Hey, today i decided to install another amp and another sub that i had lyring around, when i took them out of my old car they worked fine. I ran both subs in mono on each amp. now im getting a loude humming sound coming out of the old amp when i run it to eather sub, it doesnt do this in my old car, i even set it up in my old car sence i still have the harness in it. To rur both amps, a four gage wire is coming off the battery, and about a foot of 12 gage wire going off of it to the amps. i have the same set up to the ground. When i run just the new amp i get a small hum, but its not nearly a loude as the old amp. Im pretty confused at what it is, but i have a fealing it is the right input wire off of the deck. any ideas of what to check?

check the voltage of the 2 outputs on the head unit they should be 4 volts

are your power wires and RCA wires running down the same side of the vehicle? If so seperate them. What size amps are you running? I would suspect 12 gauge power wire to be insufficient for anything above 300 watts. 2 amps splitting 4 gauge wire can't be fun either. I was running 1 gauge wire to 1 amp and it LOOOOOVVVVVVEEEEDDD it. also as mentioned above make sure your Head unit voltage is high enough.

Originally posted by ThePerfectShift
are your power wires and RCA wires running down the same side of the vehicle? If so seperate them. What size amps are you running? I would suspect 12 gauge power wire to be insufficient for anything above 300 watts. 2 amps splitting 4 gauge wire can't be fun either. I was running 1 gauge wire to 1 amp and it LOOOOOVVVVVVEEEEDDD it. also as mentioned above make sure your Head unit voltage is high enough.

12 guage is insufficient for anything over 100 watts, get bigger wire, you'll fry the amp, subs or both by choking off the power supply.

as stated before the humming is most likely interference from the power and audio cables running too close together, they need several feet of seperation even for the best audio cables not to pick up noise from the power cables