Small power amp hum.

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I have a small power amplifier that just developed a hum on the left
channel. Someone said it may be a capacitor. Since I do not have
anything to test the caps I wonder if there is a another way of
testing for component failure? Thanks...

Zap

[Paul Stamler]

> wrote in message
...
> I have a small power amplifier that just developed a hum on the left
> channel. Someone said it may be a capacitor. Since I do not have
> anything to test the caps I wonder if there is a another way of
> testing for component failure? Thanks...

It would help if we knew what power amp this was -- brand and model.
However, I'll hazard a guess that it isn't one of the main power supply
capacitors. The reason I suggest this is that in most small power amps, the
same power supply caps feed both channels, so if one of them went out it
would affect both channels. There may be a bad decoupling cap in one
channel, though, or a loose ground connection.

My suggestion is that you open the box and look for loose connections or
burned components. If you don't find any, take it in for repair; if you have
no test gear you're not likely to find much beyond the visually obvious.

Peace,
Paul

[Scott Dorsey]

> wrote:
>I have a small power amplifier that just developed a hum on the left
>channel. Someone said it may be a capacitor. Since I do not have
>anything to test the caps I wonder if there is a another way of
>testing for component failure? Thanks...

What do you have? Do you have a scope, a signal generator, and a dummy
load? Do you have a service manual?

Bad bypass caps are popular failure items. So are ground connections,
especially on amps with grounds to the case. But since you don't even
mention basic information like what model amplifier it is, it's hard to
really say anything.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."