Hey guys.
I know my way around a soldering iron & have a basic understanding of electronics, but I'm not an EE & I don't own a scope.
Still, I'm hoping I might be able to fix this problem myself, if you guys can point me to the most likely source:
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I have a True Systems Precision8 mic preamp. AFAIK, it's all discrete.
One channel (only) has suddenly started outputing a fairly high level of steady HF noise. Everything still works: The frequency response seems correct, the volume pot works as expected, etc.
The other 7 channels are dead silent.
(And no, it's not the wiring, etc.)
I don't have the schematic yet, but I'm searching.....
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Any ideas or suggestions?
I know my way around a soldering iron & have a basic understanding of electronics, but I'm not an EE & I don't own a scope.
Still, I'm hoping I might be able to fix this problem myself, if you guys can point me to the most likely source:
-------------------------
I have a True Systems Precision8 mic preamp. AFAIK, it's all discrete.
One channel (only) has suddenly started outputing a fairly high level of steady HF noise. Everything still works: The frequency response seems correct, the volume pot works as expected, etc.
The other 7 channels are dead silent.
(And no, it's not the wiring, etc.)
I don't have the schematic yet, but I'm searching.....
---------------------------------------
Any ideas or suggestions?
Without a schematic and a scope the best I can suggest is that you need to get someone to sit down with you in person and run it through a scope for you.
In the mean time you can look for shorts, water damage etc...
In the mean time you can look for shorts, water damage etc...
Does the volume control affect the volume of noise? That should provide a clue to the noisy component.
Good thought!
And no, it does not affect the volume of this residual noise at all.
I assume that means the noise is on the output path, yes?
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I'll be opening it up this weekend. Maybe I'll get lucky I find a bad resistor.
Or maybe this is a chip design after all, and I can try replacing the one op amp. - But if it were an op amp, the noise would likely follow the volume knob, no?
If it's discrete, maybe a bad output transistor?
Any of the above. Happy hunting. A signal tracer or oscilloscope will help, you can use another channel for comparison.
Another trick is heat/cold on the individual components, see where it makes a difference. Fingers work for heat. Cold usually freeze spray or an inverted compressed air can.
Another trick is heat/cold on the individual components, see where it makes a difference. Fingers work for heat. Cold usually freeze spray or an inverted compressed air can.