hifonics zeus z6000 noise problems

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hi everybody.
i have this amp and it have noise problems
alternator whining and click noises when open turn signal or alarms are audible.
when i turn on the amplifier's low pass xover whining stops but the clicking is still audible.
i am sure it's the amp because i have 4 more amps and it's they only one with this problem.
any ideas?

 

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when i remove the rca input the problem stops.could be the cables?
it's next to the crossover and the are only 20cm long.
ps.if i lower crossover gain and open amplifier gain the problem is worse.
with amplifier gain low and crossover gain high it's minimised.

 

[Perry Babin]

Could the RCAs for that amp be pinched and grounded to the chassis?

 

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i did it but no change.

 

[Perry Babin]

Did what?

Do you get the same noise if you unplug the RCAs from all amps and plug the RCAs from another amp into this amp?

 

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i used a single wire from rca to chassis.
i have used it with another rca and the noise is the same
but haven't used it with all the rest amps disconected

 

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reading around for info i see most times ground loops cause that kind of problems.my head unit is powered by the cars plug.
is it possible the ground to be worse than car chassis where the amps are grounded?
the noise is there only with one amp but maybe it's more sensitive from the rest.

 

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i grounded the head unit to car chasssis but no luck.
i am afraid it's the amp not the instalation.

 

[Perry Babin]

Disconnect all RCAs from the head unit and from the amps. Measure the resistance from the shields of all RCA cables to ground. None should make you meter change from whatever it reads when the probes are open. Is that what you have?

With the RCAs disconnected from the head unit, confirm that all REC output shields read 0 ohms to the case of the head unit.

With one of the RCA cables that was feeding the other amps, feed the noisy amp from one of the RCA outputs that you were using for one of the other amps.

It's important to make absolutely certain that the problem is not something other than the amp before you start troubleshootng the amp.

 

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i have done step three because amp was driving the subwoofer before and now midbasses.
different outputs and different rca's with the same problem.
i will do the rest too asap

 

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i took the measurements.
no rca is shorting to ground
and all REC outputs read 0 to headunit chassis.

 

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i installed the amp at another car and had same problem.i am sure it's the amp.
any idea what to look for?

 

[Perry Babin]

Is there any DC voltage on the RCA shields of the amp (no RCAs plugged in)?

What's the resistance from the RCA shields to the amp's main ground terminal?

 

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between rca shield and ground resistance is infinite.
dc between rca shield to rca hot or amplifier ground or something else?

 

[Perry Babin]

Post a photo of the inside of the amp.

 

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here it is

 

[Perry Babin]

Resistance across RP23?

Color bands on RP23?

Does one end of RP23 directly connect to the RCA shields and the other end connect directly to the main ground terminal?

Resistance from RCA shields to either of the non-bridging speaker terminals?

 

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RP 23 connects to main ground and the other connects to non bridging speaker terminals.
rca shields have infinite resistance from rp23 and speaker terminals.

broken trace under pcb maybe?

 

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rp23 the speaker terminals side connects to cp23 but the other side of cp23 doesn't connect to rca shields

 

[Perry Babin]

I don't know this amp but the RCA shields with the circuit it appears to be using generally connect to the non-bridging speaker terminals. It could be a broken solder connection on the RCA jacks (or elsewhere), a broken wire, a connector not plugged in completely or even a broken trace. Check the areas around the small RCA board first. You want to avoid removing the main board if possible.