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.
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!
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.
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.”
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.
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.
Below, a back view of the board for Yves’ restored MC30 amp.
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?
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.
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!
I’ll explain more fully about what exactly has been changed in my next post, and what it all does.
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.
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.
Now Ron and I decided it was time to do a little listening comparison to the two versions of the MC30 mono amps.
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.
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.
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.