopted as a single wire with the maximum manufacturing diameter, which makes it possible to reproduce ultra-wide range with unprecedented transmission speed.”

A quick note from me about “superconductivity” to those who have might not have experience with the topic: Being involved with projects using superconducting wires and materials at the US national scientific laboratory I worked at as a physical scientist before I retired, I can tell you that Ken-san is not saying that the PC-Triple C/EX conductor is a “superconductor” in the scientific sense of the word (i.e. in a superconductor the resistance drops to zero when the material is cooled below its critical temperature), as at this point in time a room-temperature superconducting material does not exist. Rather, Ken-san is saying that the PC-Triple C/EX forged silver-copper hybrid conductor is a “super” conductor in terms that it exceeds the IACS rating of pure copper, which is defined as 100%, and matches the IACS rating of pure silver at 105%. I mention this to clarify as I didn’t want what Ken-san is saying to be misunderstood as a scientific claim of room temperature superconductivity.

Acoustic Revive commissioned custom high-performance RCA plugs manufactured by the Matsukin Company for use in the RCA Absolute FM Interconnect. They feature a vibration damping structure composed of duralumin (a hard, light alloy of aluminum with copper and other elements) and brass, and carbon fiber. The metal structure has a non-magnetic silver-rhodium plating. The plug’s electrode is made of a tellurium copper alloy, which offers a conductivity of 57% instead of the more typical 38% of a brass electrode. These RCA plugs also incorporates screw fasteners for the conductors instead of soldered joints, so there no conduction deterioration due to solder (below).

Ken-san says, “Finally, we jointly developed a new screw fastening method with Matsukin Co., Ltd., which eliminates the sound quality degradation of solder.”

The “FM” in the product name of the Acoustic Revive RCA Absolute FM Interconnects comes from the use of FINEMET® beads in their design. FINEMET® beads are composed of a nanocrystalline soft magnetic material for noise suppression, and you can see in the graphic below the level of noise suppression they offer.

In the graphic below you can see a cross section of the construction of the Acoustic Revive RCA Absolute FM Interconnects.

Working from inside to outside of the diagram above, you can see the PC-Triple C/EX forged silver-copper hybrid solid-core wires coated with a fluorine based insulating material. The conductors reside within natural silk tubing which provides an air dielectric layer and damping for the conductors. The next layer is flexible copper tubing coated in Teflon that provides shielding. The outer layer is high-carbon mesh tubing that provides additional shielding and an antistatic effect.

I’ll be putting them in my vintage Altec A5 Voice of the Theatre loudspeaker-based audio-visual system in the near future for some run-in time.

The New Acoustic Revive Absolute PC-Triple C/EX Lead Wires

If you’ve never had a chance to try high-performance headshell leads yet, you’re in for a treat one of these days, as they can make a remarkable difference, and as much a difference as high-performance power cords, speaker cables, or interconnects can!

The new Acoustic Revive Absolute PC-Triple C/EX Lead Wires leads use the same PC-TripleC /EX forged hybrid silver-copper conductors, but in a Teflon insulation in a 1mm gauge appropriate to headshell leads. The cartridge clips are made by the Matsukin Company in Tomioka City.

About the lead wires, Ken-san says, “The Absolute PC-Triple C/EX lead wires are manufactured by Mr. Shingo Tadasawa of KS-REMASTA who is a lead wire artisan.”

Suffice it to say that Mr. Shingo Tadasawa has turned building headshell lead wires using exotic wire – like the PC-Triple C/EX – into an art form, and he has created quite a sensation in Japan with audio enthusiasts and music lovers for his lead wires’ high-performance musical & sonic attributes. I wish that my photo did them justice – they are beautifully made.

Having built quite a number of tinned-copper lead wires myself, I can attest how difficult it can be to get the sort of beautiful result that Mr. Shingo Tadasawa of KS-REMASTA has achieved with his lead wires.

If you search on “Mr. Shingo Tadasawa of KS-REMASTA” you’ll find mini-reviews on various Japanese web sites of his lead wires – they are works of musical art!

I’ve got four other components in my review queue ahead of these new Acoustic Revive Absolute cable products, so it will be some months before their full review appears at Positive Feedback.

However, as is my custom, I will blogging my impressions of them as I proceed towards their full review, and it’s likely you’ll see them making appearances in the upcoming reviews of the First Watt SIT-3 stereo amplifier, the Soundsmith Zephyr Mk III phonograph cartridge, and the Still Audio EL84 integrated amplifier, for example.

For more information about Acoustic Revive products in the USA please contact Mr. Joe Cohen at The Lotus GroupThe USA pricing information for the Acoustic Revive cables are as follows:

  • The Absolute Power Cords in 2-meter length are $11,950 USD, with additional length by quote.
  • The RCA Absolute FM Interconnects are $11,950 USD for a 1-meter pair, and each additional 1/2 meter adds $5250 USD.
  • The PC-TripleC/EX Headshell Leads are $1075 USD for a set.

Ok, that’s it for now, and as always thanks for stopping by, and may the tone be with you!

 Posted by at 3:58 pm
Jul 082018
 

I am hard at work writing up my listening impressions for the First Watt SIT-3 stereo power amplifier review for Positive Feedback, which I hope to have completed in the next few weeks or so.

Until the review is published, I thought you would enjoy a “sneak peek” into the upcoming review – enjoy!

¸¸.•*¨*•♫♪ The First Watt SIT-3 Stereo Power Amplifier by Nelson Pass ¸¸.•*¨*•♫♪

Pretty much everyone involved in enthusiast audio has heard of Nelson Pass, and for good reason, as Nelson has been a central figure in the audio design world since the mid-1970’s.

Nelson at home enjoying a glass of wine during a listening session with Positive Feedback Editor David W. Robinson. Photograph by David W. Robinson, copyright (c) 2018, all rights reserved.

I asked Nelson if he would tell me a little about his early years, about how he first got involved in music and audio in the period prior to his adventures as the audio designer we know him as today.

