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| Sansui Tube Amps Restoration Project Done by Mr. Dirk Neudenberger in Germany
Before Restoration Photos:
Dirk Wrote on 04/09/2005: The transformers are much more huge like on the picture of the
side view that is why the scanner puts its focus on the tubes in the fronts. Dirk Wrote on 04/10/2005: I just took off the output transformers of my mysterious
Sansui Mono-blocks.
After Restoration Photos:
Dirk Wrote on 06/17/2005:
Sansui B705
Main Transformers are used on this amp. The Power Transformers are
"P70B". The required tubes per mono-block are 1x 6sn7GT, 2xKT66/EL34,
1xGZ34.
This is a
simple but good layout. An Eizo HF87 or Dynaco 70 does nothing better...
I
will have to replace the old Spraque/GE electrolytic due to some hum of both
amps.
(The amps work
good now, sound nice, but the caps have to be reformed or better
replaced....)
If anybody has
additional information about the purpose or data of these unique amps, I
would be very thrilled to
getting these
news...
Dirk Wrote on 06/28/2005: Maybe these are the oldest still existing and working Sansui mono-tube amps.
Now I have replaced all
electrolytic caps with similar looking German "F&T-brand" 2x50uf and
2x15uf caps.
, so the hum almost
disappeared, but to get it dead-quiet, I will have to modify the heater
circuit with one or two anti hum regulators.
I would love to get more
info about my amps, for what kind of purpose where they made ?
Does anybody have a
schematic?
What was the Sansui product
number?
Does anybody have the data
of the Sansui B705 output transformers?
Maybe these amps came from a
kind of Japanese Jukebox or church-organ? (These amps where intended for
use in a kind of console, because they did not have a bottom plate, I
had to manufacture an aluminum bottom plate by myself..)
The internal foil capacitors
where made by NTK, sadly I had to replace these Japanese caps, because
they caused a crackling noise due to micro shorts at 400 Volts
plate current... Maybe they
are not so durable as the old American ITT or Vitamin Q by Spraque foil
caps...
But its better to have these amps
running with American (vintage) caps, than keep them on a shelf totally
original just for view.
I had to invest around 300 hours to get these amps to "like new" condition, I removed all parts and sanded them before repaint with German
metallic quality car paint made for VW cars
and black Piano-paint on the transformers.
The oxidzed brass Sansui labels on the top
of the Transformers just needed a special treatment with a light acid
tincture for bathtubs cleaning and a soft re-polishing
with "never dull" chrome polish.
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