Amp hiss, where is it coming from

[jonfo]

I replaced a JL Audio 6 channel amp with a new one under warantee. After i replaced it the new amp makes the speakers hiss. I didnt change any of the wiring that i know of, and i put the inputs and settings to the same level as the old one. I just disconnected the power and ground from battery, reconnected all the wires to the amp. If i put the engine in neutral and rev it up the hiss is proportionate with the rpms. Somebody else told me it could be the input RCAs to the amp are too close to the power line, but i didnt change any of the wiring. thanks for any input, Jon

[wetsounds1]

RE: Amp hiss, where is it coming from

There are different tolerances in manufacturing. the new one seems to be more susceptible to engine noise. If nothing else changed, it would be the input of the new amp. It could be bad. Or you may have to re adjust your gains. even though it is the same amp and brand. The slight difference on input gain structure could be hotter on this new one so even though they look like the are the same setting, it is actually up a bit more. Most likely, it could be a bad input section. Have a dealer do a temp swap again and see what that does. If it was under warranty, could be a refurbished?

I have seen it many times. Same amp will pick up noise in one install. Swap for the same amp and brand, no noise. Then use the noisy amp in a different install and no noise.

Tim
Wet Sounds

[jonfo]

RE: Amp hiss, where is it coming from

I brought it to the dealer for some other stuff and asked them to look at the amp hiss. they installed some line filters on the input rcas. it didnt help.

i unwired everthing and rewired it and now it is working with no hiss. i havent cleaned everthing up yet, but i have a feeling it was because the inputs were zip tied to the power wire.

[SuperSquirt]

I got rid of my infamous amp hiss by briefly unplugging everything and adjusting my amp gains down a little bit.