Nelson told me, “I was born in Massachusetts and the family moved to Los Angeles in 1957, and then to Santa Rosa in 1958, where I grew up until I went to University of California, Davis (UC Davis) in 1969. From a fairly early age my radio ran all night long. My neighbor friend and I built a lot of stuff and eventually these two activities merged into DIY audio. I was building speakers when I was 15, but I started playing inside amplifiers a couple years later.”

Nelson started studying physics at UC Davis in 1969, earning a Bachelor of Science in physics in 1974. During his time as a physics student at UC Davis Nelson founded his own company to design and manufacture loudspeakers, called PMA, and was also hired by ESS to do research and development related to loudspeaker crossover and enclosure design work. Nelson arrived at ESS just before Oskar Heil who developed the famous ESS AMT 1 “Air Motion Transformer” loudspeaker.

Nelson worked at ESS during 1972 and 1973, a period where he gained a lot of knowledge about audio circuit designs through studying the schematics for op-amps in the National Semiconductor application books, and by repairing all brands of amplifiers for Sun Stereo as a service manager.

During that time in audio interest in solid-state amplifiers began to eclipse interest in vacuum tube amplifiers as audio enthusiasts began to desire more powerful amplifiers. A lot of the solid-state amplifiers of that period were using Class AB or Class B designs, but they didn’t sound too good compared to the Class A vacuum tube amplifiers, so interest rose in developing high-powered Class A solid-state designs that had better sound quality.

Nelson told me that his first unique amplifier design was in 1973, a Class A solid-state design. Nelson continued to incorporate what he was learning about sound quality and solid-state circuits into his own amplifier designs, and in 1974 Nelson and a colleague from ESS, René Besne, left ESS and founded Threshold Audio in December of 1974, the same year that Nelson graduated from UC Davis with a physics degree.

Threshold 800A power amplifier.

Nelson designed the amplifier circuit and selected the circuit components, and René did the industrial design to develop the amplifier’s appearance and ready it for production. Their work resulted in the Threshold 800A amplifier, which was a Class A amplifier that had 200 watts per channel output into 8 Ohms, with an innovative dynamic bias approach that helped reduce power consumption and heat while maintaining Class A sound quality. The Threshold 800A amplifier would go on to be a favorite of audio engineer and founder of Stereophile, J. Gordon Holt, as well as audio enthusiasts around the world.

Pass Labs

Nelson left Threshold Audio in 1991 to found Pass Labs so he could enjoy broader investigation into his own audio design interests. Today through Pass Labs Nelson offers a full range of audio electronics including amplifiers, preamplifiers, integrated amplifiers, and even a headphone amplifier.

Pass Labs’ current power amplifiers cover a broad range of audio enthusiast interests from the massively powerful and beautifully constructed X600.8 monaural amplifiers capable of delivering 600 watts of superb performance into 8 ohms for the most challenging loudspeaker loads (above), all the way down the power scale to the svelte XS25 stereo amplifier that delivers 25 watts per channel into 8 Ohms, that has been receiving accolades from reviewers for its lower-powered musical finesse on easier to drive loudspeakers (below).

The Pass Labs website describes Nelson’s approach to building amplifiers, “At Pass we build amplifiers with excessive output stages, huge heat sinks and massive power supplies. We use the highest quality components in simple linear topologies, assembled and tested with great care in Auburn, California. They measure well and sound great. They are heavy, reliable and expensive.”

Now allow me to take you back in time for a moment to the late 1980s and early 1990s to a parallel audio universe, where American audio enthusiasts began to become interested again in very simple and relatively affordable low-powered single ended triode (SET) vacuum tube amplifier designs for their exceptionally musical sound quality. Individuals like Don Garber (300B SET photo below), Herb Reichert, JC Morrison, Gordon Rankin, and others began building amplifier designs that were embraced by the “audio everyman” searching for a “sound of live music” reality.

There was really no one during the late 1980s and early 1990s building affordable and simple single-ended analogs of SET amplifiers with solid-state devices like metal-oxide-semiconductor field-effect transistors (MOSFET), junction gate field-effect transistors (JFET), or static induction transistors (SIT), until in 1997 when Nelson released the Pass Labs Aleph 3 (below).

The Aleph 3 was relatively low powered at 30 watts per channel, and was described by Nelson as, “… the first of the newest generation of amplifiers from Pass Labs. This design results from my commitment to create the best sounding product, a simple circuit having the most natural characteristic. The Aleph 3 integrates power MOSFET devices and pure single-ended Class A operation in a simple two-gain-stage topology with the sole purpose of recreating subjectively natural sound.”

Pass Labs Aleph 3 circuit.

While I have very much enjoyed the musical delights of low-powered single-ended triode or pentode amplifiers (SET and SEP, respectively), intrigued by the Pass Labs Aleph 3, I bought one in 1997 to see how it compared to the vacuum tube amplifiers I was familiar with.

MOSFET power curves

The Aleph 3 used MOSFETs in its simple single-ended Class A circuit, and it turns out that MOSFETs (and JFETs) have power curves (above) that look quite similar to the power curves for pentode vacuum tubes (below).

Pentode power curves.

Over the years I have really enjoyed the pentode circuits I have listened to, like that of the 5-watt per channel Almarro A205A integrated amplifier, for example, that uses EL84 vacuum tubes in a single-ended pentode circuit, and which I still enjoy listening to today powering my vintage Altec 832A loudspeakers.

I thought the Aleph 3 compared favorably with the SET (and SEP) designs I was familiar with, but it had the added benefit of 30 watts per channel output, which opened up a broader range of loudspeaker compatibility than most SET vacuum tube amplifiers could accommodate.

I loved the Aleph 3’s no-nonsense appearance with its huge heat sinks encircling the chassis, its ultra-reliability, and its low cost of maintenance (no expensive vacuum tubes to replace), not to mention that its power output of 30 watts per channel sounded great on my Spendor SP-1/2 loudspeakers in the apartment I lived in at the time.

