Low level input not functioning properly?

[jmj 10+ year member]

I have an Alpine MRP T220, which I have bridged to run a 10" shallow mount sub in a custom box. I would like to use it with an active crossover, but it appears that the low level inputs are not functioning, i.e. when I wire up a LOC from my stock head unit I get no output to the sub.

Is there a good way to test the inputs? I'm currently using the high level inputs and no crossover.

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[benzmansl65amg 10+ year member]

I have an Alpine MRP T220, which I have bridged to run a 10" shallow mount sub in a custom box. I would like to use it with an active crossover, but it appears that the low level inputs are not functioning, i.e. when I wire up a LOC from my stock head unit I get no output to the sub.
Is there a good way to test the inputs? I'm currently using the high level inputs and no crossover.

Take an iPod or phone or cd player anything with a 3.5mm headphone jack. Get a cable that goes 3.5mm to stereo RCA (red and white) and see if it will play that way if not. Then your amp is done. If it will then its either your rcas your LOC or your wiring.

hope this helps,

Joe

 

[jmj 10+ year member]

Thanks for the reply, Joe. I happen to have one of those cables, so I'll give it a shot. I assume I could continue using the speaker level inputs if it turns out the low level input is toast?

 

[LiveAudio911 10+ year member]

Damn good advise...

 

[jmj 10+ year member]

So I unplugged the high level harness, switched the amp to full pass, plugged in my wife's iPod with a mini jack to RCA cable, and it worked. The only variables are 1. the LOC (it was a Scosche LOC 80 2 channel) or perhaps 2. the switch on the amp? The LOC was connected to the same wires as the high level harness is now. Tried connecting a standard RCA cable using both channels of the LOC, then just one channel using a Y-adaptor. Neither seemed to work.

 

[jmj 10+ year member]

After I posted last it occurred to me that I should check to see if the amp works with the iPod plugged in and the amp switched to low pass, and it does. Since it works with the high level inputs, should I assume the LOC is the culprit?

 

[Horsemanwill 10+ year member]

yes