help with humm/amp whine

i wired a cheap line converter from my factory head unit(non jbl 2022 double cab trd sport) and wired new speakers to the amp. im getting a humming/buzzing noise and some amp whine. im grounding the amp to the rear seat bolts. ive sanded the bracket down and im still getting the feedback. do you guys think its a bad ground? i asked a car stereo shop and he said I NEED an lc2i. do you think i have a bad ground or bad rca which is leading to the noise? or is the stereo owner correct telling me I HAVE to use a lc2 to wire an amp to the factory head unit. reason im asking he said the lc2i was $200 but its only $100 on Amazon and wanted $150 install. if i dont need the lc2 and should look for ground issue i could save some money. thanks again.... havent wired car audio in over 10 years.

does anyone know if the rear seat bolt is not a sufficient ground which is leading to the amp whine?

should i look into the rca plugs or amp?

should i just buy a lc2 and start from ground zero?

 

Betting it’s that cheap LOC.

You certainly don’t need an LC2i. They’re nice, but not necessary

I would also do some testing

see if you get the hum with RCA’s unplugged at the amp.

See if you get hum with RCA’s plugged into the amp but unplugged at the loc

try just the left channel
Then just the right

See if you get the hum with RCA’s plugged into the amp and loc but the loc harness not connected

if you have a spare set of 8’ or longer rca cables laying around, hook them up real quick and see what happens.

 

Do you have both the power wires to the amp and the audio feed wires running on the same side of the truck? If so move the signal wires to the other side of the vehicle.

And have you tried turning the gain down?

 

yo thank you destin!!

ill try that this weekend

can i just cut the cheap LOC off the t-harness and just run those wires to the lc2? i did research lc2 puts out more power and helps with rollout.

lc2 is 75$ off Amazon. maybe its worth it if i swap the cheap LOC for the lc2?

also can i ground the amp to a loose piece of pipe(metal) thats not touching a earth?

 

The issue is not where you have your amp grounded. Seat bolts are fine and much better than random piping.

 

i wired
- the main 12v power and the driver speaker wires through the driver foot plate(not sure correct term/under plastic where carpet meets the door plastic
-ran the rca through the middle console
-ran passenger wires through the right foot plate

tapped the remote wire into the driver kick fuse box(add-a-fuse)

 

i thought since i was getting amp whine when driving/accelerating that maybe it was a bad ground connection

 

Hmm try turning the gains down and see if it goes away. If not then probably a cheap loc that is grounding itself thru something that picks up the alternator whine.

 

ive actually turned the gain down all the way

and honestly i made my own t harness to wire the LOC(assuming i wired it wrong)

i bought that other t harness(the one pictured) but haven't swapped it yet. i didnt want to cut into the factory harness

 

you're correct in that it 'could' be a bad ground connection. but that's only a single possibility in a scenario where the same symptom could result in a dozen other possibilities, which is why it's important to test what destin_meeks posted.

a hum/whine only means that there's extra voltage passing through the rca's that shouldn't. a hum/whine will result from too much voltage passing either direction through the audio cable. it could mean the ground is too good at the amp, it could mean the ground is poor at the amp. it also could mean the loc is adding extra resistance, or not enough resistance. or it could be the rca's getting an induced voltage from an entirely different source. every one of these things has a different process and steps to correct.