I thought the Aleph 3’s price of $2400 USD was fair as well, and it was something that I could actually afford to buy as an audio enthusiast back in 1997. In 2018 dollars the Pass Labs Aleph 3 would go for $3751 USD, which is comparable to the First Watt SIT-3’s price of $4000 USD that is the subject of this review.

The Aleph 3’s simple design, excellent sound quality, greater loudspeaker flexibility, high reliability, low cost of operation, and affordable price made the Aleph 3 a hit with audio enthusiasts, and for the first time there was a single-ended solid-state design that was a viable alternative to low-powered SET or SEP amplifiers.

Pass DIY 

Nelson had become intrigued by the performance possibilities of low-powered amplifiers and wanted to continue his exploration into interesting low-powered amplifier designs (and other stuff), which didn’t really fit into the Pass Labs product lines.

Towards that end in 1998 Nelson founded Pass DIY and First Watt to explore novel amplifier designs in an environment unfettered by commercial concerns.

Nelson’s long involvement in and appreciation for do-it-yourself (DIY) audio is described on the Pass DIY website.

“Nelson Pass has been an early contributor to the audio DIY scene; It has been said that Nelson has a knack of explaining engineering things very clearly in a few words, and that he obviously enjoys doing it. He is also a very active contributor at www.diyaudio.com. Being very generous with advice, tips, and complete amplifier designs that people can build.”

Nelson says, “I like to speak to the teenager (me) who wanted to know this stuff – that’s my audience. There are always people who appreciate a decent explanation that gets to the meat and potatoes. I see it all as light entertainment with a little education thrown in. The academic paper approach has its place, but it seems intended for people who mostly understand the stuff already. If you want to communicate with DIYers, you depend more on colorful analogies, a little hand waving, and very little differential calculus. I get lots of personal satisfaction out of the whole enterprise. It gives me an outlet for some cool ideas and things that otherwise would stay bottled up, and I have an excuse to explore offbeat approaches purely for their entertainment value. Also, the process of communicating DIY stuff is a two-way street – I would say I get about as much as I give.”

Nelson enjoys giving away designs to the DIY audio community, as well, and he loves the creativity of the DIY community.

Nelson also regularly participates in and supports the yearly Burning Amp Festival which draws DIY audio enthusiasts from around the world.

Nelson likes simple amplifier circuits because they tend to sound better, and also because by studying the possible variations in simple circuits and their component parts you can get a better understanding of how an amplifier can deliver a particular signature sound.

Most vacuum tube audio circuit designs have been well developed and documented over time, and they are well understood, but in the realm of solid-state there are a high-amount of amplification devices and circuits that remain to be investigated.

A solid-state device that Nelson thought deserved further investigation in simple Class A circuits was the vertical field-effect transistor (VFET).

Sony VFET

Nelson said, “Examples of VFETs were produced by Sony and Yamaha forty years ago and appeared in power amplifiers produced from about 1975 through 1980. These amplifiers are now prized for their exceptional sound, the credit popularly going to the linearity of the VFETs. They were called VFETs at the time because they have a vertical (not lateral) structure. The subsequent invention and dominance of vertical MOSFETs (metal oxide semiconductor field effect transistor) made use of the term confusing, so now they are generally referred to as static induction transistors (SIT), except perhaps as reference to these original parts.”

Power curves for a Sony 2SK82 VFET.

The Sony VFET had power curves (above) that looked a lot like the power curves for triode vacuum tubes, like the 300B (below), and they were notable for their rich, dimensional, and natural “triode-like” sound quality.

300B power curves

Nelson says about the Sony VFETs, “I began working with these transistors as well, and the first result was an amplifier presented at the 2013 Burning Amp Festival in San Francisco. It was a push-pull Class A circuit consisting of only three parts, one each of the 2SK82 and 2SJ28 and a small Jensen coupling transformer. (This did not count the power supplies). It delivered 20 watts at reasonably good gain and low distortion and did so without feedback. I am told that it sounded very good …”

Nelson would go on to offer DIY enthusiasts amplifier kits using the Sony VFETs through www.diyaudio.com.

First Watt

First Watt is Nelson’s audio equivalent of the Lockheed Martin Skunk Works that develops advanced and/or secret aircraft projects in an environment that is unhindered by the usual commercial or bureaucratic concerns, like the famous U-2 or SR-71 Blackbird spy planes, for example.

In that same “skunk works” spirit of exploring the cutting edge of innovation, Nelson says, “First Watt exists because I wanted to explore a variety of amplifier designs in what I think of as neglected areas – amplifiers that might not fit into the mainstream and are probably not appropriate to my more commercial enterprise, Pass Labs. With oddball characteristics and output power ratings of 25 watts or less, First Watt is not for most people. If you have efficient loudspeakers, listen at reasonable levels and are obsessed about subjective performance, then you probably have come to the right place. If you want reliable audio product, then you really have come to the right place. For twelve years First Watt has had a near-zero failure rate.”

Nelson has now developed seventeen First Watt amplifiers at the cutting-edge of sound quality and musicality, and they all have 25 watts or less output into 8 Ohms.

All of the First Watt amplifiers feature minimalist circuits with little or no feedback and are highly innovative design approaches to Class A circuits, using either metal-oxide-semiconductor field-effect transistors (MOSFET), junction gate field-effect transistors (JFET), or static induction transistors (SIT), and with some of the designs being current sources instead of the more usual voltage sources, often being single-ended, and sometimes having no voltage gain at all!

Aficionados of low-powered tube amplifiers ooh and ahh over the musical and sonic performance of the 300B, 2A3, 45, and PX25 triode vacuum tubes developed in 1938, 1932, 1929, and 1935, respectively, and the 1920’s and 1930’s were certainly good years for developing great sounding low-powered triode vacuum tubes.

Some audio enthusiasts may not realize it, but MOSFETs were developed in 1959 by Dawon Kahng and Martin M. (John) Atalla at Bell Labs; JFETs were first patented by theoretical and applied physicist Heinrich Welker in 1945 (Westinghouse and Bell Labs); and SITs were developed by Japanese engineers Jun-ichi Nishizawa and Y. Watanabe in 1950, all within the period that is oft’ cited as the Golden Age of Audio.

