Electrical whine

[Boonejeepin]

Any advice on why I have a new electrical whine from my sub amp?

The problem just started and I have not modified the system. The whine happens with the engine running and when the fuel pump primes at key on.

Whine disappears when RCA cable is unplugged from eq or amp. I also tried a jumper RCA from the eq to the amp and the noise was still there.

Any suggestions on where to start?

Thanks!

[MLA]

Give us some additional details about the system. Try running RCA direct from head-unit to sub amp.

[David Analog]

That's unusual that you would have a pronounced whine on the subwoofer amplifier that you do not have on the fullrange or highpass channels of other amplifiers since the sub amplifier lowpass filter would normally mute the high frequency whine. A 'hum' would be more typical on the sub.
One initial step is to short the sub amplifer's RCA inputs and check for the noise. If the noise remains you know that it is an issue either within the amplifier or in the sub wire. All it takes is one tiny shorted strand. If the noise is eliminated then you know the culprit is upstream in a component or a component to component relationship issue or a grounding issue.
Then triple check the quality of the sub amplifier's primary ground. Also, check the ground quality of both batteries.
Check for good battery voltages and check 'ALL' audio components get power from the identical physical point and identical ground point. No exceptions.
Make sure the RCA cables are well seated.
Whether a HU or EQ is feeding the amplifiers, measure the resistance between the unplugged RCA ground shield and the true primary ground to make certain that all RCAs show the consistent value.

[Boonejeepin]

I am rerunning my power wires to clean up the original install mess. I just added and added without keeping the install as clean as I would like.

I have a battery selector switch (1, 2, 1+2, off). Should my stereo power wire be connected direct to battery 2 + post or connected to the common post on the battery selector switch?

I have all stereo grounds to battery 2 - post.

[David Analog]

If you want to avoid all future B+ supply conflicts and make the use of the selector switch more unconscious, as it should be, then everything (100% of the audio components, the helm buss, and the starter/alternator feed) should be connected to the common/output post of the battery switch. And nothing should be wired battery-direct except for the switch #1 & #2 terminals and possibly the bilge pump & float switch if you moor the boat.

[Boonejeepin]

Ok - thanks David!

Not sure what the change is but now I have a whine from the cabin speaker amp with fuel pump running. Whine goes away when I unplug RCAs from cabin amp. Whine is present when I use a different RCA cable from the EQ to the cabin amp amp.

[Boonejeepin]

Give us some additional details about the system. Try running RCA direct from head-unit to sub amp.
I'll try this when Amazon delivers all the new wiring components. I decided to rework my tangled mess of wiring. System is torn apart for a couple of days.

[liquid_acid]

Interested to find out the problem. Keep us posted.

[Boonejeepin]

I never use my headunit as an audio source but I use the headunit remote turn on lead to turn on the amps. The headunit is still on the factory wiring circuit. Can the remote wire/headunit being ground and accessing power through a different path than the amps cause issues?

Thinking of wiring the headunit remote wire to a relay to turn on the amps. I would wire the power and ground for the relay to the same power and ground sources for the amps. My thinking is this would provide "clean" power for the remote turn on at the amps.

Would this work or should I do something different? I have no plans to use the headunit as an audio source. I just want the easiest path to use the dash stereo switch to turn on/off the stereo.

Thanks again for all the advice.

[MLA]

Boon,

You easily bypass the head-unit and trigger the amps on directly. Use the red switched 12 that triggers the head-unit now, to trigger your relay that would supply the 12v trigger to the amps. Since that amp turn-on circuit is not in the signal path, where that 12v comes from, is not as crucial as the actual head-unit/EQ constant B+.

[Boonejeepin]

Thank you MLA.

[Boonejeepin]

Got everything cleaned up and tidy. Still a slight whine with fuel pump running but seams better. Can't wait to test on the water with the engine running.http://tapatalk.imageshack.com/v2/14/09/04/8ce2167ecad6821176f9fb218f2d8972.jpghttp://tapatalk.imageshack.com/v2/14/09/04/c002880863eb26857b931dd66094dea6.jpg

[jstenger]

Got everything cleaned up and tidy. Still a slight whine with fuel pump running but seams better. Can't wait to test on the water with the engine running.http://tapatalk.imageshack.com/v2/14/09/04/8ce2167ecad6821176f9fb218f2d8972.jpghttp://tapatalk.imageshack.com/v2/14/09/04/c002880863eb26857b931dd66094dea6.jpg
I do not see any fuses. Did you use any?

[Boonejeepin]

I did. I have a 200 amp circuit breaker within a foot of the battery switch for the main power line to the distro block and also a fuse on all three power wires going to the amps immediately after the distro block. The fuses for the individual amp power lines are hidden behind the amp board.

[Boonejeepin]

Thanks MMandley for talking me through this today.

I think I tracked the noise down to the EQ.

Input from headunit disconnected.

Phone output direct to amp input rca - no whine

Jumper rca from eq to amp - whine

All eq inputs disconnected, rca jumper from eq to amp - whine

[mmandley]

No problem, glad to help

[MLA]

Thanks MMandley for talking me through this today.

I think I tracked the noise down to the EQ.

Input from headunit disconnected.

Phone output direct to amp input rca - no whine

Jumper rca from eq to amp - whine

All eq inputs disconnected, rca jumper from eq to amp - whine

Does the EQ have adjustable input sensitivity? If so, how is it and the amp gains set? Higher the gains, the more the system is open to unwanted noise.

[Boonejeepin]

Does the EQ have adjustable input sensitivity? If so, how is it and the amp gains set? Higher the gains, the more the system is open to unwanted noise.

I have a Clarion eq and it has adjustable gains for the aux in. Same noise with the aux gains up or down. Same noise aux RCAs plugged in, or not. Only drop the noise when cabin amp RCA line is unplugged from the EQ.

[MLA]

Ok, so the main gain is fixed, but the noise is when the EQ is in either main or AUX modes? That puts it on the output side and would make sense if its heard in both the front and rear zones, since its a single output thats split.

[Boonejeepin]

Correct noise for both main and aux modes.

The noise is really only noticeable now when volume is all the way down and fuel pump is running. I can live with that. It's not really loud at all now.

I haven't started the engine yet. Hope the loud noise does not show itself then.