[sdiy] Moog Filtered Ale anyone?

[Aaron Lanterman]

On May 5, 2010, at 4:57 PM, Dave Manley wrote:

> Not likely, unless it was Harry's ladder with inductors.
> 
> For beer you need a high pass filter.

Incidentally, one of my students built the Moog highpass filter (with capacitors) - video coming soon.

The ladder is quite different, though, the control current doesn't run through the whole ladder cascade (I guess it's cascode, really?) as in the lowpass; each section is separate.

We wound up taking out the resonance path - dialing in the *slightest* bit of resonance caused ultrasonic screaming the likes of which I have never seen, and I didn't feel like trying to fix it. I seem to recall someone mentioning that the real Moog 904B didn't have a resonance path (although there is one on the patent IIRC).

- Aaron