Until Nelson started his investigations into low-powered MOSFETs, JFETs, and SITs used in simple Class A circuits, no one had really applied the same sort of careful attention to solid-state devices as had been done by audio experimenters working with the 300B, 2A3, 45, and PX25 triode vacuum tubes that you might have read about in the Japanese audio experimenters periodical MJ Audio Technology, whose first issue was published in 1924.

Nelson’ First Watt amplifier designs have often been compared to these low-powered vacuum tube single-ended-triode (SET) amplifier designs for their sheer musicality and sonic prowess, though Nelson is quick to point out that his designs “… are not designed to mimic tubes as such. These amplifiers share some of the characteristics of the better tube products in that they have simple circuits with minimal or no feedback and emphasize performance of individual gain devices. In some ways they are better than tubes, in other ways perhaps not.”

The proof is in the listening though, and if you’ve had an opportunity to listen to Nelson’s First Watt amplifiers you know they are extremely good in terms of musicality and sonics, and they are certainly competitive with the single-ended-triode (SET) vacuum tube amplifiers I have owned.

Nelson’s First Watt amplifiers also have the added benefit of reasonable prices and extreme reliability, and with no expensive vacuum tubes to periodically replace, they also have very low life-cycle costs for the audio enthusiast.

Nelson’s interest in exploring SIT-based amplifiers at First Watt continued to grow, and then one day Jeff Cassidy at SemiSouth contacted Nelson about the possibility of doing a custom run of silicon carbide SITs.

Nelson said about the event, “Sometimes, though, things just fall into your lap. A couple years ago I was talking to Jeff Cassidy at SemiSouth and he mentioned that at one time they had made a special run of static induction transistor devices on some kind of military/industrial contract, and that one of their technical people had remarked that they were nearly ideal for use in audio amplifiers. “Really”, says I, “Do you have any of them left over?” No, the customer scooped them all up, but they would be interested in making more. The price of a small run was astronomical (to me, at least) and I spent quite a bit of time pondering the risk. And then I wrote the check and didn’t look back. After a few months I had a small batch of SITs with my name on them, and I started playing. It took about a year and a half to arrive at the designs of the SIT-1 and SIT-2 amplifiers, and it has been a revelatory experience.”

The eventual result of those “skunk works” SITs from SemiSouth was that in 2012 Nelson introduced the SIT-1 monaural amplifiers and the SIT-2 stereo amplifier based on his new custom SemiSouth SITs.

Nelson says about them, “Both were rated at 10 watts per channel and used the SIT as the only gain device, operated without feedback in Common Source Mode, which delivers both voltage and current gain. The two amplifiers were the most successful in the history of First Watt and were made into 2017 (emphasis mine – Jeff).”

For just a moment let’s think about Nelson’s statement that the SIT-1 and SIT-2 were the most successful amplifiers in the history of First Watt. If you’re like me you are wondering what made Nelson’s SIT-1 and SIT-2 amplifiers so successful with listeners. I think it would be too simplistic to just say that listeners liked the way they sounded, even though that’s true, the question becomes “What exactly was it that listeners liked about the way the SIT-1 and SIT-2 amplifiers sounded?”

300B power curves

Well, it turns out that the Nelson’s custom run of SemiSouth silicon carbide SITs sounded really good, with their performance being modeled after the power curves of triode vacuum tubes, so the answer to the single ended SIT-1 and SIT-2’s popularity was that they sounded very much like the best single ended triode (SET) vacuum tube amps. Let that sink in for a moment.

Power curves for a Sony 2SK82 VFET.

Nelson said about the SIT-1 and SIT-2, “The SIT devices allow operation with only one gain stage. In fact, the SIT-1 has only one transistor in the entire amplifier, without feedback and even without degeneration. It’s as simple and raw an amplifying circuit as you could imagine. I have built such simple amplifiers before using MOSFETs and power JFETs, but I was not at all prepared for the quality of sound that I got with the SITs. It was like magic. The SIT-1 and SIT-2 are special amplifiers. They have single gain stages – the input signal goes into the gate of the SIT and comes out the drain amplified and driving the loudspeaker. There is no feedback or degeneration. They run single-ended Class A …”

SIT-1 circuit

Nelson says there are three primary advantages of triode vacuum tubes and SIT power transistors for audio use. The first is that they allow you to build an amplifier with a single gain stage that provides both current and voltage gain, while having high input impedance and low output impedance, so no feedback is necessary. Secondly, you can choose a voltage-current load-line that provides very low distortion. Thirdly, their soft overload characteristics mean that when they’re driven hard to clipping they distort gracefully by producing compressed and rounded waveforms instead of unpleasant sounding sharp clipping.

Nelson goes on to say, “Unfortunately triode performance is limited partly by the need to transform the high voltage / low current operation of the triode down to the low voltage / high current domain of loudspeakers. This means a transformer and all the distortion comes with it. Of course, it would be nice if triodes drove speakers without transformers.”

The SITs don’t have the transformer issue SET amplifiers, so there is very little distortion, and you could think of the SIT-1 and SIT-2 a little bit like an output transformer less (OTL) 300B single ended triode (SET) amplifier.

The First Watt SIT-3 Stereo Amplifier

Now to add to the intrigue of the popularity of the SIT-1 and SIT-2, Nelson has for 2018 released his third version of an amplifier based on his custom run of SemiSouth “skunk works” static induction transistors, the very innovative and creatively designed First Watt SIT-3.

First Watt SIT-3 power amplifier.

The new SIT-3 is a Class A stereo amplifier using Nelson’s SemiSouth SIT power transistor and puts 10 watts into 16 Ohms (as with my vintage Altec loudspeaker collection), 18 watts into 8 Ohms (as with my Tannoy Westminster Royal SE loudspeakers), and 30 watts into 4 Ohms.

The SIT-3 differs from the SIT-1 and SIT-2 in that it operates in Common Drain Mode rather than their Common Source Mode.

