May 222015

The first step in our capacitor adventure was to dismantle my McIntosh MC30 monaural amplifiers and take a look inside at the very nice handiwork of Mr. Yves Beauvais. I purchased my MC30 monaural amplifiers at Yves’ retail asking price through his Vintage Vacuum Audio business.

Be sure to check out the accompanying links about Yves, you should know that he’s famous outside of audio for his work in the record business, where’s he’s produced hundreds of records.

Nude MC30

Yves is a very talented man who knows the sound of music from its origins in the recording studio all the way to its final product as an LP. Or in other words, we’re damn lucky to have someone with both the music biz experience and enlightened ear of Yves Beauvais that has a passion for rebuilding vintage McIntosh amplifiers with an ear towards the real sound of music!

MC30 with Western Electric wire

We pulled out all the tubes, then removed the six screws that hold the bottom cover of the MC30 on, and took a look inside. The first thing Ron noticed was that McIntosh MC30 monaural amplifiers are wired internally with Western Electric wire (check out the photo above), which is great sounding wire, as those of you know who have been reading my blog posts about the Western Electric WE16GA, and vintage Western Electric wire is what Mr. Yazaki-san uses as his reference.

MC30 with Yves' choice of components

The next thing we noticed was Yves’ very nice choice of components & excellent workmanship for the electrical restoration of the MC30s. In my ‘The Vintage McIntosh Experience’ article that I wrote for Positive Feedback Online, I said:

“For the electronic restoration, Yves rebuilds the power supply using a new multi-section twist-lock capacitor (the metal tube that sticks out from MC30), and replaces all of the coupling, bypass, bias voltage, and negative feedback circuit capacitors with new caps like Sprague Atom electrolytics, silver micas, and a combination of polyester (Mallory 150 for bypass) and polypropylene film (STKs), and a particular polypropylene cap that Yves says are faithful to the vintage Mac sound “without unpleasant mid-range boost.” Yves doesn’t like to use new old stock (NOS) caps because of the obvious hazard issue old caps pose, and instead he prefers to use new caps that “stay faithful to the beloved vintage tone.” Yves checks all the resistors and replaces them if they are off by more than 5%. Yves says, “Usually all or most resistors are replaced, with a combination of carbon comps and metal film depending on circuit location, in order to maintain tone (carbon) and reduce noise and distortion (metal film).” Yves says he has been investigating using tantalum resistors and may offer them as an option in the future.”

MC30 with Yves' choice of components 2

What all that means is that Yves’ choice of components was really nice, with an ear towards great sound & music making ability, and reasonably similar to what Mr. Yazaki-san proposed for our Capacitor Adventure.

MC30 with Yves' choice of components 3

Ron and I pondered what this meant for the Capacitor Adventure. Given the excellent quality and similar nature of the parts choices we wondered if we would even be able to hear a difference.

MC30 with Yves' choice of components 4

Below, a back view of the board for Yves’ restored MC30 amp.

MC30 with Yves' choice of components 5

I must admit, modifying my Yves Beauvais restored MC30 monaural amplifiers gave me a bit of trepidation. The thought of modifying really great sounding amps like these restored MC30s had me a little worried. What if we couldn’t hear a difference? What if it sounded worse?

Ron desoldering an MC30

Well, daredevil that I am, I decided to plunge off the deep end and give it a go. Above is Ron-san starting the desoldering process.

Below is the ‘capacitor kit’ Yazaki-san put together for the for the MC30. The parts in the photo are for one monaural MC30, so its double that for the pair.


Ron at work

Just so you know, this is a significant amount of work to do. Desoldering everything that needed to be removed, doing the layout for the changes, installing all the parts that Yazaki-san sent us, measuring all the parameters, and testing the amp to make sure it was doing what it was supposed to, I’d say Ron-san put in approximately 18 hours to do the upgrade for one MC30 monaural amp. The second amp will probably go quicker now that Ron knows all the ins and outs of what to do and expect, but it was a lot of work.

Here’s what my MC30 monaural amp looks like after Ron-san installed everything from Yazaki-san’s capacitor kit (below). The MC30 in the foreground is my Yves’ restored MC30 with Yazaki-san’s capacitor kit installed by Ron-san.

By the way, Ron-san did an absolutely beautiful job on it! Thank you Ron!

Yazaki-san capacitor kit installed in the Yves MC30

I’ll explain more fully about what exactly has been changed in my next post, and what it all does.

Yazaki-san modification 1

Yazaki-san modification 2

Yazaki-san modification 3

I’ll provide you a list of all the parts involved in the upgrade, and how much they cost as soon as I can get all of the information together. Some of them are a bit spendy, others not so much. It may take me a while to pull the cost information together, so be a little patient with me on that front.

