[sdiy] [AH] Buchla 192 design [was: Buchla used for Silver Apples of the Moon]

[cheater cheater]

ah right, ok makes sense. i wonder if you ever ended up trying that
hammond filter with another high pass filter, to see what happens?

can i just put any HPF in an op amp's feedback loop to get an lpf?

On Sat, Jun 26, 2010 at 21:40, Aaron Lanterman <lanterma at ece.gatech.edu> wrote:
>
> On Jun 26, 2010, at 3:35 PM, cheater cheater wrote:
>
>> Hmm, I remember there was something with a high pass in an op amp's
>> feedback, what was that again?
>
> Ah, yes, that was the Hammond 102200, which had a similar idea, except the four stages aren't buffered, and the Hammond uses FETs as variable resistors in its highpass core, which is placed in the feedback loop of an op amp to form a lowpass filter, whereas the Buchla stages are buffered, and they use diodes instead of FETs.
>
> It was a very touchy circuit.
>
> - Aaron