Andrew,
Not to inconvenience Grant or anything, I thought that you might like
to know a modification that Grant did for my Omni Filter.
I remarked to Grant on how the Bandpass mode output was significantly
quieter than the other modes, and that, often, I needed more gain to
drive the filter, especially when using a single input (rather than a
mix of the 4 input).
He suggested a value change of the summing resistors would result in a
6db gain increase, which improved the filter's quite a bit.
I should also mention, that lowering the resistor's value has made the
input less bulletproof. I accidentally put a Borg filter into
oscillation while patched to the Filter's input and promptly blew out
the chip!
I suppose that the Borg's 27 volt p-p output when oscillating had
something to do with it.
So now, as a habit, I set my Omni Filter input pots to about 2
o'clock, so as not to invite disaster one more time
(I still love those Borgs with high resonance, though - speaking of
courting with disaster. They are not "constant Q", so a
non-oscillating Q setting at a lower frequency may possibly oscillate
when the Freq is set higher).
Gary