Nattawut 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 and Sentimental Studio, 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.