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Re: Matched transistors in VCA (CGS64)

2007-06-07 by Dave Kendall

Hi Louis.

On 7 Jun 2007, at 11:58, Louis van Dompselaar wrote:

>
> > Would matching with the transistor tester in a DMM do the trick, or
> do
> > you need to measure parameters other than HFE?
>
> Transistors are usually matched on Vbe.
>
> That said, transistors /from the same batch/ that are close in Hfe are
> probably
> close in other specs as well. So yes, you might get away with
> checking Hfe.
>
> I did just that building the Yusynth Minimoog clone and it sounds
> great and
> even tracks well enough. That might also be plain good fortune though
> ;)
>
> Check this thread:
> http://electro-music.com/forum/viewtopic.php?highlight=matching&t=18365
>
> Louis
>
Thanks for the tip.
I checked this circuit
http://www.oldcrows.net/~patchell/matcher/matcher.html
It shows a PNP tranny.
Would NPNs also work?

Also (this may be a dumb question....) What does the D.U.T. refer to at
top right of the schemo? GND maybe? it isn't the
multimeter............

cheers,

Dave

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