Moog Transistor Matcher Questions

RFAHL 8brain at spiritone.com
Sat Dec 30 08:49:29 CET 2000


I just finished making a copy of the moog transistor matcher.  I'm powering
it off +/-15 V, which according to the notes on the diagram is ok.

The circuit seems to be getting really hot.  I'm using a BA4558 and it is
too hot too touch when the circuit is on.  the regulators get really hot on
the power supply, even though only the matcher is being powered.  I checked
the circuit out and I've assembled it correctly as far as I can tell(I did
add the resistor that's missing in the moog diagram).  Can this circuit
really handle +/- 15 V?

 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.
I'm assuming that as the transistor heats up more current flows through it,
lowering the Vbe.  I would assume that the circuit would be stable and not
subject to much change.

Any ideas as to what the problem may be?

Romeo




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