Problem with new Kicker ZXM700.5 amp

[deafgoose]

I replaced my stock ZX200.4 with a ZXM700.5 and after installation I tested everything and it was perfect. That was until I started the engine!

I am getting a really high pitched sound coming our of my speakers while playing music with the engine on.

With the engine off, its perfect.

Any idea what would cause this problem?

[cab13367]

I replaced my stock ZX200.4 with a ZXM700.5 and after installation I tested everything and it was perfect. That was until I started the engine!

I am getting a really high pitched sound coming our of my speakers while playing music with the engine on.

With the engine off, its perfect.

Any idea what would cause this problem?

I had the same issue. My HU ground was connected to the starting battery neg and my amp's ground was connected to my stereo battery neg. I moved the HU ground to the the stereo batt ground and the noise went away. So check that every component in your stereo system is connected to the same battery, both pos and neg, and the noise should go away.

[moombahighrider]

Al is right on with his suggestion. You are dealing with alternator whine, which is simply electrical interference. If you still have some of it after checking your ground, you can get ground loop filters that go inline with your RCA cables. They will help a great deal, too.

[EarmarkMarine]

deafgoose,
Try and avoid using a ground loop isolator until the final solution because it still leaves the gound or supply loop intact.
First, check that your input gains are not too high on the amplifier. Good tuning often resolves this especially if this amplifier is wired the same as the previous amplifer.
Next, if you have dual batteries then make sure that no components are wired battery-direct. Everything should come from the dual battery switch common (output, not ground) post. This automatically eliminates a potential supply loop. If using a VSR then the scheme may be different in which case everything audio goes to the same battery.
Next, sometimes the long route via the factory harness that supplies the HU introduces too much resistance. A new 14-ga to 12-ga B+ and ground can be run either to the same supply source or to the terminals, or closest to the terminals, of your largest amplifier or in this case the new amplifier. To close the noise inducing loop, and technically speaking, having the least potential between components in the signal path is more important than the supply path. However, if the amplifier is in very close proximity to the battery then this distinction is less relevant.
Next, verify if the amplifier has a high and low input selection switch and make sure its set to the correct setting.
Its always possible that a long and coincidental routing of the RCA cables and power cables could induce noise but its very improbable.
A single shorted speaker wire, especially after a crossover series capacitor where its difficult to measure, can induce noise into all channels. You can simply remove all speakers and add one at a time until the noise re-appears.
Those are the basics. Its usually a very quick and easy diagnosis.

David
Earmark Marine

[ian ashton]

I had this before I switched head units. Run an 18awg wore from HU ground to Amp negative. Problem solved.

[deafgoose]

Hmm.. Interesting.

Well my original amp had both the amp and HU grounded to the negative terminal on the battery.

You guys are talking about "stereo battery ground" and "starting battery ground" but I only have one battery. Where should I ground the HU?

My input gains are maxed out so maybe thats the problem.

[MLA]

My input gains are maxed out so maybe thats the problem.

Id start right there. Id say set them about the 11 oclock position.

[deafgoose]

Id start right there. Id say set them about the 11 oclock position.

Update: I turned down the input gains to the 11 o'clock position and it made absolutely no difference.

Where else can I ground the amp besides the negative terminal on my battery?

[MLA]

Try a new set of RCA cables. Just run them direct from the source to the amp. Do not bundle them up like a permanent install, just lay them across from A to B and try that.

[philwsailz]

Hey 'Goose-

A few questions for ya:

1. DId you use the power wiring that was there already, (200.4) or did you install new 4ga wire for the 700.5?

2. Where is your head unit power wiring connected?


I ask these two questions first since the noise you are getting is associated with a voltage potential difference between the head unit and the amp. Using the too-small stock power wiring can cause this. Additionally, we want to take steps to make sure the head unit is at the same voltage potential as the amp. This often gives us the opportunity to try the very simple re-wire job that David already pointed out, specifically taking your three head unit power wires and connecting them directly to the amp:

Your yellow power wire goes straight to the amp's B+ terminal. Your red power wire also goes to the amp's B+ terminal, but through a switch o relay of some sort that will allow the stereo to be turned on and off. Finally the radio's black power wire goes to the amplifiers negative terminal.

90% of the time, this simple head unit re-wire will remove the4 whine and noise you describe.


The fix will be easy, but you need to take a systematic approach. One thing at a time.... Replacing the RCA cables might do the trick, so don;t rule that out. But, check your power wiring first, then move down the chain, checkign things one step at a time. It can be intimidating for the average Joe, kind like looking under the hood of a car, but it really is very simple and straaight-forward.

Let us know!

Phil
Kicker