moog hp

[jh]

>You know what??? huh huh?? If you add (10) 10K
>resistors, one each from the output of each amp to 
>the non-inv input of the next. Put them in all the fb
>loops (changing the last amp to a lag circuit) then 
>connect one to the input side out of the first resistor 
>and one to the output side of the last then mix the 
>signals together you get a all-pass filter (phase shifter). 

You just re-invented the HiFli Phaser. (Diodes there, instead
of transistors, of course. See previous mail.)

>I just tried it cool!...humm I wonder if this means 
>removing the resistors from a phaser would make it a 
>hi-pass....

If you have that filter topology in a particular phaser, sure.

Just as you can switch a certain other phaser topology 
to LPF by grounding the capacitors.

Just beware of the resonance loop when you make these
changes. Especially a LPF convertet to a phaser tends
to "scream" in a not very pleasant way.

JH.