Yazaki-san modification 4

Yazaki-san modification 5

Yazaki-san modification 6

Yazaki-san modification 7

At this point we have one monaural MC30 as restored by Yves, and one monaural MC as restored by Yves, but with the capacitor kit (resistors too) installed by Ron according to the schematics below from Yazaki-san. The red & green notations are the changes Yazaki-san’s capacitor & resistor kit made to the circuit. Again, more soon on the why of those changes.

Cap Adventure schematic - 1

Cap Adventure schematic - 2

Now Ron and I decided it was time to do a little listening comparison to the two versions of the MC30 mono amps.

System photo

We wired up both of the Westmonster speakers (that’s what Yazaki-san calls them, and it always makes me smile) to the Yazaki-san capacitor kit MC30 (using the 4 Ohm tap), switched the MX110Z preamp into its mono setting so we could run a single interconnect to the amp, and listened to some music.

Yazaki-san mono

We listened to Masterpieces by Ellington, my Analogue Productions test pressing of Miles Davis’ Cookin’, the Cowboy Junkies’ The Trinity Session, and Julie London’s Julie is her name, to get a listening baseline.

Yves mono

Then we put the Yves’ MC30 mono in and listened to it through the same sequence of music, and then put the Yazaki-san MC30 mono back in the system and listened again.

A few observations: First of all, the Yazaki-san modded MC30 may be the best sounding amp I’ve ever heard, at least from the mid-range on up. There’s still a bit of that classic ‘tube bottom end’ present I think, but I’ll know better as everything runs-in, and I’ve got a stereo pair to listen to.

Yves’ MC30 restoration sounds great, but it was clear to Ron and I that Yazaki-san’s modifications took Yves’ MC30 an astonishingly high level of performance that put it in another league. I guess we needn’t have worried about whether we could hear a difference or not.

I’ve never heard heard Miles Davis’ muted trumpet sound so utterly real and natural as it did through Yazaki-san’s MC30. The same was true of Margo Timmins’ & Julie London’s voices, they were utterly natural, with no unnatural sibilance, and an astonishing amount of presence. Masterpieces was freaky good.

If you just listened to Yves’ MC30 you’d be happy as a lark (just as I have been), until you put on Yazaki-san’s modded Yves MC30 amp, that is. In comparison Yves’ amp sounded a bit edgy on vocal sibilants and muted trumpet. It wasn’t as rich and elegant sounding. It was not as timbrally convincing. Don’t get me wrong, Yves’ MC30s are amazing, but they’re taken to a whole new level of amazingness with Yazaki-san’s modifications.

The Yves MC30 with the Yazaki-san modifications sounded elegant, rich, utterly natural, timbrally correct, with gorgeous tone color, and a mesmerizingly musical presentation.

Ron and I were both really wowed by the transformation wrought upon the already very good Yves MC30 amp by the Yazaki-san capacitor kit. Ron-san was wowed enough that he scooped up the non-modded Yves MC30 along with the Yazaki-san capacitor kit and raced out the door so he could get some soldering time in on the second MC30 before the day came to a close.

I’ll have a lot more to say as we get the second amp up and running, and get some more time on the new components.

I’ll tell you what, both Ron and I are convinced that Yazaki-san is a true audio genius. Yazaki-san looked at the schematic for the MC30, and based on his long experience in voicing electronics, he picked out some key components to change, put a kit together for us, and the result has been a real ear-opener!  Truly Yazaki-san’s parts choices and modifications turned the MC30 into a ‘real sound amplifier’ with a beauty, tone color, timbral naturalness, and rich musicality that is simply stunning. There’s no other way to put it, the result is brilliant!

A huge ‘Thank you!’ to Mr. Yazaki-san for suggesting a Capacitor Adventure and making it happen.

An equally big ‘Thank you!’ to Ron-san for donating so much of his precious time to rebuilding the MC30 amps.

Yazaki-san and Ron-san are two truly awesome gents that I am pleased to be able to call my friends.

The combination of Yves’ MC30 restorations with Yazaki-san’s capacitor kit, and Ron’s talent in putting the two together, is simply amazing, a true capacitor adventure just as Yazaki-san said!

I’ll have much more to say as things progress a bit more.

 Posted by at 6:37 pm

  23 Responses to “The Great Capacitor Adventure! Part Two.”

  1. Thanks for documenting the adventure with your photographs and words. You made a brave and bold move to modify a restored classic amp. Do you intend to do something similar with your other McIntosh stereo amp? Obviously, Yazaki-san understands the sonic signature of vintage McIntosh amplifiers and the Arizona Capacitor products to properly voice your amp.

