Hello, I have a issue with my amps. I am hooking up 2 amplifiers, one to four speakers, and the other to 2 subwoofers. The speakers are hooked up in parrallel mode, and the subs are connected in series. The RCA cables are not running along the power line, however when I turn the audio on there is a low hum across everything speakers and subs. when I turn the sound up the hum is there and the speakers/subs work... I have no idea what is causing this hum, and cannot find any information as to what it is... PLEASE HELP

 

Thanks in advance!

Hello, I have a issue with my amps. I am hooking up 2 amplifiers, one to four speakers, and the other to 2 subwoofers. The speakers are hooked up in parrallel mode, and the subs are connected in series. The RCA cables are not running along the power line, however when I turn the audio on there is a low hum across everything speakers and subs. when I turn the sound up the hum is there and the speakers/subs work... I have no idea what is causing this hum, and cannot find any information as to what it is... PLEASE HELP

 

Thanks in advance!

 

you need to double check all your grounds and power supplies. Make sure there are no ground loops. Your going to have to play with fire poistion too. Is the hum there with the subwoofers disabled or disconnected. you need to play with thinngs one at a time and make sure your speaker phasing is correct.

 

nipper

 

PS found this

While not common, sometimes there is a hum problem unless the ground of the subwoofer and ground of

the receiver (or processor or preamp) are attached to each other. Sub-A includes an additional conductor

with spade-lug tails at both ends of the cable. If the system has a hum problem, try attaching the lugs to the

metal chassis of subwoofer amp chassis and to the chassis on the sending end. Normally this extra wire will

not be needed.

Thanks, but the hum is still there regardless of power being applied to the subs or not.

are you using sheilded cables. how do you have the amps grounded.

 

 

nipper

had the same issue, but didnt put much work into it, just threw on a ground loop isolator and called it good

I have them grounded underneath the seats to a bolt. Its a good ground, I dont have them shilded with anything What is a ground loop, and how can i fix it?

Do you have both amps grounded to the same spot? Try grounding them to different spots. How much wattage are you pushing? Have you thought of investing in a capacitor?

:-\ All grounded to diffrent spots, and I have a 1 farad cap. one amp is 1000 Watts, the other is 720 watts.

Does the hum change pitch at all or is constant? Does it get louder if you turn the volume up?

It goes up when i turn the volume up, but the music is still over it. I took everything else off, grounds and all, and just had the one amp to the speakers running, and it still hums. If my amp was busted would it emit sound at all?

try putting them all to the same ground. RIght now with differnet grounds you may be using th car as a giant antenna picking up all the electrical noise around the car.

 

how old is the amp

 

nipper

The amp is about 6 months old, I will try that.

I don't think it's your amps. It sounds more like it is coming from before the amps.. so maybe the preamp on the deck is going bad.. or perhaps the RCA's are going bad. Are all your ground wires the same size or larger than the power wires? Not more than 2ft long? What size power cable are you using? Fuse rating for the power wire? How good of RCA's are they? Are the outputs on the deck loose at all? Try hook up just one speaker and see if it still hums? Try hook it up to different spots on the amp.. different amp.. How is your capacitor hooked up? Power to cap, power from cap to amps, cap grounded with 2ft or less of 2ga? amps grounded with 2ga?

a GLI will isolate hums coming from the RCA outs on your deck into the amp........ my situation was the hum would change pitches with engine rev's. again, i didnt work much on it, i just found a bandaid for the problem really i'm sure, not really that tech savy but it took the noise away completely

Everything is 4 gauge wire, I checked everything on the deck, and it is all fine there. Ground wires are all less than 2 ft. Monster cable RCa's. The one speaker hums, on all diffrent spots on amp. Cap is not hooked up at the moment to try and isolate the problem.

In addition I hooked up the sub amp, and unhooked the four channel, it has power, but will not put anything to the subs??? all RCa's are fine, and the ant. is in.???

Ok, my battery cannot keep up with what I am doing, I need to take a break for a bit to let it recharge, the audio eqpt. will automatically turn off when there is not enough power. I think this is the reason for the no sound from the subs.

All right, battery back up, but the same problem. Any other ideas would be great