(click photo to download schematic pdf - ~120kB)
I always wanted to do a small triode push pull amp.
Small means always tubes with two systems in one envelope.
Because the European Manufacturers decided to put only small
signal triode/power pentode combinations (ECL - Family) in
one tube I had to look for US types.
They put triode/power triode systems in one tube.
After a short inquiry on the web, I found the 6em7/6ea7 tube.
This tube was integrated in almost every past made US TV.
Out of this reason this tube is reasonably easy to get in NOS/NIB versions today.
But due to the high demand in the US itself and from
Asia, esp. Japan and Taiwan it's getting costlier and costlier.
So it's remarkable only for laymen that the schematic that I found came from Japan.
I didn't understand a word written at the japanese web site,
but I found the original schematic by accident.
Unfortunately all the original links are broken in the meantime (Oct/04/2009).
The schematic was simple enough to fulfil the KISS principle, and because I heard
various enthusiasm about the 6em7 sound, I decided to give this amp a try.
The parts are from my desk (output trannies from a cannibalized K+H Telewatt VS56),
from an ebay auction (trannie), from a neon bulb (choke), from TubeWorld (tubes),
from a Flea Market (the cabinet is an old NEXTstation) and from Reichelt ("normal" devices).
I build this amp and it ran at first go.
It's a wonderful amp, which is putting out 2x 8 Watts in a superb quality,
even with non superb components (see above).
I can assure you that this amp has a superb price/performance ratio,
esp. if you have the fitting output trannies somewhere
in the depth of your tinker's universe.
As always: Feel free to contact me if you have any questions, comments, suggestions etc.
The Web Site addresses from the mentioned suppliers can be found at the audio/diy-linkZ section.
©
by
valviac 20xx