    Earlier this year, the Science Channel’s “How It’s Made” program featured the manufacture of today’s version of the McIntosh MC275 stereo tube amplifier. Although it is great to see how this amp is made using today’s manufacturing technologies, looking at Yve’s and Ron’s work gives me a greater appreciation of how things were made. The modern MC275 features printed circuit boards rather than point to point wiring, and the components used are not even close in quality to what is in your amps.

    • Hi Rich,

      Thanks for the kind words – appreciated. 🙂 Thanks for the tip on the ‘How It’s Made’ program on the MC275, I’ll see if I can find it and watch it.

      When Ron, Leo, and I got together for a listening session yesterday to listen to the stereo pair of MC30s (Ron finished up the second MC30), Leo asked me exactly the same question, and it’s tempting to continue the adventure with the MC225 Mac that was restored by Yves. I’ll have to think about it though, and of course Ron would have to want to do that, as it’s a significant amount of work time-wise.

      I should say that being able to start with something as superb as Yves’ McIntosh MC30 restorations is really a treat. It feels a little bit sacrilegious to modify them, but the results were impressive.

      Yazaki-san has mentioned some other ideas he has been thinking about for the MC30s, so there may be more to come from the enlightened mind of Mr. Yazaki-san, which if you’ve been keeping track, his suggestions have always spot-on, so that’s exciting.

      Also, Ron mentioned modifying the MC30s’ chassis to install Oyaide Power Inlet Rs as suggested by Mark Coles to me a while back. Mark’s Sablon Audio power cords provide a huge performance upgrade over stock captive cords like the vintage Macs have, and I’ve really missed being able to use them on the Macs. So that’s definitely something I’d like to do. In fact, that reminds me that I’d better order a pair.

      The results of Yazaki-san’s Capacitor Adventure have been so impressive that I think I’m going to follow up the blog posts with a full article for Positive Feedback Online at some point in the future. I’d really like to be able to describe in detail the story of Yazaki-san’s Capacitor Adventure, his suggestion of using a blend of Arizona Capacitors (formerly known as West Caps), Yazaki-san’s SPEC Ruby Mica capacitors, the Ohmite resistors, etc., and a detailed analysis of the Yazaki-san upgrades to the Mac’s circuit and his rationale for the changes, and why they made so much of a difference.

      More to come!



  2. I was never a huge fan of the Russian military-grade K40y-9 Paper-in-Oil (PIO) capacitors. To my ears, the midrange tone is slightly off, and the amps I’ve heard with them installed as coupling capacitors and power supply bypass capacitors have an edgy treble as you’ve described. They are inexpensive and there are eBay sellers in Eastern Europe selling them all the time.

    • I’ll tell you what, Rich, these Arizona Capacitors (formerly known as West Cap), the SPEC ruby mica caps, and the Mallory caps suggested by Yazaki-san are really a nice sounding combination.

      I really like the way Yazaki-san blended the sonic & musical characteristics of the Blue & Green Cactus, Spec ruby mica caps, Mallorys, Ohmite Brown Devils, etc., and the result is really spectacular.

      I’ve been enjoying a cup of coffee this morning while listening to jazz through the modded MC30s, and they seem to be getting better by the hour as things run in a bit.

      I knew the MC30s were really great amps, but I had no idea what these MC30s were really capable of until we installed Yazaki-san’s capacitor kit. I think there’s a few more things coming too, which is really exciting.

      Thanks for stopping by!



  3. Perhaps you can talk Ron-san and Yazaki-San into helping you with retrofitting your MC-225 as well. You know things are really gelling with your system when you start spinning disc after disc just enjoying the music.

  4. I second the idea of Yazaki-san’s ideas about retrofitting an MC-225. What’s the protocol about informing Yves about these mods? I wonder what he would think of them and whether he’d be willing to incorporate them into future restorations.

  5. Hi Jeff,
    I know nothing about the guts of electronics and still I find your evolving story continuously fascinating. First with the Dueland crossovers and now with the MC 30 mods. My obsession with our hobby has me reading a lot of material from all over the web every month as well as subscription hard copy. The anticipation I have experienced waiting for your installments is unique and I thank you for that.

    • Thank you, Mike, for the encouraging words – appreciated. It’s amazing how much of a difference both the Duelund CAST crossovers made to my WRSEs, and the Yazaki-san ‘capacitor kit’ made to the MC30s. Really good stuff!



