No output from Amp when hooked up to car, fine when on seperate power supply?

[yamahondarider]

Hey guys, I've got a strange problem that i can't figure out. I've got a Sony Xplode 500W Amp, and I am running the positive straight to the battery (25A inline fuse), and ground straight to the battery, and the trigger wire is coming from the power antenna activator wire off my head unit. I am using an RCA cable from the back subwoofer output on the head unit to the input on the amp. If I have the amp wired up to to the car as described, it comes on just fine when I turn on the ignition and radio, and the green power light is on, but nothing. no sound? Now, If I use my home made power supply (computer power supply) wired up to power and trigger the amp, and then turn on the head unit (still powered by car battery), and have the RCA cables set up the same, it outputs to the subs just fine. What is going on there? Any advice? Thanks.

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[plugitin 5,000+ posts]

Hey guys, I've got a strange problem that i can't figure out. I've got a Sony Xplode 500W Amp, and I am running the positive straight to the battery (25A inline fuse), and ground straight to the battery, and the trigger wire is coming from the power antenna activator wire off my head unit. I am using an RCA cable from the back subwoofer output on the head unit to the input on the amp. If I have the amp wired up to to the car as described, it comes on just fine when I turn on the ignition and radio, and the green power light is on, but nothing. no sound? Now, If I use my home made power supply (computer power supply) wired up to power and trigger the amp, and then turn on the head unit (still powered by car battery), and have the RCA cables set up the same, it outputs to the subs just fine. What is going on there? Any advice? Thanks.

It's called a remote power wire. Seems to me your electric antennae wire isnt cutting the cheese. I'm willing to bet that the power antennae output from the HU only has voltage for a short period of time. You can test this by jumping from the main power wire input on your amp to the remote power wire input on the amplifier. If it works, then you know its the input voltage from the HU that is not working

 

[yamahondarider]

It's called a remote power wire. Seems to me your electric antennae wire isnt cutting the cheese. I'm willing to bet that the power antennae output from the HU only has voltage for a short period of time. You can test this by jumping from the main power wire input on your amp to the remote power wire input on the amplifier. If it works, then you know its the input voltage from the HU that is not working

Alright I'll give that a shot tomorrow. But, the green power light on the Amp stays on the whole time and doesn't go out, and I think I remember the wire on the head unit being identified as Antenna or Amp trigger?

 

[gckless 5,000+ posts]

The power antennae wire normally will do one of two things:

1. Will only provide power when the car is first started to activate the antennae, and then again to retract the antennae when it's turned off.

2. Will provide power only when "Tuner" is selected on the HU.

But you saying that the amp goes on and stays on suggests the remote wire may not be the issue. The amp would be turning off if that was the case. To test, you can run a jumper from your main power wire to the remote wire.

 

[yamahondarider]

The power antennae wire normally will do one of two things:
1. Will only provide power when the car is first started to activate the antennae, and then again to retract the antennae when it's turned off.

2. Will provide power only when "Tuner" is selected on the HU.

But you saying that the amp goes on and stays on suggests the remote wire may not be the issue. The amp would be turning off if that was the case. To test, you can run a jumper from your main power wire to the remote wire.

If that doesnt work then I'll hook up the trigger wire from my home made power supply to the Amp, just for trigger. If it works, I know the trigger wire off the head unit isn't doing its job properly.

 

[gckless 5,000+ posts]

If that doesnt work then I'll hook up the trigger wire from my home made power supply to the Amp, just for trigger. If it works, I know the trigger wire off the head unit isn't doing its job properly.

Well you are using the power antennae as your remote wire. Does your HU have a remote wire? If so, you should be using that. Also, you can measure your power antennae and see what voltage it's giving you. If you don't have a remote wire, and your antennae wire is giving you crap power, then you could run a hot wire to a switch and then just turn it on whenever. There's almost definitely another way that I can't think of right now though.

 

[yamahondarider]

UPDATE!

Went out and messed with it a little more. Had a for-sure working trigger wire, the amp was on, and I had the power and ground hooked to the car battery. Trigger was from my home made power supply. I used a RCA to headphone cable that I've used many times before for input, and still nothing. Head unit isn't the issue. I replaced the 7.5 amp in line fuse on the power wire with a 30 amp fuse. The amp itself has two 25 watt fuses. All fuses are good. Still, no sound when hooked up to a battery? The battery is good, BTW....

 

[mlstrass 5,000+ posts]

have you tested for 12v at the amp? Start there and you can just use a jumper wire from POS on amp to REM, don't need to use your home made power supply...

 

[plugitin 5,000+ posts]

and that sony amp is far from quality...so that very much could be the problem