Doepfer

I've noticed a few things with my A-121 Multimode Filter. I hope
someone can clarify, wether this is normal behaviour or not. (I think
I already posted the first issue once, but unfortunately I never got a
reply...)

1. In direct comparison with the A-105 SSM Filter, the output level is
about 20 dB lower. I set the input levels of both filters to a level,
where the signal is at the maximum level without any distortion (which
is about half way up on the A-105 and somewhere slightly below the
maximum input level on the A-121)

2. At low(est) fc settings, the highpass sounds like it is filtering
high frequency(!) components from the signal. I don't assume, that
this is normal behaviour, or is it?
Furthermore: With fc at maximum, I still hear the signal. Is there a
way to increase the range, so that at the highest fc setting, the
signal is inaudible?

3. The notch-filter seems to behave simliarly to the highpass, in that
it seems to filter high frequencies, when fc is set low.

Are these three points common problems, that are explained in the way
the module is built, or is my A-121 simply defective?

I'd be grateful for any clarifying reply.
Thanks,
-Michael