David_Dymaxion

My stereo has a constant, pretty loud, hiss. The former owner tried two different aftermarket stereos, he said both hissed like this. He said the original unit did not. The hiss seems to be constant, doesn't change pitch with engine rpm.

Any quick and dirty fixes? Is it true the stock unit is less likely to hiss? If so I may switch to that.

Thanks for any advice.

DJCobol

Check the ground wire. Either that, or the speakers and the head unit dont like eachother. The impedence ratings on both may be different.

David_Dymaxion

Good suggestions, thanks.

LS1 RULZ

Are you using an amp with this setup? If you are, the gain may be set too high causing the noise.

BROKKANIC

Radio Shack sells cheap noise filters that will get rid of that hiss

David_Dymaxion

That sounds like the easiest solution, thanks.

bman555

Could the head unit be sending too powerful a signal to the speakers? Or the signal is not strong enough and turning up the volume makes noise.

See if you can adjust the output on the headunit and see if that effects the noise.

NineSevenWS6

Yeah. We have a converter at work that will allow you to lower the radios voltage going into the amp; honestly cant remeber the name or PN off the top of my head.

I take it you have a Bose system?

David_Dymaxion

No Bose hiss. It hisses on two different aftermarket stereos. No separate amp. What is the impedence on the stock speakers? I thought impedence mismatch was a good theory.

So if it is reasonably quick and dirty to fix this one I will, otherwise I'll get a stock Bose or maybe an MP3 unit (although I'd hate to do that and have it hiss!).

NineSevenWS6

It is the bose tho?

CeeBee94Z

Yea I would definitely say that the hiss is coming from a bad ground somewhere or you are tying too many things to the same ground. Another common problem that a lot of people don't realize is that if the RCA cables and the power cables are run near or ontop of each other this can produce a lot of noise...so my suggestion is to hook it up right, but it may take some time to trace where it is coming from....or you could always go with a noise filter for a quick fix....hope this helps

David_Dymaxion

Thanks for the tips. Sorry I was not clear before, the original Bose unit did not hiss, but two subsequent aftermarket units both hiss. The hiss is constant, even if the volume is turned to zero.

NineSevenWS6

Yeah, might need that adapter then. Tone the aftermarket deck down a little.

BROKKANIC

So didn't try the filter?