gem225

Hey everyone,

I recently purchased a 1976 corvette that the prior owner had installed audio on. Problem is I can't seem to get both the sub amp and the speaker amp to coexist together.

There currently is no head unit. Instead, there's a quarter inch to RCA cable that runs back to the amps. There's a split that separates it into 4 l/R cables, two for the speaker amp and two for the sub amp.

The sound system is fine if I only plug in one set of RCAs -- a L/R to the speakers works great or a L/R to the sub works fine also. However, when all four are plugged in only the sub comes through.

Currently, the power lead is wired from the speaker amp, into the sub amp, on to the positive terminal of the battery. The ground is wired from the speaker amp, into the sub amp, into a ground on a killswitch for the ignition. The remote is wired to a switch, then on to the positive terminal of the battery.

I'm not sure where to start on rewiring this -- is there an issue with the power/remote/ground leads or is this type of thing something where the amps or speakers are improperly grounded? It's just weird that the amps work fine independent of one another, but won't place nice together.

Thanks for any thoughts!

Mark Riles

Start slow and simple. Trace the 12V, the ground, and the remote turn on, for both amps. Find out where they go and test for continuity. Check the fuses in the amps. Check the wiring at the terminals. Usually the 12V is right next to the ground and even a stray strand can cause the amp to go into protect. Once you find the ends of all the wires you can use a 12V test wire and a ground to check the remote turn on circuits of both amps. Check the remotes, make sure they both have power and ground, and check the RCAs for proper phase. If you are still experiencing problems then suspect the head unit you are using to test the amps.

73Corvette

I'm kinda slow but, if there is no head unit what are you plugging the RCA's in to?
I would ground the amps to the frame...or the battery..

spedaleden

there's a quarter inch to RCA

Do you mean you have RCA's or a 1/4 inch female input to RCA. Sounds like the former owner plugged a Ipod to amps maybe.

MalibuVLX

We do that in our offroad rockcrawlers. Take it out when you are done. No muss no fuss. works great. Just does not charge the ipod w/out some mods and different RCA/plug connection that has 12v built into the harness.

7T1vette

I don't know what kind of amp power you are trying to produce, but if more than 100 watts, you need to run dedicated power and ground cables directly from the battery to both amp systems. They also need to be fused separately. And, for every 100 watts of sound power, you need another 10 amps of alternator power. So, if your alt is a 63 amp unit...and you have 400 watts of power [capability] from the sound amps, you will need as least 100 amp alternator to power it.

P.S. A larger alternator also means that the power cable from it needs to be larger, too.

Jrventure

Just changed the battery on a '82 Corvette.
The aftermarket radio, sub woofer and etc are now sounding terrible with a lot of static. Did I connect the wire wrong?
The battery box is so small and the guy who installed this, the owner before me had the stereo installed.
What goes to positive and what goes to negative?
Thanks

7T1vette

Do you have a friend with some electrical skills? DC voltage connections for stereo systems are not difficult, but if you are asking what connects to positive and negative, then I think that you need some skilled assistance to solve your audio problems.

I will tell you that, in general, modern radio head units do NOT use chassis ground on speaker (negative) connections. Most modern units have 'floating' (non-grounded) speakers. The speaker wires are only connected to the wiring lugs; and those are isolated from the speaker frames. Of course, reading this post, we would have no way of knowing what components the previous owner installed in the car...or whether they were even compatible.