JL 500/1 Amplifier whine(not alternator whine)

gsxtasy · 19th February 2011, 04:01 PM

Alright, so I just picked up a used JL 500/1 supposedly in working condition, but never verified it.

So I pull out my working alpine amp, and put in the JL, hook it up and the power light illuminates like it is supposed to. However, after it has power for a few seconds there is a high pitched whine coming from the amp itself, and it has no output to the sub. The whine is still there with the RCA's unplugged, and if I unplug/plug the RCA's in, the sub makes a thud. I have the amp set to the 'baseline' settings JL suggests.

This is in a dodge ram with a stock head unit.

I don't know a whole lot about car audio, pretty much just the basics of how things are supposed to be hooked up and work. So I don't really know what to try to fix this or did I get screwed and this amp is just toast? I tried a different ground, same thing. Any ideas? Thank you in advance!

-Aaron

Perry Babin · 19th February 2011, 04:18 PM

With the amp powered up (no RCAs or speakers connected), what is the DC voltage on the positive and negative speaker terminals? Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage.

gsxtasy · 19th February 2011, 04:38 PM

They are both right at 40.3 v.

Perry Babin · 19th February 2011, 06:01 PM

How are you getting signal from the head unit?

gsxtasy · 19th February 2011, 08:59 PM

I'm using a line-out converter.

Perry Babin · 19th February 2011, 09:14 PM

What make/model converter?

gsxtasy · 19th February 2011, 09:28 PM

Had to go double check, it's a Stinger SGN 11.

Perry Babin · 19th February 2011, 10:35 PM

Did you try grounding the brown wire?

If that doesn't allow the amp to produce audio, unplug the RCAs from the amp and measure the DC voltage on the input RCA shields on the amp and on the RCA cables that were plugged into the amp. Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage.

gsxtasy · 11:15 PM

I'm pretty sure it was hooked up to ground through the deck, but I ground it to chassis just now, not sure if it matters, and still no audio.

The actual RCAs read 5.92v, the amp read .593v for red and .618 for black.

Perry Babin · 20th February 2011, 02:57 AM

I think there may be a problem with the converter. It states that it blocks DC but it doesn't appear to be doing so.

19th February 2011, 04:01 PM	#1
gsxtasy diyAudio Member Join Date: Feb 2011	JL 500/1 Amplifier whine(not alternator whine) Alright, so I just picked up a used JL 500/1 supposedly in working condition, but never verified it. So I pull out my working alpine amp, and put in the JL, hook it up and the power light illuminates like it is supposed to. However, after it has power for a few seconds there is a high pitched whine coming from the amp itself, and it has no output to the sub. The whine is still there with the RCA's unplugged, and if I unplug/plug the RCA's in, the sub makes a thud. I have the amp set to the 'baseline' settings JL suggests. This is in a dodge ram with a stock head unit. I don't know a whole lot about car audio, pretty much just the basics of how things are supposed to be hooked up and work. So I don't really know what to try to fix this or did I get screwed and this amp is just toast? I tried a different ground, same thing. Any ideas? Thank you in advance! -Aaron

19th February 2011, 04:18 PM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	With the amp powered up (no RCAs or speakers connected), what is the DC voltage on the positive and negative speaker terminals? Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

19th February 2011, 06:01 PM	#4
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	How are you getting signal from the head unit? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

19th February 2011, 09:14 PM	#6
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	What make/model converter? __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

19th February 2011, 10:35 PM	#8
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	Did you try grounding the brown wire? If that doesn't allow the amp to produce audio, unplug the RCAs from the amp and measure the DC voltage on the input RCA shields on the amp and on the RCA cables that were plugged into the amp. Place the black meter probe on the amplifier's ground terminal. Place the red meter probe on the point where you need to measure the voltage. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links


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19th February 2011, 04:38 PM	#3
gsxtasy diyAudio Member Join Date: Feb 2011	They are both right at 40.3 v.

19th February 2011, 08:59 PM	#5
gsxtasy diyAudio Member Join Date: Feb 2011	I'm using a line-out converter.

19th February 2011, 09:28 PM	#7
gsxtasy diyAudio Member Join Date: Feb 2011	Had to go double check, it's a Stinger SGN 11.

19th February 2011, 11:02 PM	#9
gsxtasy diyAudio Member Join Date: Feb 2011	I'm pretty sure it was hooked up to ground through the deck, but I ground it to chassis just now, not sure if it matters, and still no audio. The actual RCAs read 5.92v, the amp read .593v for red and .618 for black. Last edited by gsxtasy; 19th February 2011 at 11:15 PM.

20th February 2011, 02:57 AM	#10
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	I think there may be a problem with the converter. It states that it blocks DC but it doesn't appear to be doing so. __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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