Nov 112013

On Sunday afternoon Ron (center) and Leo (left) joined me for a fine day of hi-fi fun and games, and as usual we had a ball! (Sorry for the blurry photo. Note to self: remember to use the correct camera setting next time!)

Leo and Ron

After a lunch of a combo pizza and a few glasses of some mighty fine vino, we put together a set of binding post bypass style of speaker cable adapters for Leo’s vintage McIntosh MC30 mono amps so he could use modern speaker cable connectors on his amps.

Shrink wrapped adapter

For those of you not familiar with the vintage amplifiers, they use terminal blocks with screws to connect speaker cables, from back in the days when people only used a bare wire end to connect loudspeakers, and modern connectors are just too big too fit into their tight confines.

Below, that’s the terminal blocks on my vintage MC240 with a binding post bypass adapter in place, securing a pair of Panatela speaker cables, so you can see how they work. If you look close you can see how the spade connectors of the Panatela speaker cables are clamped to the bare end of Neotech wire, with the other end being held in place by the screw on the terminal block. These adapters work great!

completed binding post bypass adapter on MC240

Next time we’re going to build a set for George’s MC30 mono amps, and a pair for Leo’s vintage Marantz 8!

Mac MC30s

Marantz 8

We also had a great discussion about our favorite 6L6GC tubes. There’s a ton of great new stock 6L6GC tubes being made right now, so if your amps run 6L6GCs this is a good time to be alive! Arguably the prettiest of the bunch is the Tung-Sol 6L6G (which you can use in a circuit designed for 6L6GCs, unlike the NOS 6L6Gs which can’t handle it), and they’re one of the best sounding of the currently available 6L6 family tubes. That’s a quad of them with their sexy ST bottle shapes in my MC240 below.

Tung Sol 6L6G 2

On the vintage front the RCA 6L6GC black plates and the Philips 7581A are easy favorites, and I’d say it is about a draw between those musical titans. They sound different, but they are both great, and on some music I preferred the RCAs, and on other music the Philips 7581A.

That’s the RCA 6L6GC black plates below in my MC240. Expect to pay a small fortune for the RCAs if you are lucky enough to find them. You could probably buy 4 quads of the Tung Sol reissue 6L6Gs for what a quad of the RCAs would sell for. They’re good, but are they that good?

MC240 with RCA 6L6GC black plates

Here’s a photo (below) of the Philips 7581A in the MC240. The Philips are really great tubes and come in at less than half the price of RCAs. They are getting hard to find too.

MC240 with Philips

I had a digital front end set up for my upcoming review of the Mhdt Labs Stockholm V2 vacuum tube USB DAC that included an iMac with about 900 or so CDs loaded on it, and the Channel D Pure Music software that integrates nicely with iTunes (I’ll have more to say about Pure Music in another post – great software!).

In the review I’ll be comparing the Stockholm V2 to the Mhdt Labs vacuum tube Havana USB DAC, and to my vinyl front end, the final arbiter of how far digital has come!

Digital front end

Leo brought over his new McIntosh C2300 vacuum tube preamplifier (top) and we listened to it compared to my vintage McIntosh MX110Z (below).

Mac C2300

The C2300 is one beautiful looking preamplifier with its glass front, glowing green McIntosh logo, and blue meters!

system photo with c2300 and mx110z

Comparing the new C2300 to the vintage MX110Z was about what you would expect, with the C2300 being more transparent and resolving, and the MX110Z sounding more … well vintage … softer, warmer, and less transparent.

c2300 and mx110z with MC30s

The C2300 has more features than you can imagine, and a remote control for all of them!

I really like the fact that the C2300 – like the MX110Z – has tone controls. Tone controls are such a good idea for being able to fine tune a system to a room, a new component, or to different records, and the great designers of the Golden Age of Audio all knew that sort of adjustably was important (ergo the classic Marantz, McIntosh, et al, had tone controls). I hope tone controls come back into fashion, they’re awesome!

117 MX110Z

Ok, the MX110Z does win on one feature that it has that the C2300 doesn’t, that fantastic sounding vacuum tube tuner that pulls in my local National Public Radio station with ease! I have really been getting into listening to FM lately, and it sounds remarkably good.

With a few judicious tweaks to the tone controls we could make the C2300 sound quite a lot like the MX110Z. There is definitely a McIntosh ‘house’ sound that has crossed the five decades since the MX110Z was made. That’s impressive really, as the over 50 year older MX110Z and shiny new C2300 are both easily identifiable as McIntosh’s, and that’s a good thing! Kudos to McIntosh for honoring tradition!

