[sdiy] Modern transistor matching

JH. jhaible at debitel.net
Mon Mar 31 23:09:26 CEST 2008

I noticed the 2SC945s and 2SA733s I used for the PolyKorg Clone were rather 
well-matched out of the bag as well.
(And I didn't need pairs, I needed 49 ones matched to 2mV !)
My "standard" parts BC550C and BC560C have been much worse.
But then again, I didn't do any matching for a few years, with LM394s so 
cheap ...


Now playing: David Sylvian, Gone To Earth

----- Original Message ----- 
From: "Tim Daugard" <daugard at sprintmail.com>
To: "Grant Richter" <grichter at asapnet.net>; "Bruce Duncan" 
<modcan at sympatico.ca>
Cc: "synth-diy" <synth-diy at dropmix.xs4all.nl>
Sent: Friday, March 21, 2008 4:31 PM
Subject: Re: [sdiy] Modern transistor matching

From: "Grant Richter" <grichter at asapnet.net>
> The last bag of 100 x 2N3904 transistors I got from Mouser, I sorted
> them by my usual method.
> All 100 tested +/- 1 mv. of each other at room temperature (all 100
> came out of bag matched to each other to Moog spec.)

I noticed the same thing the last time I tried to match transistors. I 
thought I was doing
something wrong. I went on and matched the transistors for gain (Hfe on my 
meter). I found
enough transistors that matched (with my finger heated method) that I have 
groups of two's
and four's that are matched for Hfe within the limits of my meter. This 
sorting resulted
in fall outs on either end of high gain and low gain transistors which went 
into my bins
for special purposes. The transistors are used when I need extremes of high 
and low gain.

Mine are from Mouser also.

Tim Daugard
AG4GZ 30.4078N 86.6227W Alt: 12 feet above MSL
http://home.earthlink.net/~synthfred/h_toctop.htm (Fred's online edition)

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