[sdiy] discrete ota trimming

[Ryan Williams]

hi all,

I just got some samples from intersil of the HFA3096 3NPN, 2PNP array. I 
wanted to try some experiments for discrete OTAs in VCFs with these. the 
OTA circuit is basically like the one used in the JH ssm2040 filter. 
What I am unsure about is the best way to add a trimmer. Here's what I 
have now that works in simulations ok:

http://www.sdiy.org/destrukto/schematics/discrete_ota.gif

so, is that a bad way to do it? should I put the trimmer on one of the 
Vin pins instead like what is normally done in CA3080 type circuits? I 
deffinently want to be able to trim the offset. this is going to be for 
a state variable filter.

thanks--Ryan