Descret OTA was "that Japanese site"

[Rene Schmitz]

At 01:00 23.02.99 -0500, you wrote:
>> From what I know this is the gm stage of the famous SSM2044.
>
>I have seen it before. I know I have but I don't remember what it was
>called. I went through my books and can't find it. Somebody help...it
>is hurting my head.

And of course my cortical memory had an error: I meant SSM2040.
See Juergen Haibles discrete 2040-clone. Its this circuit.
Or the innards of many opamps have this circuit (the mirror is then
replaced by a fixed current sink). Its omnipresent! 

>> Perhaps one could build this circuit with SMDs on a tiny PCB to plug them
>> into a 8 pin DIP to replace the CA3080 in existing circuits.
>
>Seems like a lot of work...unless of course it worked better than 3080s. I
>just thought it might be a better vca....only kidding about not needing
>600/700s.

Making a module would make some sense to me, it seems that you probably
could swap them for a 3080 in a 4-pole filter to make the sound more
2040-ish. I'd like to try it. Might not work always but in circuits with
darlington buffers it might 
emulate the sound. I doubt that it will work better, I think the extra
current mirrors of the 3080 (and LM13x00) allow the output to source
current from +Vcc and sink current to -Vcc. Whereas this circuit cannot
swing all the way to -Vcc.
This might cause a nonsymmetrical distortion, that could have its benefits in 
filters.

>I tried a few more things with it....whatever "it" is it's fun to play
>with.
>-tg
With a tiny module playing arround will be easier, just swap it in for a 3080.

Bye
 Rene



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