Dirty voltage PC Power Supply

[kasumyku]

Hello everyone,

I just got a brand new PC power supply and I have a little problem with it.

First of all I'm using it to power up a car amplifier, the issue is that there is a constant humming noise coming from the subwoofer and the only way to eliminate this is by using a car battery, so the problem is not the amplifier...

Can anyone please tell me how can I get rid of the humming noise, does removing ground prong would make any difference or is there any modifications that can be done to the power supply?

p.s.: worse comes to worst I'll be end up using it as a bench power supply, but for now I would really like to know what makes this humming noise ...

Thank you!!

[uncle_bob]

Hi

Your PC power supply may (or may not) have some problems:

1) It may require a certain minimum load on certain outputs to regulate in a quiet fashion.

2) It may be broken and be noisy as a result

3) It may just plain be noisy all the time on the +12 even when working correctly

4) It might be overloaded (this is unlikely).

If you want to try something, get a few 4,700 uF 16 V caps and start throwing them on the 12V supply lead. If you get past 10 caps and still have the problem. Get another supply. PC supplies are not designed for low noise audio work. If you go shopping for something else, get a supply designed for audio.

Bob

[Seekonk]

Not a fan of these conversions, you accept what is printed on the label is real.  This supply can only regulate one output voltage, the +5V.  The other one just tags along. Putting a couple amp load on the 5V would make it run better.  It was never designed to function like you want.

[daveshah]

Is the amplifier connected to a grounded signal source (i.e. a desktop PC) when this happens? If so, the proper way to deal with the noise is not removing ground from one of the devices (which may work, but presents a safety hazard), but using a differential input to the amplifier (either a passive transformer or active opamp circuit).

[Kevman]

Try it with a battery powered device first, like a phone, and see if the humming goes away.