posted
So here it goes: I am running MB Quart 3ways off of a Kicker zx460 and I just installed one IDQ(still waiting for the other) with an Mmats amp. Then I decided to short the ground and move the grounding point closer to the Mmats, but now I'm hearing a whining noise when I accelerate and I'm pretty sure the noise wasn't there when I first installed the sub and it definitely wasn't there when I was just using the Kicker amp for the front setup. So my question is what could be causing this? Connections? Placement of the ground? ????? I have no idea. THanks for your help guys, I want to get it sounding perfect.
posted
When you were running the kicker before, was it all to highs, or half to highs and half to bass? A lot of the time when you have a 4 channel amp on highs with 2 different rca cables for inputs, you will get noise because the ground reference between the two cables is not exactly the same. If you are running both front and rear inputs, try unplugging the rears and see if the noise goes away. If it does you can take a rca noise filter(all it does is break the ground plane on the rca-but you still have the ground plane from the other rca) and place it inline on the rear rcas.
posted
Standard noise shooting technique should work here...
Start by starting the engine, and turning on the system. Simply unplug the ALL the rca plugs from the amps. If the noise is still there, you have noise entering the system through the power cable. Re-route it. If the noise goes away, start plugging in RCA cable UNTIL you get the noise. If you find that only one set of RCA's cause the noise, try plugging that set into the other amp. If the noise is still there, replace that set, and try again. If replacing those doesn't help, and you have processors (x-overs, DSP, bass cube, whatever)upstream from the rca inputs on the amps, bypass that first piece, and see if the noise goes away. If it does, you may have a faulty ground trace in that piece. If it doesn't, go to the next processor upstream and do the same.
If you get to the last processor and the noise is still there, try unplugging the rcas from the headunit. If the noise is still there, try re routing the RCA's. If, after unplugging the rca's at the deck, and the noise goes away, you could have burnt trace in the head, or simply a bad ground. If the former is true, send the deck in... if the latter, figure out a better ground, or run power and ground directly to the battery.
Let us know
------------------ Ron Hawkins
Sometimes the majority only means that all the fools are on the same side.
Use your ears to judge components, NOT your wallet! K.I.S.S.
posted
HEy thanks for the posts! I have tomorrow off and i'll spend all day getting rid of that damn noise. And maybe I'll pick up the other IDQ! Wish me luck.
posted
Ok, I unplugged the RCAs and the sound went away. So that means the power wire is all set, right? So i plugged the rcas back into the MMAts and got no noise then, one set into the Kicker and still no noise, but when I hooked the other into the kicker it was back. I also noticed the the two sets of RCAs coming out of the Kicker amp aren't two full sets of RCAs. The two pos. are connected together by a short set, then hooked up to the pos. on the full RCA and the same with the neg. and then they connect only to the front set of RCAs on the HU. I got the front setup done by a local shop. So shouldn't one set go from the amp1 set on the amp to the front RCA connections on the HU and another full set go from the amp2 set on the amp to the rear RCAs on the HU??? I don't know if I made any sense, but would this cause the noise??? THanks
quote:Originally posted by ea1: When you were running the kicker before, was it all to highs, or half to highs and half to bass? A lot of the time when you have a 4 channel amp on highs with 2 different rca cables for inputs, you will get noise because the ground reference between the two cables is not exactly the same. If you are running both front and rear inputs, try unplugging the rears and see if the noise goes away. If it does you can take a rca noise filter(all it does is break the ground plane on the rca-but you still have the ground plane from the other rca) and place it inline on the rear rcas.
posted
About your other question on the rca cables. It sounds like they used Y connectors to turn 1 set of rcas into 2. The only real drawback to doing this is the fader on your deck wont fade front to rear on that amp. If the amp is running fronts and rears, and your HU has 2+ sets of preouts, I would run another rca to have fade(this wont cure your noise problem though). If the amp is running mids on two channels and tweets on two channels, then it would be pointless, just leave it like it is. On the noise problem, I have had the same problem before with many amps(including the 4 channel kickers) The ground loop is actually being created inside the amp because the amp signal has two different grounds(front and rear inputs). The only way I could fix it without going into the amp was to break the ground plane on one of the rcas. The easiest way to do this is with a rca noise filter/decoupler.
posted
Have another question: How would this be connected?
From Hu Front red to y connector---- the y goes black and red From Hu Front white(black) to y connector-- same thing
On the amp they were in the Amp1 and Amp2 rca inputs.
Amp1 Amp2 O red O red Right O black O black Left
How should they go back??????????? I was messing around with today for a few hours and now I'm not sure how it originally was.
Also I am using a crossover Module on the amp(SWX for the mids) and when I took it out and turned the HU on, the right set of speakers didn't turn on. Now this crossover is only to crossover the 6.5" mids, so this shoudln't have happened right? Shouldn't I have lost only the mids?
posted
It really depends on how they wired the outputs of the amplifier. But if they did it like I would, then take the front red rca that is Y'ed and plug them into the reds on the amp. Now do the same for the other side, and you are done
Now for the second part. It sound like they wired it with the lefts on the fronts and the rights on the rears. If this is what they did i would make sure that both the internal crossover for the fronts(you cant change this one) and the swx chip for the rears are the same freq and the same slope. I would bet they aren't, I know the swx has 24 db per octave slopes, and I believe the internal crossover for the front is either 12 or 18. If they aren't the same, I would rewire the speakers so that the lefts are to left and the rights are to right.
posted
I tried to wire the red y to both pos. on the amp and other to the negs on the amp, but I lost teh ability to fade left to right and vice versa. I tried to plug the red y's red to amp2 red and the blk to teh amp2 blk and other y's red to the amp1 red and blk to blk and it seems ok. Could this be right? Balance adjust works and it sounds ok. Thanks
posted
It all depends on how they have the speakers wired to the amps. But if youve got it working right, then you figured it out, there isn't much you could do wrong there.
posted
I thought it was gone, but I just heard the faintest noise pulling out of the driveway while it was paused. So what were you saying I should use? A noise filter for the RCAs? Does it hook directly in line with the cables? Thanks a lot for your help!
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