Hi Florian,

> There is a modification that gives a much better highpass behaviour

at low

> cutoff frequencies to the A-121. I don't know whether it is

documented in

> the service manual. But this may cause a uncontrolled and unwanted self
> oscillation in high cutoff frequencies.

Thanks, that's interesting to know. The service manual potentially
contains much useful info, but the price rather puts me off!!

> > I don't have an A-123 high pass module, but I
> > note that it uses the same CEM 3320 chip - it would be interesting to
> > hear from other list members whether it behaves in a similar fashion.
> No. As far I understood the problem appears only in the state-variable
> circuit. And the 123 is a pute pure hipass filter.

This is also nice to know, thanks again!

Tim

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