More on moog filter band pass mode.

[BJ]

> Hot off the simulation... Band pass over audible range is -6dB/oct each
> side of centre frequency. Equal amounts from top and bottom differential
> amplifiers are subtracted. Use 1% resistors to summing amp, or a trimmer
> pot to make sure both sides subtract ok. Odd that it should be
> equivalent to 2-pole SVF. However, it sounds great.
> 
> Regards,
> 
> Tony Allgood, Cumbria, UK

Hmm, interesting, now if you conect the lower buffer and diff amp
to the nexst 6db filter pole,at the 12db transistor/capp diff pair
so to speak ,then you get a 12db HP in a mix with the 24db lopass
makes a 24db BP? or what?

Strange, usually a HP and a LP in a mix makes a Notch response!

Hmm,it must depend on that the lower 6db transistor/cap pair
are lower in frequency than the 24 db transistor/cap pair pair is!!

Hmm again,if you do as i mention 2stepps abowe then the 12db BP filter
would have a narrower bandwith then the 12db BP!!!

Have any one at diy tried to add another 6db pole to get a 30db filter?
If so,how much more noise did you get?

JB