Nelson explains their differing operational modes by saying, “The channels of the SIT-1 and SIT-2 consisted of a single SIT operated in Common Source Mode in which (conceptually) the signal comes into the gate and appears amplified at the drain pin, but phase inverted. The source pin is grounded. The amplification with Common Source operation is both voltage and current, and the phase inversion is corrected by reversing the output terminals. The SIT-3 goes in another direction, using Common Drain operation, where the signal goes into the gate pin and comes out the source pin and the drain of the FET is grounded (literally attached to ground). This mode only provides current gain – voltage gain is provided by a high-quality voltage step-up transformer which takes the input signal from a preamplifier (or other device) and boosts the voltage. There is no phase inversion at the loudspeaker terminals.”

Nelson goes on to say, “In both approaches, the SIT does a good job of amplifying the signal without feedback, but Common Drain operation delivers the amplification with much lower distortion and noise and also a much better damping factor for the loudspeaker. The trade-off is the addition of the input transformer, but I think you will find the compromise there is small with respect to the sound quality. Common Drain has the same simple spectral distortion character that graced the SIT-1 and SIT-2 and allows similar control of the amplitude and phase of the second harmonic content, but at a much lower distortion figure.”

If you look closely at the power output of the SIT-1, SIT-2, and SIT-3, you’ll notice that the SIT-3 outputs 18 watts into 8 Ohms, almost double the 10 watts into 8 Ohms of the SIT-1 and SIT-2.

I asked Nelson how the SIT-3 achieves an output of 18 watts compared to the SIT-1 and SIT-2’s 10 watts, given that they all share the same SemiSouth SIT device.

Nelson said, “It (the SIT-3) is unique because it operates in a push-pull topology I call DEF – the depletion type N channel SIT is mated with an enhancement type P channel MOSFET to form a self-biasing Class A power follower. Apart from elegant simplicity, this has the square-law character of a triode circuit but with more current available to the load. Compared to the single-ended SIT-1 and 2, this push-pull Class A has twice the power into 8 ohms, eight times the power into 4 ohms, 10 times the damping factor, and one-fifth the distortion while having that second harmonic character. This follower stage does not provide voltage gain, so the SIT-3 uses a high-quality auto-former to boost the preamp voltage by 11 dB, buffered by push-pull JFET followers to give an input impedance of 200K Ohms.”

Simply speaking, the output stage of the SIT-3 is a push-pull depletion/enhancement mode follower (DEF) which delivers about twice the output current of the single-ended SIT-1 and SIT-2 amplifiers.

Here’s a circuit schematic of the First Watt SIT-3 stereo amplifier:

SIT-3 Circuit

About it Nelson says, “You can see the input JFET followers driving the auto-former, which develops voltage gain for the power output followers. Besides the unusual DEF / SIT output stage, you might notice the inverted power supply, which dramatically reduces supply noise seen by the SIT. This design requires careful selection of the characteristics of each SIT matched to the MOSFET – their gate voltages must be carefully matched, and fortunately this SIT device falls into the range where such matching is possible. The actual circuit is hardly more complicated and includes a few new tricks to get both the purest square-law performance with solid stability.”

Nelson’s home listening room during a recent visit by Positive Feedback Editor David W. Robinson. Photograph by David W. Robinson, copyright (c) 2018, all rights reserved.

I should mention that Nelson is very proud of the First Watt SIT-3 and how it turned out, and he says, “This is one of those all-night, year-after-year pieces.” Note the First Watt SIT-3 in Nelson’s home listening room in the photo above.

¸¸.•*¨*•♫♪ ¸¸.•*¨*•♫♪ ¸¸.•*¨*•♫♪

Ok, that’s it for now! That should suitably whet your appetite for the review of the First Watt SIT-3  at Positive Feedback in the coming weeks.

I’ve been enjoying listening to the First Watt SIT-3 in my Westminster Royal SE loudspeaker based system.

Next the First Watt SIT-3 will be migrating to my vintage Altec loudspeaker-based systems for a little more musical fun and games!

As always, thanks for stopping by, and may the tone be with you!

 Posted by at 1:05 pm
Jun 282018
 

A couple of memorable Pass Labs moments in my life came to mind as I have been listening to Nelson Pass’ new First Watt SIT-3 stereo power amplifier over the last two weeks, a design which Nelson is very pleased with, I am told (and which I will be interviewing him about for the Positive Feedback review of the SIT-3).

Pass Labs Aleph 3 Stereo Power Amplifier

My first memorable Pass Labs moment was way back in 1997 – twenty-one years ago now – when I owned a Pass Labs Aleph 3 stereo power amplifier (below), and it was my introduction to using a solid-state amplifier versus a tube amplifier in my stereo system.

I loved the Aleph 3’s no-nonsense appearance with its huge heat sinks encircling the chassis, its ultra-reliability, and its low cost of maintenance (no expensive vacuum tubes to replace), not to mention that its modest power output of 30 watts per channel sounded great on the Spendor SP-1/2 loudspeakers I had at the time.

Pass Labs Aleph 3 simplified circuit.

Nelson said about his Aleph 3, “The Aleph 3 integrates power MOSFET devices and pure single ended Class A operation in a simple two-gain-stage topology with the sole purpose of recreating subjectively natural sound.”

I thought the Aleph 3’s price of $2400 USD was fair as well, and it was something that I could actually afford to buy as an audio enthusiast back in 1997. In 2018 dollars the Pass Labs Aleph 3 would go for $3751 USD, which is comparable to the First Watt SIT-3’s price of $4000 USD.

MOSFET power curves look a lot like pentode vacuum tube curves. Diagram from Nelson Pass.

MOSFETs have power curves that look a lot like pentode vacuum tubes, and I’ve enjoyed the various pentode based vacuum tube amplifiers I’ve had quite a lot for their unique and engaging presentation of music, just as I did the Aleph 3.

300B vacuum tube power curves. Diagram from Nelson Pass.

I would eventually be lured away from my Aleph 3 by the siren song of triode vacuum tubes such as the 2A3, 45, 300B, and the 845.

