Using the amp for HiFi purposes:
1. Install an RCA jack
The best way to use this amp is to ignore all those inputs
for projectors, photographic movie sound and microphones.
Solder an RCA
jack to point 5 and 4 (ground) of the short connection panel (as
shown on the picture left).
Now you only
use the last 2 EF12k tubes. They must be used both as the feedback
loop goes back to the third EF12k tube.
2. Connect the
speaker to point #1 and
the large panel
3. Connect a power
cord and play !!!
4. The sound:
you may notice a strong bass and slightly damped highs.
this amp does not have a modern hifi frequency response. The bass
response reminds on a loudness curve and the highs start getting down
at 2kHz. I have tested this on two amps (see pictures below), but
I'd never modify this !!!