[sdiy] 2n3904 transistor matching stats

[Tom Wiltshire]

Ian Fritz' method is the best:

http://ijfritz.byethost4.com/MiscProj/transmat001.pdf

Lots of people use the Moog matcher schematic which is floating around the web, but Ian's is better, for reasons explained in the document.

On 8 Jun 2016, at 12:51, Logan Mitchell Sr <prowlerraven32 at hotmail.com> wrote:

> What is the method of performing the matching checks using an analog or digital meter & what readings should I look for on each one since I have some 2N3904's & 2N3906's.
> 
> Logan
> 
> > From: Matthias.Herrmann at jeppesen.com
> > To: davebr at modularsynthesis.com; synth-diy at dropmix.xs4all.nl
> > Date: Wed, 8 Jun 2016 09:18:26 +0200
> > Subject: Re: [sdiy] 2n3904 transistor matching stats
> > 
> > That's exactly what I experienced over the last years, however, I did no statistics.
> > So thank you for verifying.
> > 
> > Cheers,
> > Matthias
> > 
> > > From: Synth-diy [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of
> > > Dave Brown
> > > Sent: Wednesday, June 08, 2016 7:43 AM
> > > To: 'synthdiy diy' <synth-diy at dropmix.xs4all.nl>
> > > Subject: Re: [sdiy] 2n3904 transistor matching stats
> > > 
> > > I just built a design for a customer that needed 6 matched pair of 2N3906s.  I
> > > bought them on cut tape and verified matching with my 577 curve tracer.  I
> > > was literally unable to tell any difference between adjacent pairs.  Then I
> > > tested the 1st on the cut tape against the 12th and I could detect a very
> > > minor difference.  I was impressed.
> > > 
> > > Then I tested a random batch of loose transistors of another type.  There
> > > were more significant differences but it seemed like a Gaussian distribution
> > > with many close in characteristics and a few outliers.  It was much tighter
> > > than I expected, but for all I know they came out of the same batch as they
> > > were not a high volume runner.
> > > 
> > > Dave
> > > 
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