In the diagram above you can see the power curves for a 300B vacuum tube, and notice how it differs from the MOSFET’s pentode-like power curves.

Pass Labs Sony VFET 40 Year Commemorative Amplifiers

Chad Kassem’s Acoustic Sounds teamed with Sony for loudspeakers & Nelson Pass for amplification, and it was my favorite of the show, with smooth, natural, analog sound, and with Chad doing DJ duties.

My second memorable Pass Labs moment was in 2015 when I visited the Rocky Mountain Audio Fest, where I heard the best combination of musicality and sound that I’ve ever heard at an audio show while listening to music with Chad Kassem in his Acoustic Sounds room using the Pass Labs Sony VFET 40 Year Commemorative amplifiers driving Sony loudspeakers, using Chad’s vinyl as a source. I could have easily lived with Chad’s system and never looked back, it was amazing!

The Pass Labs Sony VFET 40 Year Commemorative amplifiers used Sony VFETs, which are now more commonly referred to as “SITs” to avoid confusing them with vertical MOSFETs.

As Nelson said about the Pass Labs Sony VFET 40 Year Commemorative amplifiers, “Examples of “VFETs” were produced by Sony and Yamaha forty years ago and appeared in power amplifiers produced from about 1975 through 1980. These amplifiers are now prized for their exceptional sound, the credit popularly going to the linearity of the VFETs. They were called VFETs at the time because they have a vertical (not lateral) structure. The subsequent invention and dominance of vertical MOSFETs (Metal Oxide Semiconductor Field Effect Transistor) made use of the term confusing, so now they are generally referred to as Static Induction Transistors (SIT), except perhaps as reference to these original parts.”

Sony VFET / SIT used in the Pass Labs Sony VFET 40 Year Commemorative amplifiers. Photo from Nelson Pass.

I suppose the Pass Labs Sony VFET 40 Year Commemorative amplifiers could also be referred to as the Pass Labs Sony “SIT” 40 Year Commemorative amplifiers using contemporary nomenclature, and they reside in the “family tree” of SIT amplifiers that Nelson has designed.

In the above photo you can see the Sony VFETs / SITs that Nelson used in the Sony VFET 40 Year Commemorative amplifiers .

Power curves for a Sony 2SK82 VFET. Diagram from Nelson Pass.

Why did I like the Pass Labs Sony VFET 40 Year Commemorative amplifiers sound so much?

Part of the reason was no doubt due to the VFETs / SITs power curves looking a lot like the power curves for triode vacuum tubes like the 300B, noted for their rich, dimensional, and natural sound quality.

Check out the similarity of the 300B power curves to the Sony 2SK82 VFETs / SITs in the power curve diagrams shown above.

The Pass Labs Sony VFET 40 Year Commemorative amplifiers didn’t sound exactly like good DH-SET 300B amplifiers, they sounded much better to my ears!

Pass Labs and First Watt

The First Watt SIT-3 stereo amplifier designed by Nelson Pass.

I’ve gotten a number of questions from readers about the relationship of Pass Labs to First Watt, so before I talk more about the First Watt SIT-3 amplifier that I’ve been listening to for the last couple of weeks, let me explain the reason for the existence of the two Nelson Pass enterprises of Pass Labs and First Watt.

First Watt is Nelson Pass’ audio equivalent of the Lockheed Martin’s “Skunk Works” that develops advanced and/or secret aircraft projects in an environment that is unhindered by the usual commercial or bureaucratic concerns, like the famous U-2 or SR-71 Blackbird spy planes, for example.

In that same “skunk works” spirit of exploring the cutting edge of innovation, Nelson says, “First Watt exists because I wanted to explore a variety of amplifier designs in what I think of as neglected areas – amplifiers that might not fit into the mainstream and are probably not appropriate to my more commercial enterprise, Pass Labs. With oddball characteristics and output power ratings of 25 watts or less, First Watt is not for most people. If you have efficient loudspeakers, listen at reasonable levels and are obsessed about subjective performance, then you probably have come to the right place. If you want reliable audio product, then you really have come to the right place. For twelve years First Watt has had a near-zero failure rate.”

Nelson has now developed seventeen First Watt amplifiers at the cutting-edge of sound quality and musicality, and they all have 25 watts or less output into 8 Ohms.

All of the First Watt amplifiers feature minimalist circuits with little or no feedback and are highly innovative design approaches to Class A circuits, using either metal-oxide-semiconductor field-effect transistors (MOSFET), junction gate field-effect transistors (JFET), or static induction transistors (SIT), and with some of the designs being current sources instead of the more usual voltage sources, often being single-ended, and sometimes having no voltage gain at all!

Aficionados of low powered tube amplifiers ooh and ahh over the musical and sonic performance of the 300B, 2A3, 45, and PX25 vacuum tube designs developed in 1938, 1932, 1929, and 1935, respectively. The 1920’s and 1930’s were good years for developing low-powered triode vacuum tube designs.

Some audio enthusiasts may not realize that MOSFETs were developed in 1959 by Dawon Kahng and Martin M. (John) Atalla at Bell Labs; JFETs were first patented by theoretical and applied physicist Heinrich Welker in 1945 (Westinghouse and Bell Labs); and SITs were developed by Japanese engineers Jun-ichi Nishizawa and Y. Watanabe in 1950, which was also during the period that is often cited as the Golden Age of Audio.

MJ Audio Technology magazine from Japan.

However, until Nelson Pass and his innovative Pass Labs and First Watt designs, the same careful attention had not been applied to implementing MOSFETs, JFETs, and SITs for maximum musical and sonic performance into simple Class A circuits, as had been done by audio experimenters working with the 300B, 2A3, 45, and PX25 vacuum tubes that you might have read about in the Japanese audio experimenters periodical MJ Audio Technology (above), whose first issue was published in 1924.

Nelson Pass’ First Watt amplifier designs have often been compared to these low-powered vacuum tube single-ended-triode (SET) amplifier designs for their sheer musicality and sonic prowess, though Nelson is quick to point out that his designs “… are not designed to mimic tubes as such. These amplifiers share some of the characteristics of the better tube products in that they have simple circuits with minimal or no feedback and emphasize performance of individual gain devices. In some ways they are better than tubes, in other ways perhaps not.”

