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."

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.

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.

Western Electric WE16GA

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.

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

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?

http://www.spec-corp.co.jp/arizona/index.html

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!

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.

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.

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

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

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!

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!