Hi again,
looks like everything got solved. It certainly looks like I'm asking too
much On other speakers ( 90 db) the Alpha 3 works not too bad. My
speakers offer only about 86 db (1W/1m). Right now, all of the important
electronic parts have been replaced - works fine now. Although I would have
been pleased with a little bit more power. BUT, the sound is very "british"
(like it), warm and "analog". Many thx again to all, many thx for all your
input.

Best rgds
Uwe
"Tim Schwartz" schrieb im Newsbeitrag
...
Uwe,

Have you measured the output power into 8 ohm loads? This will tell you
if there is any fault in the amp. As I said earlier, this is a low power
amp, and you might be asking too much of it. If it is delivering rated
power at clipping, you need to expect less volume or get a more powerful
amp.

Regards,
Tim Schwartz
Bristol Electronics

Uwe Surojegin wrote:

Hi John, Hi all,
many thanks for all your input. Specially to John from Arcam who faxed
me
the circuit diagram!!! If this amp is not going to work any more ... I
probably consider another ARCAM because of the excellent support !!!
First of all: The 12 o'clock clipping would not worry me if the output
would
be adequate at 11. It's somehow not very loud.
FYI: I replaced the 50K Ohm volume potentiometer with an 20K Ohm. No
improvement. The CD player output I checked again: Its acutally close to
2,5
V !!! So that could be a reason. I double-checked with a scope and a
50Hz
squared input signal, 3V. Going close to 12 ... the reading at the CD
chinch input ! already showed clipping with the scope !!! Strange!!! And
actually all the way through the amp section. Next steps I will do is
checking on the capacitors etc. If this aint gonna help ... - bonfire

I'll keep you posted.

Uwe

"Uwe Surojegin" schrieb im Newsbeitrag
...
Hi Norbert,
I connected already a 33K Ohm resistor parallel to the poti. I'll keep
you
posted ... next steps are with oszilloscope to check the AC and DC
voltage
from the transformer and so on....

Uwe


"Norbert Hahn" schrieb im Newsbeitrag
...
"Uwe Surojegin" wrote:

I checked my CD player output: Very low voltage, not nearly close
to
300
mV.

Only a very few CD players have such low output voltage, unless they
have a volume control.

Of course, I had to replace the volume poti (was broken, originally
I
guess
20K Ohm) and replaced it with a 50K Ohm Alps potentiometer. So this
could
certainly not be the case.

The volume control of my amp is located in the feed back loop, thus
its value is important. Replacing a 20 kOhm potentiometer with a
50 kOhm type would influence stability.

But I don't know your amp so it can be a different problem. OTOH you
may
simple connect a resistor in parallel to the volume pot (47 kOhm are
a
good start) and check if the distortion/oscillations are gone.

HTH
Norbert