> Hi Dieter and thank you for the reply.
>
> I can not be to certain to the accuracy of my monitoring of the
> sound - but, with the settings I mentioned above it is almost
> touching the -4dB level on my hardware mixer (with no extra gain)
> and roughly the same in my DAW.... so pretty loud!
>
> I should have recorded a sample with audio input for comparison,
> but with lower frequency input the sound is fairly noticeable as
> the LFO cycles... even more so with higher frequencies as the
> sound is fairly low.... it makes a useful kick drum btw! ;)
>
> I only had the filter for a short period before I sent for the
> replacement, but I am almost certain that it never behaved this
> way at first... it seems striking that the replacement would be the same.
>
> Having said that; I have eight filters in my system - five of
> them being Doepfer and this is definitely one of my favorites - a
> wonderful smooth sound and I personally prefer its more
> ''darker'' tone compared to its nearest rival.
>
>
> Best wishes

I took an A-105 module from stock and measured indeed a control voltage
feedthrough of about 30mVpp (i.e. if the CV changes the output voltage
changes up to 30mV without audio input). The full level of the module before
clipping is about 15Vpp. So the measured control voltage feedthrough is
25mV/15V = 0,017 which is -35dB. That's very close to the specified -36dB
control voltage feedthrough in the SSM2044 data sheet. So I suppose that
it's just the control voltage feedthrough which you hear. Maybe we should
add this information to the A-105 specs (which are in the end nothing but
the spec of the SSM2044). The output voltage follows not exactly the CV
input signal but is assymetrical (or distorted), i.e. modulating the filter
frequency e.g. with a sine wave does not generate a sine wave at the output
but a very distorted sine (like a waveshaper). If the CV input is in the
audio range you will hear the frequency of the modulation LFO at the A-105
output even without any input signal (about -35dB compared to the full 15V
signal with audio input).

Best wishes
Dieter Doepfer