I have enjoyed my amp and head unit for a few years now but all of a sudden there is a horrendous buzz or hum when you turn it on. It is ok when the volume is turned to zero but as soon as you turn it up to even 1 it makes this awful noise.
I have isolated the problem to the rca input jacks going between the headset and the amp. When I unplug and plug in these jacks at the amp, there is a loud buzzing noise and it makes the subwoofer move. I have checked the jack wiring and all seems ok, no breaks etc.
Let me guess, pioneer HU... they have a very poor quality rca ground that often fails. It can be fixed by grounding the outer ring of the rca jacks to metal on the HU.
Hey guys, finally got around to trying the fix and it didn't work. However if I turn up the volume high enough I can hear the music. I have used a new RCA set and still no success. I don't think the amp is the problem. I can't see any broken speaker wires although I don't think that would cause this buzz. Any other ideas? Don
Have you guys seen this? http://bcae1.com/images/rca/temporaryrcashieldrepair.html It seems a bit complicated but, should I try to do this? I don't have a voltmeter??
That link describes the same procedure that is shown in the pic MS linked.
Again, you're just grounding the RCA jacks to the head unit ground (cage). The second option of fixing the trace on the board itself does the exact same thing; it's just more cosmetically attractive. Also, fixing the trace on the board is a pain since you basically have to take the entire head unit apart to pull the board out of the chassis.
What Pioneer head unit is it? I might be willing to buy it from you.
After you've done that rca ground fix, try grounding the HU to metal instead of using the ground wire in the factory harness. That will eliminate a ground loop if you have one. Noise in the rca signal is almost always a blown rca ground or a ground loop.
Thanks for the additional tips. I will try again with the rca ground and then HU to metal. So "fixing the trace on the board"; is that just soldering that pico fuse that they describe? Is that simple other than taking the HU apart?
Jexx, it is a DEH P-2500 XM ready about 5 years old. I have been very happy with it to date - great sound. I have it connected to a Soundstream Tarantula amp with a Kicker Sub and Infinity Kappa speakers. Cheers, Don
"fixing the trace on the board" was somewhat vague on my part, admittedly.
And yes, it is just soldering the pico fuse described. The new one needs to be the same type/rating as Perry Babin mentioned in that article.
It's a fairly straightforward repair, though the fuse might be hard to access (aka it's tiny or surrounded by other components). I think in the end, if you're decent at taking things apart and can solder fairly well, it's doable. But if the external grounding method doesn't work, then the whole process doesn't matter as that isn't the problem.
M.S. brings up a good point of getting a better ground to the head unit to solve the problem. Let us know if that works. If not, then back to the drawing board :P
Well, the external grounding didn't work so I am perplexed. Could a damaged speaker wire make such a horrendous noise?
FYI, when this first happened the noise was very loud even on volume level 1 and actually stayed the same as you increased the volume. I turned down/off a number of controls on the amp (HPF, LPH, Gain etc.) and that muted the noise. At some amp settings, when I turn the volume up on the HU, I actually start getting the music and it overrides the buzz for the most part but once you turn the volume down to normal listening range, the buzz dominates.
Could it be anything do do with my XM tuner or adapter which are accessories I purchased to get the xm radio thru the xm ready HU?
If one of the speaker wires somewhere along the way came into contact with metal and grounded itself out, that could and would lead to distortion in the speaker(s).
Have you done what I said about the ground? The HU ground wire, not the rcas. Cut the ground wire before it goes into the factory harness, extend the wire to somewhere metal, put a spade terminal on it, drive a zip-screw into the metal.
I have tried the ground as suggested but no difference but, I think I may have left the original ground still connected. If I did that might make I will check and try it again.
What next. I have two older HU's. The original one from my 2001 dodge truck with no input jacks and one from a 1998 Honda accord with jacks but different harness etc. Should I try hooking up one of those to see if the buzz goes away? That could mean a lot of rewiring etc.
Another thought. Before this became a chronic problem, on occasion over the last 6 months, I would get a bit of a buzz interference (similar but not as extreme) that would come and go. It would last a minute or two or a few hours then go away. Sometimes it seemed that it would come and go with sharp vehicle movements, corners etc. A few times I would check the rca's on my amp and push them in tight and whether by design or luck, the buzz would stop. That is not the case with the current buzz and I have checked the input/output plugs for integrity and that is not the problem.
However, could it be one of the other rca's connecting channels on the amp? Can they lose connectivity over time or could the jacks be a problem.
I have installed a different HU and there is no problem with loud buzz. Accordingly the problem is not the amp or the rca plugs. It is the HU. I have done everything to ground it. Do I now open up the HU and solder the pico fuse or is that not the problem if the ground didn't work? What next?
