n0rad

iTrader: (1)

I just installed a 4 channel amp (JBL GTO 75.4II, 104 rms) and front components (JBL Power P650C, 90 rms). I turn everything on and there is a hissing coming from the speakers when the volume on the deck was set to zero. so i turned the gain down slowly and found that the hissing stopped when the gain was set to its minimum. now in order to get regular listening volume on my deck i have to turn it to like 2/3's its volume, and thats not even super loud.

so am i missing something? is this normal? In my head this amp should be able to power the speakers no problem with the gain turned up even a little bit. Is my noise coming from somewhere else?

Much appreciated.

zzzzzzz

iTrader: (5)

where/how is your set up grounded ?
are the rca's next to the power wire ?
are the rca's old ?

n0rad

iTrader: (1)

its grounded to my chassis in the trunk and then the deck is grounded from stock ground.

the rca's are only next to the power/ground wire right before they go to the amp. for the rest of the car my power is on the driverside and my rca's are down the center.

they are new top quality stinger cables.

MTT

iTrader: (17)

Try running a separate ground from your deck instead of using the stock ground......what kind of deck?

n0rad

iTrader: (1)

its a sony deck but... i tested to see if it was the deck causing it so i unplugged the rca's from the amp and the noise doesnt change. could this come from my crossovers? they are mounted under the dash.

zzzzzzz

iTrader: (5)

try adding a (neg) to the rca's
also try moving the amps neg to a new place
form the deck it goes to the amp or something like a eq ?

n0rad

iTrader: (1)

i connected a small speaker to one of the channels on the amp and disconnected the rca's. the small speaker made the same level is hiss as my new ones. so that eliminates my deck,rca's,speaker wire, and crossovers right? so now it could be my power/ground wires themselves right? ill try relocating my ground.

zzzzzzz

iTrader: (5)

try new ground and if that does not work bench test the amp

n0rad

iTrader: (1)

ok so this is where im at. moving my ground would be way to much work so i decided to go straight to the bench test. so i took out the amp from the trunk, placed it in front of my car, ran 2 line of 14 awg wire from the battery to the amp for power/ground, ran the remote wire from my trunk to the amp, attached a small speaker, turned the amp on and i got the same hiss ERG!!

any ideas? faulty amp? faulty battery? incorrect benchtest?

thanks so much

n0rad

iTrader: (1)

sorry for double post.

EDIT: When an amp is powered up with no input should the speaker attached to it be dead silent or have at least some sort of hum?