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, August 5, 2019

Fantastic Feastrex Speaker Experience

Yamanashi is one of beautiful prefecture in Japan.

Not far from Mount Fuji and has many great fruit farms that so interesting.

Feastrex company located near the mountain in Nirasaki city.

The owner, Akiyama-san also do business with forest and rare mushrooms too.

He is smart guy and has so many special knowledge especially electronics & music too.

Feastrex word came from "Feast" that mean Celebration and "Rex" that mean King.

So "Feastrex" mean Celebration of the King!

Main specialty of Feastrex is field coil electromagnet speaker and only single driver

fullrange speaker in bass reflex cabinet.

You can see his website here

In my opinion, sound of this system is nice transient, dynamic with minor detail

and tone of every music instruments are real & joyful cause from missing crossover network.

Compare with his AlNiCo version, field coil easily won in micro details & sound stage

but AlNiCo still better than others in fullrange league.

Nice experience for me and my Japanese friend : Kubota-san.

Got more ideas and techniques back home. ;)

Main room with many speakers.

Prototype speakers & parts. 

Beautiful cone from "Washi" paper.

Interesting audio system!

EMT-930st, very nice quality and sound.

Sony SACD player and custom preamplifier.

CV4055 Push pull tube amplifier with all FineMet core transformers.

Field coil power supply with FineMet core transformers & chokes, film capacitors and SiC diodes.

Special parts wait for using.

Fantastic craft work for wood cabinets. 

Nice cross section of Feastrex!

Akiyama-san explain techniques to my friend Kubota-san.

Memorial picture of us!



  1. Hi, spent some time visiting your blog. Very nice and informative. Added to my blog list as a must read about one year ago. Keep feeding us with nice posts.

    1. Hi Fred,

      Thanks a lot for your kind words.

      I also follow and read your blog for a long time too.

      Thanks again for sharing many great projects too!