After I had my little 4 ch amp installed, for some bizarre reason the stereo is now front to rear as opposed to left to right (ie if you set the balance of the head unit to the left, only the rear speakers are heard, right the front).

The head unit is running the amp via an RCA splitter (2 ch to 4 ch), and the output of the amp to the speakers is wired correctly. It's doing my head in :bash:

I noticed that if i set the fader to the front all 4 speakers die, so I guess the rca's on the head unit run off the rear channels.

Guess the amp was cheap for a reason..

I dare say you have the left channels connected to one end of the car and the right channel to the other...

Sounds like your plugs are just the wrong way around, try swapping them to get the fade right...

if you only have 2 rca coming out of the back of your hu, you will have for example a rear left and rear right + AND -. this meas that if the 4 amp in channels are running of these 2 pre outs, there will never be any fade control because there is only a rear output. this explains why when you put all the fade to the front, the speakers cut out.

for the front and rear fading when changing balance, this is because you have the rear speakers hooked up as the left hand channel and the front speakers hooked up as the other channel. if the rear is heard when set balance to left, you need to swap the rca's on the rear right and front left over, on the amp input. this will give you balance correctly.
becasue of your headunit, you will never be able to change fade without making a physical adjustment on the amp or a seperate balance control.

Tough one to work out with out seeing it, But I will take it for granted that all RCA's are connect to the right colour.
And the H/Unit has one RCA pair out, or you have a high level to RCA out.

But,

It sounds like the speaker wires are mixed up, Disconnect your RCAs on the amp, Set the H/U to middle balance and fade. Make Sure the volume is tuned up Some.

Disconnect speaker wire.

Start with Channel 1 &2. Lets call that Front. Connect White (Left) RCA, Connect speaker wire one pair at a time to channel 1 till you get sound from Left front.

Channel 2, Connect the RED ( the white RCA's Pair) and find the wire that makes the front Right speaker work.

Channel 3 & 4 connect White RCA and find the Left rear speaker. Then connect last red and remaining speaker wire.

Top Tips.
The speaker wire with the Black stripe is the + positive.
Balance will work from the H/Unit.
Fader will now work from the Gains on channels 1&2 and 3&4
Mark wires so if you pull it out its easy to reconnect.

The guys above have got it!

When a headunit has only 1 RCA output it is either rear or sub out.

That means if you fade to the front, no sound. You will need to set the gains on your amp correctly to get the balance.

As above, you have your RCA's in the wrong holes. Remember when you "split" the RCA it is still the same channel. Put one RCA from one side and 1 RCA from the other in the front channels and the remaining 2 matched in the rear.

In your case the amp is not the issue, your headunit is.

Try this.

If he has used 2 x 1 rca to 2 Rca cables, you a have red and white cable coming from the left, and another cable from the right, now a red and white pair wont make a front or rear pair, but a left side or right side pair. ( one pair = Left channel etc)
So you can try, one pair (R&W) of RCA's to channels 1 & 3 , and the other pair to chanels 2 & 4.
Use the Balance on the to sort the left and right channels.

Or simply, two whites to Chan 1 & 2 and two red to 3 & 4, set balance to the left, connect the white rca that gives sound to the left, then try a red till you get sound to the left and you're sorted.

Mr C's answer with more explanation basically.

There are many things that could be going here.
I was half way into writing a method to swap around the rca's, but when I thought about it, its harder to wire the speakers than to get the RCA's wrong, so I'd have to give some credit.
He didnt say who installed the unit, if he payed for the install, he should take it back, or get the dude who installed to help again. He can play with the RCA's, but I sure we would all rather have it done right, so its probably best to start over if tis doesn't work, from the first RCA in the system and finally to the speakers.

swap the rear right rca input on the amp for the front left, its as simple as that. to get front to rear fade, all you need to do is get a high to low input adapter ($6 from jaycar) so you can plug you front output from the hu into the adapter then into the amp via rca's. then you have front to rear fade.

Thanks for all your input ppls :)

Reconfigured the rca inputs to get it sorted (isolation). My cousin did the wiring (mates rates) so he is now officially a nub cake :p Next time I'm in Qld he has some work to do :hmm:

Fader is good at level thankfully so I won't get anal about that.

Thanks for all your input ppls :)

Reconfigured the rca inputs to get it sorted (isolation). My cousin did the wiring (mates rates) so he is now officially a nub cake :p Next time I'm in Qld he has some work to do :hmm:

Fader is good at level thankfully so I won't get anal about that.

Your in NSW... Why didn't you ask for a Fellow AMC'R to help you out with the install.??

If you were from the Lower Sydney - Nowra region I would have most likely to have been able to help...

Your in NSW... Why didn't you ask for a Fellow AMC'R to help you out with the install.??

If you were from the Lower Sydney - Nowra region I would have most likely to have been able to help...

Thanks for the offer! In Armidale, might as well be in the land of Far Far Away :)