JL 500/1 Input Sensitivity Setting-Low output voltage

[gsxtasy]

Alright, so I have this JL 500/1, and I just put in a new 8w7 and hooked it all up and it was pretty quiet, so I went to adjust the input sensitivity as described by the manual.

So I get it all setup, and even with the gain all the way clockwise, while running a 50hz sine tone, I am still only getting around 5.5v on the sub output terminals. It's supposed to be up to 38.7v for a 3 ohm sub.

I don't know too much about this stuff, so does anybody know is this a problem with the amp/amp settings, or headunit problem, or bad RCA's?

I'm using an Alpine CDE-126BT headunit.

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[Why So Cereal? 5,000+ posts]

change your input (high/ low switch)

 

[gsxtasy]

change your input (high/ low switch)

I had the 'input voltage switch' set to low, as the manual recommends. I also tried it on high and it makes the voltage even lower.

 

[>>SQL<< 10+ year member]

you did have the DMM on A/C voltage, right?

 

[gsxtasy]

Yes sir.

 

[nauc 10+ year member]

double check the xovers on the deck and the amp. make sure theyre on lowpass, not highpass. also check the amp ground and turn up the sub volume on the deck if it has one

 

[gsxtasy]

After some help and more diagnosing, it appears to be a head unit issue. It is not providing enough voltage to the pre-outs. With a 50hz sine wave playing at 80% volume I am only getting around 100mV to the sub outs on the head unit.... I am unsure why, as this head unit is only a few months old.

 

[>>SQL<< 10+ year member]

Well if you do not want to change out your headunit you could use a LOC hooked into the speaker outputs from the headunit

 

[audioholic 5,000+ posts]

After some help and more diagnosing, it appears to be a head unit issue. It is not providing enough voltage to the pre-outs. With a 50hz sine wave playing at 80% volume I am only getting around 100mV to the sub outs on the head unit.... I am unsure why, as this head unit is only a few months old.

Some models of h/u's require the bass function to be turned all the way up before the h/u will output advertised signal voltage.

 

[vaiboy 10+ year member]

There are two subwoofer settings on that head unit that could cause the problem.

SW ON/OFF should be set to SW ON

SUBWOOFER Should be set to +15

 

[gsxtasy]

I had the subwoofer ON, and the subwoofer at +12 when doing this test. I'm almost positive the pre out driver in the headunit got fried from a pinched RCA or something like that.

 

[Greggk 10+ year member]

Off topic but how do you like the Alpine CDE-126BT?