Hi Ingo,

> Hello Tim, thank you very much for your efforts. Highly appreciated.

My pleasure!

> Thanks to your suggestion and my solder sucker I've swapped the B50K
> pot for a C50K in a fly. The result is much more to my liking.

Great, sounds like we're moving in the right direction!

> I still like to give your 2nd mod a try but I'm not sure wether I

get

> it.

OK, but...

> Even worse my A101-2 is a prototype thus there are no part numbers
> on the board.

...thus your module *might* be slightly different!

> Pls verify if I've understood how to proceed:
> I'm going to link the res. pots wiper (= 2nd pin i.e. the one in the
> middle)

<snip>

As you look at the pot from the front, simply short the middle pin to
the right-hand end - if your module *is* as the schematic I have,
this end should go to the 47k resistor, and pin 2 on the amplifier
chip (LM324), and a 100p cap. If the wiper is already connected to
this point, then it looks like it may have got changed for the
production version (it is a fairly subtle change after all!) - the
other end of the 47k should go to ground, and you *don't* want to
connect the wiper there! If you're still not sure, get back to me.

I'm just about finished writing up some slightly more detailed notes,
mostly for my own benefit, but I will send a copy to Dieter so that
he can see what I have done/am suggesting.

As I mentioned before it is possibly that this change will move the
whole resonance peak down to a lower pot setting - if this is
happening you should detect that the resonance *decreases* again as
the pot is rotated further clockwise from some given point. If you
think this is happening let me know, and I can probably make a
suggestion on how to cure it (basically replacing that 47k with a
slightly larger value).

Good luck,

Tim