Voltage from Head Unit is below 12v

[psych0ticnemes1 5,000+ posts]

When testing the remote turn on lead at the amp, it is only seeing 11.1 volts. When I run a cable from the positive terminal to the remote turn on terminal, I get 12v with the car off and 14.3 with the car on.

It is obvious that my head unit is not providing a 12v signal to my amp via the the rem wire. What can I do about this? Can such a low voltage cause a problem for some amps that require at least a 12v input signal to work properly? I have had problems in the past where even if I turn the gain all the way up, I couldn't reach the correct voltage. Could this be why?

Thanks.

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[bamaboy 5,000+ posts]

is it not turning amps on?

i would think 11v would trigger it

an easy fix is just wire in a relay

the remote wire does nothing but send positive voltage to trigger the amp to turn on, it has nothing to do with output voltage

 

[Proximity 10+ year member]

You could probably wire in a relay. though I'm not sure if 11.1 volts is enough for a relay.

 

[ejschultz 10+ year member]

11.1 is definitely enough for a relay. just read the specs on the relay before purchasing it and make sure that 12-14.4 volts can be handled as an output and see what type of input signal it requires to activate.

 

[Stephen_c 10+ year member]

You could probably wire in a relay. though I'm not sure if 11.1 volts is enough for a relay.

i tested my relays they turn on around 5.7 volts //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[Proximity 10+ year member]

Yeah I figured they were sensitive enough, but wasn't sure.

 

[psych0ticnemes1 5,000+ posts]

is it not turning amps on?
i would think 11v would trigger it

an easy fix is just wire in a relay

the remote wire does nothing but send positive voltage to trigger the amp to turn on, it has nothing to do with output voltage

The amp definitely turns on, but when I crank the gain I can only get about 8 volts. I only have this problem with one amp. When I swap this amp out with a different amp can reach the correct voltage even though the input voltage is so low.

Can such a low input voltage cause an amp to not put out the correct power?

 

[bamaboy 5,000+ posts]

no, its just a on/off trigger

so a different amp can reach higher voltages?

if so, then you figured out the problem, you have a bad amp, take your amp and put it in a different vehicle and see what it can do

if both amps do it, i would check RCA's, or the Outputs on the HU

 

[psych0ticnemes1 5,000+ posts]

I checked the internals, they look fine to me. It does power the sub, but even if I crank the gain it doesn't put out much power. When I turn the gain it does increase the voltage so I don't think the amp is bad. Any idea what else it could be?

Edit: Do some amps require the gain knob in order to reach the correct voltage? It sounds stupid but it could be a design flaw.

Also, how do you check the rca jacks in the amp itself? I wonder if the amp's rcas aren't receiving the correct signal. I know the rca wire works because it works fine for my other amp.

Thanks Bama.

 

[nuugen 10+ year member]

1. The remote-in voltage has nothing to do with input/output voltage--if the amp turns on with the remote, it is on..If not, you need to use a relay.

2. The amp can still be bad, even though it is working, if it is not putting out full rated power. You put another amp in place of it and that amp works fine, so it is not the wring or input problem.

3. I have seen some amps that don't reach full power w/o the bass control knob plugged in. Bad design IMO, as I do the majority of systems without using the remote sub level knob..

 

[psych0ticnemes1 5,000+ posts]

Do you know if some Hifonics amps need the bass knob in order for the level to be set correctly?

 

[DNick454 10+ year member]

Just send another power wire from the battery to the amp and wire in an interrupter switch and mount it on the dash. You can then just turn the amp(s) on at will.