May 132015

If you’ve read my review of the SPEC RSA-M3 EX Real Sound Amplifier in Positive Feedback Online in Issue 78, you know how interesting I found the high-fidelity adventures of Mr. Shirokazu Yazaki to be:

“I learned the audio lesson that while parts choice does make an important difference in performance, it is the ‘enlightened ear’ of the talented designer that determines the ultimate musical performance of an audio amplifier, whether it contains vacuum tubes or solid-state devices.

A case in point is the SPEC RSA-M3 EX Real Sound Amplifier from the ‘enlightened ear’ of Mr. Shirokazu Yazaki in Tokyo, Japan, that sounds shockingly good by any musical or sonic measure.

From the first moment that I saw, touched, and powered my hi-fi systems with Yazaki-san’s SPEC RSA-M3 EX Real Sound Amplifier I was deeply impressed with what he has accomplished. There is a certain irresistible ‘sensuality’ sonically, musically, and even visually to the SPEC RSA-M3 EX Real Sound Amplifier that makes it quite a captivating amplifier to listen to music with.

Before I get too carried away telling you about the SPEC RSA-M3 EX Real Sound Amplifier, let me back up for just a moment and tell you about the man behind it, Mr. Shirokazu Yazaki (second from the left in the photo below). I have found the story of Mr. Shirokazu Yazaki’s audio journey during our conversations to be quite fascinating, and I’m hoping I can relay that sense of intrigue to you, and why I think his story is important.”

64 Mr.-Sirokazu-Yazaki and the SPEC Team

I encourage you to go and read the review if you haven’t already, there’s lots of fascinating information in it, and you’ll get to find out all about why the SPEC RSA-M3 EX Real Sound Amplifier has become my reference solid-state amplifier.

61 SPEC-RSA-M3-EX-front

Since publishing that review, Mr. Shirokazu Yazaki and I have continued to correspond about our shared audio passions. During our conversations Mr. Shirokazu Yazaki shared with me/us here at Jeff’s Place about his very exciting discovery of the very ‘real sound’ of the vintage Western Electric WE16GA wire when used as speaker cables, and the ‘vintage-style’ Belden 8402 microphone cable when used as RCA interconnects, both of which he now uses as his ‘reference’ cables.

WE16GA 2

Western Electric WE16GA

Belden 8402 microphone cable 2

Belden 8402 microphone cable

I’ve built RCA interconnects with the Belden 8402 microphone cable and installed the Western Electric WE16GA as speaker cables, and I have been very impressed with both (as have been a number of you who have reported back similar impressions). These cables share a very natural and detailed sound, gorgeous tone color, and incredible timbral realism.

76 Mac equipment

Western Electric WE16GA speaker cables and Belden 8402 interconnects

Now once again from the ‘enlightened ear’ of the delightful Mr. Shirokazu Yazaki comes a suggestion for an intriguing audio adventure, a ‘Capacitor Adventure’ for one of my vintage McIntosh amplifiers:

Dear Jeff-san,

I have to talk to you. You said at the end of your latest blog post that it’s time to get out your soldering irons, and it gave me a new idea! (A reference to my blog post about making some vintage-style Belden 8402 RCA interconnects – Jeff)

Of course, I have much enjoyed your blog and saw your MC225, MC240, MC30 amplifiers. Yes I know, those are excellent vintage amplifiers. At the same time, I have experienced on many occasions that the capacitors for coupling use change the sound of tube amplifiers. So I would like to recommend that you to start a ‘Capacitor Adventure’.

I have long done research on the signal use capacitor to be able to realize my sound image for our low-pass filter of Class-D amplifier. And I came to the conclusion that the good sound capacitor for the low-pass filter could also improve the sound quality of a tube amplifier by using such a capacitor. And at present, fortunately I have access to Arizona Capacitors and our mica capacitors.

Over the time of my audio career and research it was very natural that I had a few chances to hear the sound of  the “Sprague Black Beauty Tone Cap” with its very attractive mid range (The original PIO BB is revered for its ‘magic tone’ and was part of the reason vintage Gibson electric guitars sounded so good – Jeff). But compared to old West Cap, hermetic seal military grade capacitor, I felt there was less clear high range for the Black Beauty, but also richer information for the West Cap.

West Cap has survived as Arizona Capacitors, Inc., and the quality of the Arizona Cap is far superior than even the vintage West Cap, so we started to sell Arizona Cap in our domestic market for tube amplifier fans in Japan just 4 years ago. Our line-up of Arizona Cap is composed of “Blue Cactus” and “Green Cactus” and each type has a special virtue or character.

Arizona Capacitors Blue & Green Cactus capacitors

Arizona Capacitors Blue & Green Cactus capacitors

You could see our line-up below and if you want to try it, I would like to send it as the sample to you. How do you think about the adventure?

Regards, Shirokazu Yazaki
SPEC CORP./ Engineering

I have learned it is very wise to pay attention to Mr. Yazaki-san’s suggestions, and I must say I was intrigued by his recommendation of a ‘Capacitor Adventure’ using one of my vintage McIntosh amplifiers.

