stereoplay 1988 Monoblock from Günter Mania

Hello Pytha2001,

i have built the Amp in 1996. I had the luck to get the original schematics from the first Monoblock they sold commercially.:)

It is different from the one which was in the stereoplay. I also built the stereoplay version but it didn't work.:(

In the original schematics there are 2 modules. One is the protection circuit, the other is for dynamic DC compensation.
You don't see the schematic it's only decribed as module (you see a black box in the scheme)

I took the DC thing from elektor, and the protection circuit i developed on my own. I was very proud on it, because it works without relay at the output, just the AVM philosophy.
Don't ask me for pics, i have no digi cam.

Since 1996 they work very well, and the protection circuit hat no reason to work until now.:)

Regards Markus

PS: I registered only to reply this thread. I haven't done anything with electronics the last years. When you've built a house, there are other things to work on. Sorry for my bad english


2004-03-12 8:42 am
Hallo Markus und Klaus

Although I would prefer to write in German, I don’t know if it is more appropriate to write in English in this forum? I’m a newbie...

I have stored this article since 15 years :D and, after getting a little more time again, would also like to start this project. But it doesn't seem that a lot of people have build this amp. I found only this:

@ Markus
Could you also send me the schematics of the “alternative” circuit? Is this circuit completely different? From what I knew, it should not have been that much different.
Ehm, what about your protection circuit? I know, it’s your own stuff.. :angel: ..can you explain something about that?
And, what kind of problems did you experience with the basic design? Did you use a DIY PCB, or a breadboard?

I tried to start a thread at

but with low success.
Perhaps here we will find some more people interested in a discussion?



2002-12-13 1:12 pm

I didn't build this amplifier but a similar self-designed at that time.
In stereoplay magazine, some readers complained about sharp hights at high levels but were happy about great bass control at all output levels. The amplifiers were said to be precise with a tendency to sharpness. Same with my amps....
The problems with the mosfets is that they very easily oscillate. In my amp very small gate resistors of 10 ohms (if I remember correctly) and a new layout stopped the oscillation.
In the AVM design, no explicit compensation capacitors are used. But in deed they are in, because the collector to base voltage of the input transistors is 0 Volt and so the collector to base capacitance is about 20pF (as I remember correctly).
In my opinion the amplifier I buid is good for techno or heavy metall and I expect the AVM to be the same.

Hallo Markus,

im deutschen bin ich auch eher zuhause. Kannst du mir das Schaltbild des AVM-Monoblocks zukommen lassen ??
by German language I am rather at home. Can you send me the schematic ??

Wäre prima ! That would be fine !

here are the diy instructions about webarchive:
Internet Archive Wayback Machine and jpg file about

I have found this advice and the old original, currently no longer existing URLs about the forum
go to post from BN from 14.11.2003, 18:42

about #73 from
you find a schematic version from me
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