  6. Jeff-san,
    My capacitor adventure has begun! Yazaki-san just e-mailed a revised circuit diagram for my Audio Research SP-6C pre-amp with a list of parts, many of them Arizona Capacitors, with more information to come.

    In the meantime, I am thoroughly enjoying my Omega Alnico-Decware Zen-WE16GA rig since I first turned it on last week. A full A-B comparison with my modest but fundamentally musical PSB desktop system would be nonsense, but I can describe it with a photographic analogy: it’s like looking with a naked eye at a contact print of a well-exposed 35mm negative, then looking at the same negative enlarged to an 8.5″ x 11″ straight print. There’s much more detail and the gray scale dynamic range is wider and far more subtle than you could ever see in the contact print, even with a magnifier. And still no grain.

    Speaking of wide and subtle dynamic range, another mono title I’m sure you’ll enjoy if you haven’t already is Miles Davis and Gil Evans’s “Birth of the Cool”. Some solos end as two-instrument chords slowly rise from black until they nearly match the level of the solo, which then drops to the level of the backing instruments to form a triad. Like watching the last ingredient melt into a sauce. Magic.

    Enjoy the weekend; may your music be sweet & soulful. And thanks again!

    • Hi Mark,

      Congrats on getting started on a ‘capacitor adventure’ with the AR – you’ll have a blast!

      I’m glad you’re enjoying the new Omegas & Zen amp, it sounds like a great combo.

      Keep me posted on how your adventures are getting along!



  7. To Mark Paul
    I would really appreciate a forward of Yazaki-sans information on the SP-6c as I have one which has never been molested and is in need of attention. If you could share the parts list in particular it would help motivate me to unpack the preamp and embark on yet another adventure. Good luck modifying the Audio Research.

  8. To Ron Barbee—
    Yazaki-san tells me there’s more information to come, so when it’s complete I’ll be happy to pass it along. (Send an e-mail to me at mark-paul [at] so I know where to send it.)

    Mine too is stock as new so there shouldn’t be any problems. Yazaki was very positive about the circuit design and ARC’s general selection of parts. I’m really pleased to see a possession bought new has become a vintage classic. I think the preamp has aged better than I have.

    May your weekend’s music be sweet & soulful—

  9. Jeff,
    with great interest I have read your articles on vintage McIntosh gear – and couldn’t resist pulling my MX110 and MC-30s out of storage. They are connected to a pair of Tannoy Arden and I really love that combo – especially after beginning to upgrade the power amps along the lines of your capacitor adventure. I contacted Arizona Caps and they put me in contact with their German supplier – and – as a generous exception I guess – I shall be getting some caps for this mod. What I have aready done is adding two PIOs to the power supply – the result is indeed stunning (as indicated by Mr. Yazaki-san). So now I am waiting for the Arizona Caps – if they are as fabulous as you suggest, I shall be extremely pleased.
    Anyway, thanks a lot for your great website – I enjoy browsing a lot and hope to read more about any changes to your McIntosh gear.


    • Hi Wolfram,

      I’m so glad you got out your MX110 and MC30s, I’ll bet they sound great with the Tannoy Arden loudspeakers.

      If you haven’t tried the Western Electric WE16GA wire as speaker cables, and the Belden 8402 microphone cable as interconnects, you’ll want to give that a try too, as they also provide wonderful results.

      Keep me posted on how your MC30 mods turn out. I suspect you’ll be really pleased. 🙂

      Kind regards,


  10. I have been following your MC-30 upgrades for some time now and it, inspired me to purchase a pair of MC30’s.
    Got them up and running and they are fantastic,
    I now want to dive deep into doing the same upgrades you mentioned in the kit.

    Have you completed the parts list yet?

  11. Jeff,

    Thanks for sharing your vintage McIntosh stories. I just bough a pair of MC30 from Yves, and man, you are right about those old Mc. I sold my 2015 MC75 right away and never looked back! Yves told me vintage MC75 would sound similar to MC30 but with more authority, and he never a big fan of MC60. Well, that is hard to believe because just base on the power and rectifier tubes used in MC30, MC60, and MC75. What do you think about vintage MC60 and MC75, are they worthy buying? BTW, the little MC30 did wonderful job driving my Tannoy Turnberry in bass.

    Best regards


    • Hi Griffin,

      Congrats on your MC30 amps, they are really something special!

      I haven’t tried the MC75 or MC60’s, so I can’t say much there, but the MC30’s are so good I’ve never been tempted to replace them with anything.

      It’s kind of a shock to try a pair of the ol’ MC30’s and find out they run circles around pretty much everything else musically & sonically.

      If you decide to go for the MC60’s or MC75 be sure to let me know how you like them!

      Kind regards,


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