The proof is in the listening though, and if you’ve had an opportunity to listen to Nelson’s First Watt amplifiers you know they are extremely good in terms of musicality and sonics, easily competitive with the single-ended-triode (SET) vacuum tube amplifiers I have owned, with the added benefit of reasonable prices, extreme reliability, and with no expensive vacuum tubes to periodically replace the First Watt amplifiers also have very low life-cycle costs for the audio enthusiast.

The First Watt SIT-3 Stereo Amplifier

I’ve been listening to the First Watt SIT-3 installed into the Westminster based system for a couple weeks now.

Now let’s talk a little bit about the First Watt SIT-3 from Nelson Pass that I’ve been listening to for the last few weeks.

In 2010 Nelson had SemiSouth make a small custom run of static induction transistors (SIT) made of silicon carbide that would deliver 10 watts into 8 Ohms, for use in upcoming First Watt amplifier designs.

Nelson’s custom SemiSouth Static Induction Transistor.

In 2012 Nelson introduced the SIT-1 monaural amplifiers and the SIT-2 stereo amplifier. Nelson says about them, “Both were rated at 10 watts per channel and used the SIT as the only gain device, operated without feedback in Common Source Mode, which delivers both voltage and current gain. The two amplifiers were the most successful in the history of First Watt and were made into 2017 (emphasis mine – Jeff).”

For just a moment let’s think about Nelson’s statement that the SIT-1 and SIT-2 were the most successful amplifiers in the history of First Watt. If you’re like me you are wondering what made Nelson’s SIT-1 and SIT-2 amplifiers so successful with listeners. I think it would be too simplistic to just say that listeners liked the way they sounded, even though that’s true, the question becomes “What exactly was it that listeners liked about the way the SIT-1 and SIT-2 amplifiers sounded?’

Well, it turns out that when the static induction power transistor was developed its performance was modeled after the power curves of a triode vacuum tube, and as Nelson says, “SIT devices have a unique characteristic which is of particular value for audio amplifiers. Quoting inventor Nishizawa’s patent abstract, “(The) drain-current to drain-voltage characteristic simulates the anode-current to anode-voltage characteristic of the triode vacuum tube very closely.””

It turns out that JFET’s and MOSFET’s have power curves that look a lot like a pentode vacuum tube, but the power curves for the SIT looks like a triode vacuum tube, so the answer to the single ended SIT-1 and SIT-2’s popularity was that they sounded very much like the best single ended triode (SET) vacuum tube amps. Let that sink in for a moment.

Nelson says there are three primary advantages of triode vacuum tubes and SIT power transistors for audio use. The first is that they allow you to build an amplifier with a single gain stage that provides both current and voltage gain, while having high input impedance and low output impedance, so no feedback is necessary. Secondly, you can choose a voltage-current load-line that provides very low distortion. Thirdly, their soft overload characteristics mean that when they’re driven hard to clipping they distort gracefully by producing compressed and rounded waveforms instead of unpleasant sounding sharp clipping.

Now to add to the intrigue of the popularity of the SIT-1 and SIT-2, Nelson has for 2018 released his third and final version of an amplifier based on his custom run of SemiSouth static induction transistors, the First Watt SIT-3.

The First Watt SIT-3 stereo amplifier designed by Nelson Pass.

The new SIT-3 is a Class A stereo amplifier using Nelson’s SemiSouth SIT power transistor and puts 10 watts into 16 Ohms (as with my vintage Altec loudspeaker collection) 18 watts into 8 Ohms (as with my Tannoy Westminster Royal SE loudspeakers), and 30 watts into 4 Ohms.

The SIT-3 differs from the SIT-1 and SIT-2 in that it operates in Common Drain Mode rather than their Common Source Mode.

Nelson explains their differing operational modes by saying, “The channels of the SIT-1 and SIT-2 consisted of a single SIT operated in Common Source Mode in which (conceptually) the signal comes into the gate and appears amplified at the drain pin, but phase inverted. The source pin is grounded. The amplification with Common Source operation is both voltage and current, and the phase inversion is corrected by reversing the output terminals. The SIT-3 goes in another direction, using Common Drain operation, where the signal goes into the gate pin and comes out the source pin and the drain of the FET is grounded (literally attached to ground). This mode only provides current gain – voltage gain is provided by a high-quality voltage step-up transformer which takes the input signal from a preamplifier (or other device) and boosts the voltage. There is no phase inversion at the loudspeaker terminals.”

Nelson goes on to say, “In both approaches, the SIT does a good job of amplifying the signal without feedback, but Common Drain operation delivers the amplification with much lower distortion and noise and also a much better damping factor for the loudspeaker. The trade-off is the addition of the input transformer, but I think you will find the compromise there is small with respect to the sound quality. Common Drain has the same simple spectral distortion character that graced the SIT-1 and SIT-2 and allows similar control of the amplitude and phase of the second harmonic content, but at a much lower distortion figure.”

If you look closely at the power output of the SIT-1, SIT-2, and SIT-3, you’ll notice that the SIT-3 outputs 18 watts into 8 Ohms, almost double the 10 watts into 8 Ohms of the SIT-1 and SIT-2.

I asked Nelson how the SIT-3 achieves an output of 18 watts compared to the SIT-1 and SIT-2’s 10 watts, given that they both share the same SemiSouth SIT power transistor.

Nelson said, “It (the SIT-3) is unique because it operates in a push-pull topology I call DEF – the depletion type N channel SIT is mated with an enhancement type P channel MOSFET to form a self-biasing Class A power follower. Apart from elegant simplicity, this has the square-law character of a triode circuit but with more current available to the load. Compared to the single-ended SIT-1 and 2, this push-pull Class A has twice the power into 8 ohms, eight times the power into 4 ohms, 10 times the damping factor, and one-fifth the distortion while having that second harmonic character. This follower stage does not provide voltage gain, so the SIT-3 uses a high-quality auto-former to boost the preamp voltage by 11 dB, buffered by push-pull JFET followers to give an input impedance of 200K Ohms.”

