SEM Style knobbies

[gstopp at fibermux.com]

     Ya know you can do this single pot thing (see Juergen's reply) with 
     the ASM-1. Just don't use the Notch output and run the LP and HP 
     outputs to a pot (this is one reason I didn't add 1K output resistors 
     on the filter outputs on the ASM-1). If you want you can try to find 
     the switch type (I think a SPDT would do) to do the BP thing as well. 
     And furthermore you could hack the now-unused Notch op-amp into a 
     buffer for the pot wiper to provide a low-inpedance output.
     
     - Gene 


______________________________ Reply Separator _________________________________
Subject: SEM Style knobbies
Author:  Christopher List <Christopher_List at sonymusic.com> at ccrelayout
Date:    6/5/96 6:21 AM


Hi List - 
     
A week ago "SEM style inputs" were discussed, and it was mentioned that the SEM 
filters have a knob to x-fade from HP through notch to lowpass.
     
I do this kind of thing now all time using a dedicated x-fader module and 
realize what a great idea it is to have it as part of the filter itself. 
     
I don't want to be able to voltage control this x-fade, so I don't want to do 
it with VCA's. It seems like it would be easy to do this x-fade with a 
dual-ganged pot, but I was wondering if there's an easy "trick" circuit for 
doing this using only a normal pot and op-amps. I'm not looking for "true" 
exponential x-fade, BTW.
     
- Thanks,
Chris