[sdiy] THAT 2180 as current switch

[mark verbos]

Chad,

I don't see any reason that you couldn't get that to work. One thing to 
think about is whether  they invert the signal that goes through them. I 
think you could add the integrator after it and the comparator after 
that and feed back to the VCA and have a triangle oscillator. I would 
just flat out steal those other parts from Don.

The upside is you eliminate a whole bunch of parts. The downside is that 
you lose the linear FM. You could use 2 sections of the SSM2164 and do a 
feedback arrangement like Mike Irwinn's VCA to get a linear in as well. 
Be careful with the CV gain. Obviously the exponential in has to be 
trimmed to volt/octave (or 2 volts per octave if you really wanna 
emulate a 259!) but be careful with the linear FM gain, since this is a 
part of Buchla's oscillator sound.


Good luck!

Mark



Chad Cosby wrote:
> I'm trying to make the make Buchla's triangle-core oscillator using a 
> amp w/ exponential gain control (THAT 2180 or SSM2164) as the 
> exponential converter and the current switch.   Does any one know if I 
> can get one of these guys to behave like Buchla's voltage starved OTA?
> 
> Chad
> 
>