Simply speaking, the output stage of the SIT-3 is a push-pull depletion/enhancement mode follower (DEF) which delivers about twice the output current of the single-ended SIT-1 and SIT-2 amplifiers.

Here’s a circuit schematic of the First Watt SIT-3 stereo amplifier:

Simplified SIT 3 circuit schematic.

About it Nelson says, “You can see the input JFET followers driving the auto-former, which develops voltage gain for the power output followers. Besides the unusual DEF / SIT output stage, you might notice the inverted power supply, which dramatically reduces supply noise seen by the SIT. This design requires careful selection of the characteristics of each SIT matched to the MOSFET – their gate voltages must be carefully matched, and fortunately this SIT device falls into the range where such matching is possible. The actual circuit is hardly more complicated and includes a few new tricks to get both the purest square-law performance with solid stability.”

I should mention that Nelson is very proud of the First Watt SIT-3 and how it turned out, and he says, “This is one of those all-night, year-after-year pieces.”

First Watt SIT-3 in WRSE system.

After the First Watt SIT-3 from Nelson arrived, I replaced my usual vintage McIntosh MC30 monaural amplifiers with the First Watt SIT-3 stereo amplifier in my Tannoy Westminster Royal SE based system.

Classic Turntable Company hot-rodded Garrard 301, vintage McIntosh MX110Z tuner-preamplifier, and First Watt SIT-3 stereo power amplifier.

I’m probably about half-way through the normal 100 hour run-in on the First Watt SIT-3, and its performance seems to have largely stabilized now, and it is playing music very nicely.

I had abandoned the use of 45, 2A3, and 300B amplifiers after living with my Tannoy Westminster Royal SE loudspeakers for the last so many years, as none of them really had enough power to achieve natural sounding live-like levels on the Westminster’s, and even my 25 watts per channel vintage McIntosh MC225 fell just shy of being able to maintain live-like levels in the range of 92dB-98dB SPLs across a broad range of musical genres.

My 30 watts per channel vintage McIntosh MC30 monaural amplifiers power the Westminster’s quite easily, and seem to be at the sweet-spot for attaining live-like SPL’s, with more power than that just contributing a sense of ease to the Westminster’s overall presentation of music.

Tannoy Westminster Royal SE loudspeakers with the First Watt SIT-3 stereo power amplifier.

I wondered how well the First Watt SIT-3 at 18 watts per channel output would be able to drive my Westminster’s to live-like levels. The answer is that the SIT-3 does pretty well on most of the music I enjoy listening to, being able to do natural sounding SPL’s in the 80-90db range rather easily.

Once I got into the SPL range of 90-100dB (I even saw occasional peaks of 101dB SPL on some music), most of the time everything sounded fine, but it was clear that the nearer I got to the 100dB SPL level the SIT-3 began to sound stressed on my Westminster’s.

You can only expect so much volume-wise driving the Westminster’s with the First Watt SIT-3’s 18 watts, which by the way was similar to my results with the 25 watts per channel vintage McIntosh MC225 stereo amplifier on the Westminster’s.

If you are considering purchasing a First Watt SIT-3 of your own, you will want to make sure that in combination with your favored loudspeakers you are able to achieve the SPL levels you enjoy listening at, which will be a little different for everybody I suppose.

Vintage Altec 832A Corona loudspeakers.

My vintage Altec 832A Corona, vintage Altec A7 Voice of the Theatre, and vintage Altec A5 Voice of the Theatre loudspeakers are all much easier to drive than my Westminster’s, and I suspect the First Watt SIT-3’s 10 watts into 16 Ohms will be plenty of power to easily drive my vintage 16 Ohm Altec’s to live-like levels, about which I will be reporting on in-depth in my upcoming Positive Feedback review of the First Watt SIT-3.

Vintage Altec A5 Voice of the Theatre loudspeakers.

Leopold Stokowski’s Altec A7’s were a nice addition to my vintage Altec loudspeaker “stable”.

I have been having a blast listening to the First Watt SIT-3 in my Westminster loudspeakers based system, and I have been very impressed with the musicality and sonic prowess of the SIT-3 in my preliminary listening.

In the upcoming Positive Feedback review of the First Watt SIT-3 I will discuss its musicality & sonic performance in detail in several different system contexts, but for now suffice it to say that the SIT’s musicality performance on the basic elements of music were extremely good in terms of timbral realism (the unique ‘voices’ of instruments), the resolution of tone color (the ability to distinctly hear the chordal variations resulting from adding additional pitches to three tone triads), melody (the tune you ‘whistle while you work’), harmony (treble & bass accompaniments to the melody), rhythm (the steady beat that determines the tempo), tempo (speed), and dynamics (variations in loudness).

Likewise, I found the SIT-3’s sonic performance to be superb with respect to transparency (the ability to ‘see’ into the recording), resolution (the amount of detail in the audio signal that is audibly presented), soundstage (the ability to discern the three dimensions of the recorded space in width, height and depth), the soundspace (the ability to convey the acoustic sense of ‘space’ of the recording venue), and imaging (the ability to localize instruments & musicians on the soundstage).

Above all the way Nelson has voiced the First Watt SIT-3 beautifully integrates musicality & sonics in a way that I’ve found to maximize my emotional response to the music during my listening experiences, and there were times when I was absolutely in awe of the SIT-3’s way with the music.

I suspect that the First Watt SIT-3’s smooth, natural, vividly present sound quality will really appeal to a lot of listeners, and it certainly appeals to me.

How good is the First Watt SIT-3 stereo amplifier? Another reviewer mentioned to me that the First Watt SIT-3 is the best amplifier he has ever heard.

I can tell you that if you’re interested in a First Watt SIT-3 of your own you will want to act quickly, as there will not be many of them made, and once they are gone that will be it.

As always, thanks for stopping by, and may the tone be with you!

 Posted by at 9:39 am