Preventing ground loops - Head unit/Audio Processor grounds
 

Hey all,

Just wondering if your head unit (and eq/processor where applicable) should be grounded to the same location of your amp.

Obviously in most set ups that would mean a long-ass wire to the back of your car from your console. I just have a hissing noise present ever since installing my Pioneer DEQ-9200. RCA's are away from power wire, grounds are clean, big 3 done but still the noise.


Thanks folks.

Not usually necessary.

Hiss usually means your amp gains are too high.

I suggest finding the source of your hiss. Use an mp3 player (or anything with a headphone jack) then get a 3.5mm (headphone jack) to RCA and use your mp3 player as the audio source. Is there still a hiss? Then its the amp, if not, its your deck.

The gains [on your amp] too high suggestion from DuKK is probably right.

Ill definitely do as you say - it's so clearly how I should have answered my question.

Here's the deal though, the hiss started when I added a 500mV output sound processor into my system. The Alpine DEQ9200, if any of you know it. Obviously that points to amp gains but the gains are only at about 50%. They can go to nearly 100% without clipping but I just dont need that kind of volume for day to day.

It's not about where the gains are on the dial but more that they are properly set to match the system.

Did you ever get this solved?

Nope. The audio processor is just noisy as hell. What's odd is that the hiss increases with audio processor volume but not head unit volume. Which means the hiss is not proportional to overall signal, just % of max processor volume. I guess that means the noise is created somewhere inside the processor. The 500mV outputs of the processor cause the gains on my amp to be set pretty high which I'm sure doesn't help either.