Akarakrit Uamkruea, blogger and audio gear maker who passionate in vacuum tube, audio & music.
Producing electronics projects since high school. Seriously upgrade and modify vintage audio equipment for “Real Sound” concept.
He is a co-founder of Soundaries, all audio solution provider.
Experienced and lively explore the listening rooms & audio shops in Japan as his most favorite to do.

Monday, May 30, 2016

Visit Mr Shirokazu Yazaki's Audio System

Last 2 weeks, I just came back to Tokyo again with plan to visit Mr Shirokazu Yazaki's home

to listen his audio system after he had invited me in last time.


I feel excited that I'm going to hear and see his audio equipment.

Because I want to know how he's train his ears for tuning all "SPEC" products.

And all of products designed with intention both electronics & appearance.

I just met him at old SPEC office and take the train to his home in west side of Tokyo.

His system use bi-amp with DA30 tube amp for mid-range horn & tweeter 

and prototype class D of SPEC amp for woofer. 

In his speaker system, he's use Altec 414 woofer in old Coral cabinet,

mid-range driver is Onken 500MT with wood horn and Onken 5000T tweeter.

All speaker wires using WE16GA from Western Electric.

Pioneer digital players and Marantz model 7 with "Real Sound" modification 

that I follow in his footsteps.

His own DIY tube amp with WE310A as driver and DA30 for power tube 

with shoot-out some of 5U4G rectifier tubes in that day .

Replace and test some of them for find out each own taste.

Prototype of class D SPEC amplifier for low frequency driver.

Many experiments inside.

Yazaki-san describe how to tuning capacitor in output stage.

Nice dessert from his wife, thanks Yumi-san for her warm welcome too.

Thanks Yazaki-san again for his time to made a magic moment with his audio system. 

And more valuable knowledge from his ideas and action.

His system present as he did with all of his products.

Dynamic, speed, detail and tonal balance can describe only one word.

"Real Sound" is all good listeners need.

Hope to come back to his home again soon. 

Beautiful flower in front of his lovely home.


  1. Hello. Can you send me Onken OS-5000T frequency and impedance responses?

    1. Will check and let you know after I get more information.

    2. Did you check this?


  2. Hi, I have been following your fantastic guidance within my own system. Most recently I have installed some of your excellent Arizona Cactus blue capacitors (0.47uF 600V) and after they have finally run in and settled (about 120 hrs) they are incredible, to be honest I was a little concerned they were not really ever going to open up in the LF but wow they have now!

    I have a final output coupling cap that I want to replace, it is 1uF and has a 180V DC component across it. My question is does the 200V 1uF sound the same in power and fidelity as the 600V 0.47 uF or would it be better to run two 0.47 uF in parallel if I can fit them in?


    1. Hi,

      You can use 1uF/200V at 180V point without any problem.

      But you can mix 0.47uF Blue & Red Cactus together for more exiting sound.

      Wait to hear your result.

      Best regards,

  3. Thanks for the reply.

    An interesting idea to try the Red with the Blue. What I want to do is to make sure I don't loose the power, dynamics and speed in the bass and low mid. My system (old ARC SP8 and a SE 211 amp with Klipsch speakers) is sounding great with these new Arizona caps, and I wanted to make sure I don't loose any power with the last capacitor change, if the 200V is the same sound as the 600V then I will start there.

    Out of interest what would the red+blue have as a sonic signature or is that impossible to say!

    I will come back to ask for more guidance when I start improving the 211.

    Can I share photos here at all by the way?

    1. Yes, you can share every good things here.

      Red+Blue will improve high frequency response.

      But if you happy with Blue's tone, you can use single 1uF as you've mention.

  4. Oh, another quick question do you have any recommendations on cathode bypass capacitors, I have a 100 uF, 100V on the 211 amplifier I have.


  5. Thanks for guidance on 100 uF

    I also have these on my list
    Wet Tantalum HI-TMP®
    Elna RFS silmic

    RIFA are coming out as 15 years old and sat nest to a hot power resistor!