[sdiy] LM394 vs. MAT02 vs. ?

[Metrophage]

--- Glen <mclilith at charter.net> wrote:

> At 11:24 AM 11/5/04 , Roy J. Tellason wrote: 
> >> The ARP VCOs I have seen (and heard) used a weird PNP/NPN pair.
> >Yeah,  they used either 2N3904/2N3906 or TZ81/TZ581.

> I didn't know that 2N3904/2N3906 was an odd match. Aren't those parts
> used together all the time?
> 
> thanks,
> Glen

In the same circuit, yes, of course. But in an expo converter for a
VCO? I usually see matched NPNs used for sawtooth VCOs, and PNPs used
for triangle VCOs. A "pair" consisting of one NPN plus one PNP is what
is weird, at least, I don't know of other VCOs which use converters
like this. I wonder whether or not it really is all that "exponential"!
The ARP VCOs are rumored to be quite stable, but I'd have to wonder
about the scale and tracking.

CJ


		
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