[sdiy] Semi-OT: bass-amp problem

[Tony Allgood]

>On powering up it works fine, but after a while the volume decreases
until you can't hear anything. Then suddenly, without warning, it bursts
into full volume again

This may or not be: the temperature sensor(s) on the power amp's
heatsink. If you're overheating, one may shut the audio path way to the
power amp. Its usually a thermistor of some sort that shunts the audio
to ground. It may also have another thermal cut-out that acts on the
output of the amp. The former is normally slowish to act, but the latter
is very fast. You may have a combination of both.

If it is this problem then it may be a duff bias (quiscent current)
trimmer.

Regards,

Tony Allgood, Penrith, Cumbria, England

Oakley Modular Synth and TB3030:
www.oakleysound.com/projects.htm
My music: www.mp3.com/taklamakan