My friend Ron volunteered to help me with the Capacitor Adventure (whom you are familiar with from other blog posts about vintage vacuum tube amplifiers here at Jeff’s Place). Thank you Ron-san!

MC30 Mac

McIntosh MC30 monaural amplifier

Ron and I discussed the merits of which vintage McIntosh amplifier to choose for the Capacitor Adventure, and we decided on the MC30 monaural amplifiers, with their simpler circuit, and vacuum tube rectification.

We let Mr. Yazaki-san know our choice of the MC30 monaural amplifiers, and he began to study the MC30 and think about a ‘capacitor kit’ that would bring out the best in its performance. (A big thank-you to Mr. Yazaki-san for his kindness in encouraging this exciting project! 🙂 )

Dear Jeff-san,

First of all, I would like to recommend to strengthen the power supply of MC30, and it could bring out the comfortable high speed sound in phase throughout entire range. Please refer to the attached file.

Capacitor Adventure schematic for MC30

An ideal capacitor have never been existing. Above all E.S.R (Equivalent Series Resistance) characteristics of electrolytic capacitor’s high frequency range are poor in general. But we must adopt the electrolytic capacitors for some power supply circuitry and this capacitor’s E.S.R is almost same as internal resistance of the power supply. In another words, the flow speed of electric current from the power supply owes to the E.S.R characteristics of capacitor.

Capacitor Adventure cap kit for MC30

Hermetic seal oil filled capacitor’s E.S.R. for high frequency is far superior than electrolytic capacitor and the parallel connection to the electrolytic capacitors could lead to improving the characteristics. And accordingly, the sound could be found more clear and richer. I have experienced so many times that when I load this type of oil filled capacitor just at the output of rectifier or diode, the sound improvement is remarkable.

And the parallel connection of multiple capacitors could reduce the E.S.R. It also bring to the high quality sound.

Regards, Shirokazu Yazaki

As we continued to discuss the Capacitor Adventure, Mr. Yazaki-san finalized his ideas to improve the MC30s’ performance.

Dear Jeff-san,

I will ship you your ” Capacitor Adventure ” kit this afternoon.

All of the parts, Arizona Cap, our mica cap, diode and resistor, are the best parts I have ever met. I hope you enjoy the adventure.

Mallory vintage electrolytic capacitors are included in the kit. I regard the capacitor as the benchmark of the sound
even at present. Arizona Caps are our full custom order parts to Daryl-san. Type C50309, called “Blue Cactus” has
a little bit the color of vintage American, close to old ‘West Cap’ for military. But Type C50313, called ‘Green Cactus’ has the
sound of radically new for the hermetic capacitor, very wide range and outstanding fine tone.

I think all of the capacitor, except excellent mica capacitor has some tonal bias and so we had better to blend a few types of capacitor to get the favorite sound. Please try them!!

And I also include the wire vintage Western Electric 20GA single cable for wiring. It might be best for wiring of tube amplifier. The cable is the remain one of Ookubo-san’s DA30 SET amplifier.

And you could see the circuit of your new MC30 in attached file.

Regards, Shirokazu Yazaki

Cap Adventure schematic - 1

Mr. Yazaki-san’s circuit suggestions for the MC30 monaural amplifiers

Cap Adventure schematic - 2

Mr. Yazaki-san’s suggestions for the MC30 circuit

Well it certainly is exciting times here at Jeff’s Place, and I am thrilled about Mr. Yazaki-san suggesting the Capacitor Adventure for my vintage McIntosh amplifiers.

When I got home from the office there was a package from Mr. Yazaki-san – the Capacitor Adventure kit has arrived!

Capacitor Adventure kit arrives at Jeff's Place

Mr Yazaki-san’s note made me smile. 🙂 Many thanks to Mr. Yazaki-san and Ron-san for making the Capacitor Adventure possible!

More soon!

Thanks for stopping by!

 Posted by at 5:17 am

  16 Responses to “The Great Capacitor Adventure! The aroma of solder is in the air!”

  1. Kaizen in action again.
    Devil is in the details!

    I once found a tiny length of exposed wire was picking up hum-very noticeable on my then speakers , Klipschorns.
    Flying leads sorted it.
    So caps should certainly have differing effects.

  2. This sounded familiar, didn’t you speculate about cap rolling in one of your Omega reviews? I think that was one of the first Omega review I read.

    • Hi Mark,

      It’s possible I did, maybe for an Almarro amplifier? I still have the original Almarro EL84 integrated amplifier that I wrote about for 6Moons many years ago, and it is a wonderful amplifier.

      Rolling caps allows for a rather dramatic amount of tailoring of the sound. The changes Yazaki-san recommended for the McIntosh MC30s were a real ear opener, and took Yves’ already great sounding MC30s to level that deserves a story all of its own.

