Doepfer

hi Markus

> Hi, I'm new to the group and have set my A100 to operation for the first 
> time a few days ago. I have one question concerning the high end 
> VCO A-111. When I modulate the PCV-Input with an LFO and turn the 
> PCV knob clockwise, there is also a weak FM in all signal outputs, 
> bad enough not to use PWM.
Pay attention: the faster the PWM, the more it will sound like pitch 
modulation. For our ear a width modulated pulsewave is not one up and 
one down movement but two peaks, where one is frequency modulated[*]. If 
the FM seems to get weaker with slower LFO frequencies, then your A-111 
is not buggy but you discovered a nice psychoacoustical phenomenon.

As rule of thumb you can say: the faster the modulating frequency is, 
the smaller the modulation amount should be


Florian

[*] you can test this by sending a pulswave through a unmodulatied 
phaseshifter and listening only to the effectsignal and then listen only 
to the original signal (no mix) you won't hear a difference.
If you have a look at an oscilloscope (or wave edit window of a digitla 
recording tool), you will see that the waveforms look completely different.