A complete change of subject: I just heard from Frederik Carøe in Denmark – the founder of Duelund Coherent Audio – that he has started building a pair of 6.8 uF SILVER Duelund CAST paper-in-oil capacitors for me to try in the C1 position of the Duelund-WRSE external high-frequency crossovers! That is really exciting news!

view-of-the-Duelund-crossover 6.8uF cap on left

In the photo above you can see the Duelund 6.8 uF CAST copper capacitor (C1) in the left lower corner of the crossover. When the 6.8uF CAST silver capacitors arrive from Frederik all I’ll have to do is loosen the binding post clamps to slip out the leads, loosen the setscrew lugs to slip out the other leads, and then slide the new 6.8uF silver CAST capacitors in place and tighten everything back up – easy as that!

I’ll have a lot more to say as the story of the  Duelund 6.8 uF CAST silver capacitors develops in both blog posts along the way, as well as a full review at Positive Feedback Online in due time – stay tuned!

I hope you enjoyed Sunday afternoon with us at Jeff’s Place, and I hope you’ll come back again soon!

From our homes to yours, may the music warm your heart!

 Posted by at 10:16 am

  11 Responses to “Sunday Afternoon at Jeff’s Place”

  1. Jeff,
    If you like the 2300 get a new 2500 with build-in DAC and MC/MM. It’s a great pre-amp.
    Love your post, enjoy your music!

  2. Jeff

    The binding post bypass adapters for the MC30’s turned out awesome! Nice looking digital set-up you have put together to listen to those 1’s and 0’s


  3. Hi:

    Can anyone help me with a Crossover schematic for the Tannoy GRF Memory TW Speakers?

  4. Excellent site! Greetings from Canada. I also using a MC240 with Philips 7581A’s. Unfortunately last Sat. one of the 7581A red-plated. I can’t afford any of the NOS RCA’s etc. Would you say the Tung-Sol 6L6GC or 7581 or STR any good? Can I still use my three (less than 250 hours) 7581A’s with one of the Tung-Sol’s on the MC240?


    • Hi Len,

      Thanks for the kind words – appreciated. I like the new Tung-Sol 6L6G with the ST bottle shape quite a bit in my MC240. I haven’t tried the TS 7581 reissues, but you’ve got me curious about them. I’m using different 6L6GCs in my MC30s and they work fine, but I haven’t tried that in my MC240, but I don’t think it is an issue.

      If you decide to try the new TS 7581 tubes let me know you how like them. If I member correctly Jim McShane has them in stock.

      Kind regards,


  5. Hi Jeff,

    I have ordered last week the 6p3s-e and the Tung-Sol 7581A , the Tung-Sol have arrived and also installed yesterday in my Leben CS600. The 6p3s-e will arrive perhaps next Monday . I had no high expedation of the differences between the Sovtek 5881 and the Tung-Sol 7581A but I was wrong. The 7581A sounds much much much better in my system (ATC SCM40 v2) , the mids /high approaching the Apogee Minor speakers of my brother…..verry pleasant . The Sovtek sounds a little bit cold in my system.
    I have already listened to music from Frank Sinatra , Eva Cassidy, Dream Theater, Rory Gallagher , Wes Mongomery, Beethoven , Liszt, Glenn Hughes, Tom Ovans …everything sounds great.
    I curious how the 6p3s-e will sound.

    Kind regards,


    • Hi Ray,

      Thanks for the update on your findings on your CS600 tubes. I’ve there to be quite a range of sound you can get out of it depending on tube choice.

      There’s been quite a few positive comments about the Tung-Sol 7581A, I may have to give those a try in my MC30’s one of these days!

      I’ll be interested in hearing your observations on the 6p3se compared to theTung-Sol 7581A. Exciting!

      Thanks for the update, and I’m looking forward to hearing more!

      Kind regards,


  6. Hi Jeff,

    Perhaps its to early to comment on the 6p3se but they sound impressive even only after 5 hours playing. The Tung-Sol 7581A sound softer in the mids and has more energy in the lower octave but the 6p3se sounds more a live like.
    You are not familiar with the ATC speakers but its almost the same when you comparis the ATC with Harbeth sound. The Harbeth is very pleasant sounding speaker and sounds softer then the ATC.
    I can live with both of the speakers as can I with both of these type of tubes .
    Thanks for all the info on your website!

    Kind regards,


    PS: Do you know if its better to have a matched quad of the 6SC7 tubes, I thought because the Leben has an auto bias it doesnt matter or I am wrong.

    • Howdy Ray,

      Thanks for the updates! Both the 7581A and 6p3se sound like winners. I really enjoy the 6p3se, but your description about the 7581A sounds very interesting, I may have to give them a try too!

      I normally ask for matched tubes if they have them available, but you’re probably ok if they don’t. I bought a bunch of 6CS7 NOS when they were plentiful about 10 years ago, to get me through the years, and they were pretty easy to get in matched quads then. They turned out to be a very rugged and long lived tubes, so investing in good ones will last you many years.



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