Stereo Question

[Rick]

Ive just fitted a two channel amp into my car. However when I switch it on, it hisses really badly and then pops when I actually start the engine. Ive run the RCA cables and the power cable down the same side of the car, could interference from the power cable be affecting the sound signal.

Cheers in advance,

Rick

 

[Pysco]

Possibly, RCA cables are shielded so it shouldnt cause inference, I run mine next to each other and theres no adverse effects. Its possible you have a ground loop somewhere, where is the amp mounted?

 

[Rick]

The amp is mounted in the boot. It was difficult to find a earth, but I losened off one of the seatbelt mounts and filed off the paint overspray so that there was a good contact. However because the connection at the end of the earth cable has quite a small loop in it I couldnt put the bolt straight through it so I had to clamp it down with the bolt against the metal.

Rick

 

[theICEman]

Chances are it is a ground problem. It might be due to a bad earth or interference, but it could also be due to the ground loop thats formed between the head unit ground point and the amp. The best solution for this is a ground loop isolator, which kills the extraneous noise without affecting the audio signal. These can be had for a few quid from a specialist car audio dealer, or can be ordered online from Maplin. The popping when you switch it on is fairly normal on any amp which doesnt have a particularly soft turn-on. Any JBL models are notorious for this problem (Loud & Clear have a 60dB turn-on), along with a lot of other brands.

 

[LOUDWILLIAMS]

alrite mate, theres a big system in mine and ive ran the rcas down the opposite side the the power lead. and theres no probs.

 

[Rick]

Thanks for the advice people, but Ive managed to trace the problem back to some faulty RCA leads, so Ive got some new ones now and all the interference has gone.

Rick

 

[Nick Read]

Well Ive got a JBL 4 channel amp and it has never popped even once!

 

[theICEman]

Is it Loud & Clear? And by the way Im by no means dissing the quality of JBLs amps, theyre actually very good quality and the RMS ratings are among the most accurate of any mainstream audio manufacturer! But it is well documented in audio test data that the JBLs have a relatively loud turn-on. This just means you get a quick pop thru the speakers whenever the amp is turned on by the remote.