Moog Transistor Matcher Questions

[Romeo Fahl]

Thanks for the feedback, everyone.

Turns out the problem was that someone sold me 49 ohm resistors instead of
49.9k. I'm not very good at reading precision resistor codes which is why
the problem eluded me until this morning.  That'll teach me to go to Radar.

Romeo



----- Original Message -----
From: "Grant Richter" <grichter at asapnet.net>
To: <owner-synth-diy at node12b53.a2000.nl>; ">>>marjan<<<" <urekar.m at EUnet.yu>
Cc: "diy" <synth-diy at node12b53.a2000.nl>
Sent: Saturday, December 30, 2000 8:41 AM
Subject: Re: Moog Transistor Matcher Questions


> It's also difficult during winter because the furnace is cycling around a
5
> degree deadband. If you turn the furnace off, then you have (hopefully) a
> long temperature droop. At 2.2mv per degree C (or about 1mv per degree F)
> the room temperature needs to be stable for about 10 minutes to get a
group
> of transistors at the same temperature.
>
> So set your thermostat down before you start so the furnace doesn't kick
in
> while matching.
>
> > From: jhaible at t-online.de (jh.)
> > Reply-To: owner-synth-diy at node12b53.a2000.nl
> > Date: Sat, 30 Dec 2000 14:17:06 +0100
> > To: ">>>marjan<<<" <urekar.m at EUnet.yu>
> > Cc: "diy" <synth-diy at node12b53.a2000.nl>
> > Subject: Re: Moog Transistor Matcher Questions
> >
> >>> I've noticed that the measurements aren't steady at all. Once I turn
> > the
> >>> power on, the voltage reading on the voltmeter seems to drop as I
watch.
> >>
> >> :) This is very obvious illustration of all the talk about the need for
> >> temp compensation of expo pair. You see how it changes with
temperature.
> >> Try to do it in constant temp room, away from open air flow (window,
> >> doors).
> >> Also be sure to use tweezers to pick and install transistors you test
as
> >> heat from your fingers heats transistor a bit and you get some reading
> >> that
> >> quickly changes as heat is dropped. That's how sensitive it is...
> >
> > Very true. It's a pain.
> > Last time I matched transistors, I arranged them so that I only had to
touch
> > them with my fingers for a second or less, but I still had to wait more
> > than a minute or two for each transistor's measurement.
> >
> > I have an idea how I will do it next time, but I have not tried it yet:
> >
> > I'll stick a whole batch of transistors side by side into one of these
> > white, solderless prototype boards, and I'll make a cable with 3-pole
> > plug to contact the protoboard from the Vbe test circuit. Then the
> > procedure would be:
> >
> > Stick in 20 transitors at once, wait 2 minutes (or even 5) until they
> > are all settled, and then probe them with that special plug one by one,
> > (hopefully) without stirring their temperature.
> >
> > Anybody tried this ?
> >
> > JH.
> >
> >
>
>