> hi, friends
> I d like to boost a bit the input of my A121 filter, because i
> find it too low.., i read something about a120 mod but what about a121
>
> Thanks a lot , and best wishes from Spain!
> Miguel

Should be possible by reducing the value of R1 (220k) e.g. to 100k or 47k.
R1 is located just behind the topmost potentiometer. I cannot try it out
here as the A-121 is no longer available since about 6 years. But I think it
should work.

Best wishes
Dieter Doepfer