Tube Amp
Custom-made vacuum tube amplifier

Power:2A3
Driver:6SL7
Output:3.5W
Distortion ratio:5%

Power:2A3
Driver;6SN7
Output:4.5W
Distortion ratio:5%

Power:2A3
Driver:6SL7
Output:3.5W
Distortion ratio:5%

Power:2A3
Driver:6SL7
Output:3.5W
Distortion ratio:5%
The original vacuum tube amplifier can be yours. Would you like to listen to
your favorite music with one of kind amplifier? The vacuum tube amplifier
provides warm sounds that cannot be reproduced with IC.
If you would like to have one, please order from PRODUCTION REQUEST FORM HERE
You might imagine a special sound system room when only hearing of a word,
“audio” such as an amplifier and a huge speaker with millions of power
consumptions, and a set chair for a preeminent listener. Generally people
hardly are familiar with audio because of this kind of images. ok this story
could connect to the discussion so called “Mania” so it had better no to
speak further than this. Of course, there is a feeling of envy toward the
professional area...However, real music is in our dairy lives. So, the audio equipments also should be in the daily life. Here is a suggestion of listening to music in your family house with your family members. It may causes good conversation and relationship in the daily routines. For example, kids finishing home works talk to their mom washing dishes at a kitchen, “ Wow! Listen! It’s cool here the sound in flat 5.” It is also nice to have good music closer and in relax.
THE VACUUME TUBE IS A CULTURE
According to Henri Bergson, civilization is for pursuing ease and
convenience and culture is emotion and/or affect. When vacuum tube was
appeared 100 years ago, it was about a civilization.
The technology has been advanced, such as the invention of the semiconductor
and digital technology with development of the civilization.
In fact, today’s audio equipment is rarely broken down, are low producing
cost (= large profit margin), are low electronic power consumption, and has
no distortion in the shape. It seems so perfect.
However, please wait a minute and think...
There was the moment that the vacuum tube turned into culture when it was
admired as the useful audio equipment. Civilization is logical. Culture is
emotional. Although they are continuous, in transferring process from logic
to emotion, the material object or the concept should be exact and
beautiful.
Each model of vacuum tube has each different story, such as for the
industrial use, household use, military use, HiFi use and so on. We can
expand our imagination over the histories of inevitability of the invention
and the desire/passion of the engineers who invented the operation circuit
systems. Fortunately, I got opportunity to fix an electronic phonograph
that was made about 80 years ago. It was wonderfully recovered by a little
touch of repairing. How do you think about if your High technological PC
will be functional after 80 years?
It is not exaggeratedly said that lots of amateur engineers’ passion have
supported the vacuum tube to survive in that form by today even it had been
disappeared from the industrial world.
It is possible to audition at lodge Grands Charmoz. Please feel free to come.
EL156 (china)-KT88 CONVERTIBLE AMPLIFIER:
This vacuum tube, EL156 was designed for the output of record cutting
machine of German Neumann, which is marvelously powerful tube with 50W of
the plate loss. When I got this ball (though it was not Terefnken’s
original made, but China-made), I was really looking forward trying to
listen to the sound, and searching a transformer to fit for it. However the
machine for driving it was little expensive, so I was concerning. At that
moment, I accidentally found an amplifier KT88 on a self in my garage, which
I made 30 years ago. I looked at the transformer, and realized Lax was used.
In those days, the transformer was about 2,000 yen, and it would be ok. A
spare of a single amplifier 2A3 produced by the request of Mr.O living in
Kanagawa was used for the chassis. I could not wait for putting them up with
drawing up the plans, so I completed them up with only the character table
of the vacuum tube.
Because KT88 was still remained getter at that time as well as it was a ball
of GEC, I decided to make it as use of convertible amplifier by making the
switch circuit of the cathode resistance. There was no faulty wiring, and
the sound was come out with ITAKE. Although it was made for me without any
big consideration, it became satisfied one even if connecting to the 94dB
speaker without any trouble of residual noise. It was so nice with the sound
of piano and high hat cymbals.
PREAMP EQUIPED WITH LM1036 (SEMICONDUCTOR COMPANY):
This is a pre-amplifier used the electronic volume chip named LM1036 made by
semiconductor company. Recently, it is difficult to get good quality dual
volume that made me little worry. In that time, I found this chip, and
challenged making one with it.
The case is original with coating of burning paint spcc1.6mm. An order made
amplifier was made by the request of Mr. T (living in Tateshina), on which
an equalizer amplifier was built for being able to listen to records as well
as installed the terminal RECOUT PLAYBACK. Also, another one with the tone
control circuit is used by Mr.F (living in Ome).
6L6-GC WOOD BASE AMPLIFIER:
This amplifier is made by the suggestion of a professional jazz bassist,
Tetsuo Miura.
Because I got Hammond’s output transformer, it naturally became 6L6pp. It
is connected to the end step with division P-K and the first grade 6SL7
(tone control) phase reversing 6SN7. It might be interesting to replace to
EL34.
However, unfortunately I don't have a wood base for the sound
examination, so waiting for the visit of Mr. Miura.
Lately, for the refinement, it has regenerated to the phase reversing of the
Murard type because of the problem of falling gain in the P-K division.
Furthermore, it was improved by deepening NFB to earn DF.

Before
the phase was crrected (left) & After
the phase was corrected (right)
