[Jr.]

Hey all, it's been awhile.

I'm slowly replacing my entire Monsoon system in my 2005.5 wagon. I have a JVC KW-R500 HU, Kenwood tweeters and woofers in the front, Infinity References in the back, stock rear tweeters, and a Rockford R2 sub with its own amp. I recently bought a Dual XPE4700 (yes, not the best, I know) amp to replace the Monsoon, and I'm having problems figuring out where these noises are coming from.

Based on some research I'm assuming the hiss I hear with the Dual is caused by a grounding loop (it doesn't change with volume, and it's there with the engine off), and the variable whine I hear when the car is on is alternator hiss. I think this has to do with the way I grounded the Dual--right now, the way it's hooked up is that the +12v and remote wires are piggybacked from my sub amp (no problems with wiring here, so I'm using it as a reference), and the ground isn't really anywhere. I tried a few different places to put the grounding wire--sharing a bolt to the chassis with the ground wire from the sub amp; a few inches away from the same place; under the spare tire; on the other side of the car where the other taillight connects. I hear that hiss everywhere I've tried. Where else could I ground it? Should I just bring in another wire to go all the way back to the battery - spot, or is that still going to cause problems?

Thanks for any advice. I know my system is a hodgepodge of random stuff, but it actually does sound really good when you ignore the hiss.

 

[JayTheSnork]

I had a ground problem early on when I installed my system (Kenwood h/u, JL Audio amps, BA component speakers, and an Alpine R sub). my amps are located under the rear shelf; when I had originally grounded the amp, I thought I had a good one, but nope.

have you tried drilling a hole for the grounding bolt, grinding away the paint so there is just bare metal, and using a star washer under the bolt? that solved my problem. also, make sure the ground wire is less than 12" long - the shorter the better.

 

[soundguybob]

The hiss that you hear when the engine is off is most likely an issue with the gain stages on your amps, or simply a noisy output stage on that cheap HU. The alternator whine is a grounding issue.

 

[Jr.]

I'll try that, Jay. I tried using one of the holes that was left after I'd taken out that big black plastic thing the amp/CD changer was sitting on, but that didn't stop it. I'll try to drill out a hole somewhere on a different bit of metal and see what happens.

And yeah, I haven't really touched the gain on the amp except for setting it at about 3/4 max, so I need to check that out too. I just popped it in last night, so I haven't had a chance to do too much with it. I'm so glad I have a place to go from here now!

 

[JayTheSnork]

3/4 max gain might be a little much. frankly, I run the gains on my JL Audio amps at somewhere between 1/4 and 1/3, believe it or not.

 

[Jr.]

That explains why I usually listen to music at a volume of 3... :lol:. Currently de-idioting myself on mobile electronics, boy this is a process.

 

[Jr.]

Success! I ended up cutting about a foot off the grounding wire and swapped where the ground for the sub amp was and where the regular amp wire was, then I turned the gain way down. Sounds great. Both of you guys, thanks!