      All I can say the Arizona Capacitors Blue & Green Cactus capacitors are amazing, and the way Yazaki-san recommended we use them is very intriguing. Ditto for the SPEC ruby mica capacitors.

      Much more to come on this topic!



  3. Jeff,
    As usual, great article. You have a nice way of making your excitement about your stereo adventure come alive on the virtually printed page. I’m particularly interested in this chapter because I’ve got a pair of MC30s that I’m in the process of collecting parts for and restoring. Would you mind sharing the parts list that you got from Yazaki-san? The Arizona caps don’t seem to be sold by the normal distributors in the US but they are willing to sell direct to the DIYer if you meet a minimum order.
    Thanks in advance,

    • Hi Gary,

      Thank you for your kind words, I really appreciate it.

      I have been intending to share Yazaki-san’s parts list, but time has gotten away from me a bit – sorry about that.

      I’ll be working up a post with the parts list in the near future (I hope!). Also, Arizona Capacitors is trying to figure out how they can make the capacitors available more easily, which I’ll post about as soon as I know more.

      More to come.



  4. Hi Jeff
    I have been following with intrigue, to this has Arizona capacitors figured out some sort of distribution for the above-mentioned capacitors?

    Keep on Blogging

    Kind regards

  5. What are your experiences with laying a sound arizona cactus capacitor?
    After how many hours of sound began to like?

    • Hi Chris,

      I’ve had good results with the Arizona Capacitors in my vintage McIntosh MC30 monaural amplifiers, and the crossovers of my Altec A5 crossovers, but not so much in my vintage McIntosh MX110Z tuner-preamplifier.

      I prefer the tonal balance of the new Duelund CAST tinned-copper capacitors by a huge margin to the AZ’s, as they’re a better match to my system & tastes, and I hope to share more information about the Duelund’s as I try some more modifications with them.

      I should say that all my experience at the moment is with the prototype Duelund CAST tinned-copper capacitors, and as I get some experience with the productions versions I should be able to say even more. The prototype versions, quite frankly, are stunning in every application I’ve tried them in.

      The only caveat with the Duelund CAST tinned-copper cap’s is their size, they’re big, about twice the size of the AZ’s, so you’ll have to make sure they’ll fit in the application you intend to try.

      Kind regards,


  6. I tested it as the (50 h – first capacitor of 5U4G rectifier) ​​Arizona Cactus Blue, Green, Red and I have already formulated opinions.
    All Arizona Cactus are very good but the blue cactus is quintessential of music, music, phonophony, engaging the listener, engaging in musical spectacle. This capacitor causes each disc to be reproduced in a very realistic, real, analog way.
    Green cactus is not a good solution in this place, because it is all conquered, tied up and resounded with a lot of power – that’s not what I mean.
    The red cactus sounds slim but it is the perfect complement to the blue cactus, although the blue cactus itself is sensational.
    Ideal capacitor 10 (Duelund!?)
    Blue cactus 9,
    Gree cactus 8
    Red cactus 8,5
    Now time for duelunda just do not know who?

    • Hi Chris,

      Thanks for the report!

      I haven’t yet done any further capacitor modifications on my MC30’s. I’d really like to try the Duelund CAST tinned-copper capacitors in my MC30’s one of these days.

      In my MX110Z preamp the Duelund CAST tinned-copper capacitors were at another level above the AZ cap’s, it wasn’t even close. The Duelund’s are amazing capacitors in my MX110Z!

      Let me know if you decide to try the Duelund’s, I’m really curious about how they will work in the MC30’s!

      Kind regards,


  7. I happened to stumble across this article and your other entry about Tepco, AZ capacitors, et cetera and want to say thanks.

    I’m building my very first vacuum tube amp and the more article the better. I’m learning a bunch and am also terrified I’m venturing down the road of expensive parts… but it’s a good thing.

    Not sure any of this make sense but, yes, thanks for all of the reference material. Keep ’em coming. 🙂

    • Hi Bob,

      Thanks for the comment and kind words, both appreciated!

      Have fun, and be sure to let me know how it all works out.

      Kind regards,


  8. I currently am using the Pure Audio Project Speakers with dual 15 inch neo woofers and the Excellent Voxativ driver from 350 hz on Up . The speaker uses just one capacitor, to the Voxativ a huge 68uf Clarity new – CSA capacitor very well balanced
    Better then the Mundorf Evo . To make this special we added the Excellent 2.2 Jupiter Copper bees wax cap,and the 1 uf blue cactus oil cap . Fantastic the Jupitersometimes is over looked .personally the jupiterbetters the Duelund cast in the midrange in detail and with the Blue cactus a incredible combination . Even with this big Clarity cap you hear all the attributes of the other 2 caps I am now using the blue cactus on all my Mundorf 4 pole caps in the PS and a .22 on the output of myDHT preamp. A word to the Wise donot underestimate the Jupiter Copper the only thing personally I wanted a bit more of was warmth
    Now you have the Cactus Blue for added warmth ,depth and 3 dimentiality. To me the best cap combination to date !!

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