Left speakers hissing?

[azzfox]

Hey guys, I finished installing a 4 channel amp into my N13 Pulsar last night to find that the left speakers (front and rear) make a hiss/whistle noise that varies but doesnt get louder with volume. They also 'pop' when you switch between volume 00 and 01. The headunit is a Pioneer DEH-P4950MP, the amp is a Response AA0451 (Jaycar) and the wiring is your standard Aerpro 8ga kit from Autobarn.

Ive left-righted the RCA's and its still only the left speakers so I'd say its the amp at fault. I also noticed that if I physically touch the amp with my hand the noise noticeable changes! The RCA's arent ran near the power wire, the earth is clean and it makes no difference with the ignition on or engine running.

The amp has 12 months warranty so Im thinking about taking it back and maybe trying another.

Thoughts?

[jacksoncroucher]

easiest thing to do is probly get your amp tested on the spot by jb hifi or an udie shop, i took mine to jb and they tested it and sore it was faulty and gave me a new one strait away, at least then you can rule out the amp if its not the problem

[azzfox]

Problem is I diddnt get it from JB so they wont give me a new one . Neither will any audio shop and Jaycar will probably send it off for testing. As for ruling out if the amp out Im certain it is that. I might just plug my ipod in with a 3.5mm to RCA cable splitted across the 4 channels. Then if it still does it well the speakers worked fine before hand and speaker/power wire cant be faulty

Possibly problem with them sending it off for testing if they pull the amp apart they MIGHT void the warrenty. The screws that hold the side covers on were too long and would bottom out before they would be tight. So I filed them down. Nothing to do with the workings of the amp but yeah lol. Well it was only actually only 3 of the long screws. 1 of them was the right length so I filed the other 3 to match the length. I wasnt gonna drive over an hour back to jaycar to exchange it

[DAKSTER]

I see its 50wx4.. you are probably exceeding the power handling capabilities of an N13 Pulsar by about 150W....

[azzfox]

Wait, wait, wait... did you just make a funny?

On a different note its the amp. At first I thought it wasnt doing it but with the volume right down it did. Just not as loud. Then as I would wave the iPod around the noise changes. So the signal cables are sort of acting as aerials picking up interference. Back it goes! Apparently the silver amps were the better ones.

[azzfox]

Finally took it back on the weekend and changed it over. The new ones not much better. The noise is still there, its not as loud, but its though all the speakers now . The salesman at jaycar was helpful though. I explained the situation and he basically handed me a new one. I asked if they get much of them back and he told me they do get a few here and there but other than that he owns 3 himself. So on the weekend Im thinking about making a trip back down and hopefully get the same person to check it out while its in the car. You dont notice it with a bit of volume but its still annoying lol

[StoneX]

Sorry for not seeing this earlier.

Pioneer head units have an internal fuse on the RCA ground track (on the circuit board) which can blow if the RCAs are connected or disconnected while the stereo is running. This then causes the pop from 0 to 1 on the volume and a whining noise with the car revs. You can test if it is this in two ways which are explained below;

1. Get a multimeter, unplug the head unit completely, measure the resistance from the head unit chassis/shell to the outer ring of the RCA sockets. It should be 0 ohm, or under 1 ohm.

2. Get a bit of wire, strip both ends, slide head unit out of dash but leave it connected to everything, touch one end of the wire to the head unit chassis/shell and the other end to the outer metal ring of the RCA that is plugged into the socket on the head unit. Then adjust the volume from 0 to 1 or have the car running to see if the whining noise goes away.

[edit]
Also, the solution is to have Pioneer repair the fuse or if you don't want to spend any money, somehow permanently affix that wire to the head unit.

[KAL SPL]

On the first amp you should have swapped the speaker wires on the amp to see if the noise went to the other side , would have isolated the amp then.

[azzfox]

Stone - Ive always made sure it was off first for this reason. 99% sure the head units fine but I will give that a shot tomorrow. When I plugged my ipod into it with a 3.5mm to RCA cable and it still made the noise it was a dead give away to me that it was the amp. But the volume pop could have something to do with the head unit. Also with the engine running or not it makes no difference. The funny thing is the more I physically touch the amp the more the noise disappears. It might even be worth trying the earth test on the amp. Same principals apply?

KAL - I diddnt think to try swapping speaker wires but I did swap the RCA's which made no difference.

[azzfox]

Ok here we go...

Head unit - 0.1-0.2 ohm on all outer rings to shell.

Outer ring on amp to clean metal seat bolt - 900+ ohms.

Same seat bolt to door hinge - 0 ohms.

Earth wire on amp to seat bolt - 0 ohms.

Piece of wire from seat bolt to outer ring on amp - noise mostly disappears.

Piece of wire from seat bolt to metal screw on amp - speakers crackle. (Not sure if this means anything)

[azzfox]

Ideas before friday? Keen on driving back down and hopefully get the same guy who exchanged the amp last time to come out and have a listen, seeing hes got 3 himself. I know its just not me because last weekend I picked up some friends and one in the back said my speakers crackle lol. Sort of let down a bit after hearing good things about these amps over the years and then I get 2 faultys in a row . Maybe they got a bad batch or something.