Contour Enthusiasts Group Archives Forums Modifications Audio Help; trouble with amp install

I installed a Pioneer HU with front, rear and SW preouts, and ran the stock speakers from the built in amp an bypassed the stock amp. The HU improved the sound and had no problems. Then I added some new front speakers, better sound and no problems. I then pulled the factory amp and intalled a 2x100 amp in it's place to run the front speakers, even better sound and no problems. I ran a 10G from the battery. I was able to purchase a 4x100 cheap so I figured I would use it to run the 4 door speakers and the 2x100 to run a sub in the future. I was advised if I was going to run 2 seperate amps I would need to run a 4G and 8 or 10G to the amps. I upgraded to a 4G power lead and split the power to a 9G to the amps behind the dash. I installed the 4x100 under the seat and grounded it to the seat track. The sub amp is connected but nothing is attached to it.

The problem is that when the HU is turned down to 00 there is an audible hum, as soon as the volume it turned to 01 the hum goes away. This would not be too bad, but the hum is present when switching between EQ settings or when changing radio stations. The hum wasn't there before so I must of done something wrong, but I don't know what? When the volume is turned up the sound is great and clear with no hum. I played with the gain in it's maximum and minimum settings but that doesn't affect the hum.

Can anyone help me

Sorry for the long post but wanted to give as much info as possible.

Not A Big Deal Really... You Just Need To Find A Better Ground. Also Make Sure That Your Battery Power And Amp Remotes Are Run On One Side Of The Car And Your Speaker Wires And RCA's Are Run Down The Opposite Side If At All Possible. Cheap Speaker Wire And RCA's Pick Up Audible Noise From The Power Wires.

If You Can't Run Them Down Opposite Sides, At Least Put As Much Distance Between Them As You Can. I Also Wouldn't Mount Your Amps Under The Dash For Cooling Reasons.
Kum Pai!!!!

Thanks PaleHorse, I will check my ground, I may not have removed enough paint from the seat track, I may just try and find another ground location, I just thought I would be better off witht he shortest ground wire possible. I think I used pretty good wire but the remote wire seemed rather flimsy, and I didn't seperate it at all from the speaker and RCA wires; I put the remote wire in the same wire loom with the speaker and RCA! I ran the wires under the center console so I will pull that up and seperate the power wire and remote wire as much as possible from the other wires as best I can. But I only get the hum when the volume is set to 00 or changing EQ settings or between radio stations. It seems as if the hum only comes up when there is no signal at all comming from the HU, otherwise it is crystal clear as soon as the volume is turned to 01. Also no engine whine etc.

The amp under the dash is a Blaupunkt PA2100 low heat, doesn't even get warm to the touch, was told one of the few amps suitable for placement in tight confines. But I will have to wait to make changes as it is supposed to snow today UGH and I don't have a garage anymore.

If your mounting under the seat, use one of the bolts that holds the seat to the floor.. put a ring terminal on the ground wire, remove some paint and wah la!

That is what I did, I Scraped away some paint on the track and used a ring terminal. The bolt is painted so I will scrape away the paint on the backside of the bolt and see if that helps. I was wondering if I should make a common ground?

You Know, I Was Thinking...You May Also Have Gotten A Bad Set Of RCA's Or (Hopefully Not) Have A Bad RCA Output From The Head Unit. Open The Dash Back Up And Wiggle All Of Your RCA Connections...Both HU Side Amp Side With The Volume Down And See If You Can "Trace" The Noise. Obviously Only If The Ground Thing Doesn't Work For You. Lemme Know!!

yeah i had same problem turned out to be bad grounding then a bad altenator and rcas picking up noise so i ran the rcas opposite from the power lines... also i shield everywhere and buy the highest quality i can afford then i shield it some more with electrical tape.... also you can try one of those isolators i forget there actual name but they sell them at radioshack u can get one to try and isolate all of that feedback noise in the entire electrical system or the kind where you can isolate it just for the rca lines ... i used to work for radioshack the company sucks but some of there things are ok

It warmed up a little this afternoon and I was able to mess with it. I pulled the seat track bolt and scarped the track down to bare metal as well as the underside of the bolt. Then I attached a new ring terminal and sanded it down to bare copper. Unfortunately that didn't help. I was getting some static upon start up so I decided to move the remote wire. I pulled it out and isolated it from the other wires and still the same problem. I pulled the HU from the dash and then I moved them around and I did notice a slight change in the pitch of the sound. I didn't have time to pull the center console up to seperate the power line from the RCA's and Speaker wire.

The thing is when the unit is at 01 on volume there is no hum, it only happens at 00 or when switching between EQ setting or radio stations. It seems that when the unit should not be putting out a signal is when I get the hum/hiss. I realized that the problem didn't occur as long as at least one set of speakers were directly connected to the HU. I will try that first and see what happens before pulling up the Center console.

I was wondering if that solves my problem temporarily, can get attach a ground loop isolator directly to the HU speaker level outputs?

Always use shielded RCA's, does your HU make the noise if you put it on mute? or just when it is at 0?

The model radio is a Pioneer DEH-P4800MP, doesn't have a mute button. I can turn it all the way down to 00 and get the his; almost stone silent between 05-01 and then at 00 hiss. I don't think I used shielded RCA cables? Where can I get them?