Sub amp wiring problem

[kjdavis]

Question about wiring my sub amp. Here's what I have...Kenwood DNX-7100 head unit, Phoenix Gold 4 channel amp going to my factory mids for now, and a 2 channel sub amp for 2 JL audio 10w3v2 behind the crew cab back seat.

The amp gets power and turns on, but for some reason I dont get any sound out of the subs. I have the RCA's connected to the sub preouts on the back of the deck to the amp. I have good ground, good power, and good power on the amp power wire from the Kenwood. I have gone through all of the settings on the Kenwood to turn on the sub and adjust anything and everything I can there, but still nothing. I have tested the speakers to see if they are working and they are....no idea whats going on!

I then ditched that sub amp and borrowed one from a buddy to see if it was just the amp. Its a 5 channel MTX thunder series amp, with inputs for sub RCA's and output to the subs specifically....pretty tough to screw up, but still nothing.

Any ideas? Anything to check?

 

[bushpilot]

sounds like you got a bad head unit or one thats not got
a subwoofer pre-amp output.

is there a level set/adjustment on the head unit to control
the pre-amp output <for the sub out?>

damm online manuals are HUGE (5 & 18+ MegaBytes) !

Kenwood - Car Entertainment Owner's Manuals

 

[bushpilot]

see page 94 for SUBWOOFER trouble shooting

are you SURE the subwoofer output it turned ON (page 66)

also the DUAL ZONE needs to be disabled (page 86)

http://inform3.kenwoodusa.com/manuals/DNX7100.pdf

 

[kjdavis]

Yes, the subwoofer output is turned on, and the dual zone is disabled. Tried that several times just to be sure.

Would a bad ground to the amp cause a problem like this? I disconnected the ground on the amp and the light was still on....wondering if the ground may not be good to produce any sound.

This is wierd too...when given power, the subs pull in...staying there....sucking in, if that makes sense...

 

[kjdavis]

I unplugged the RCA's and the subs still remain sucked in...retracted. Not sure how to explain it...

...and the amp is getting REALLY hot. My 4 channel amp is doing just fine...not hot at all.

 

[bushpilot]

I unplugged the RCA's and the subs still remain sucked in...retracted. Not sure how to explain it...

disconnect the wires between the speaker & the amp...whats the
speaker do then ?

 

[kjdavis]

disconnect the wires between the speaker & the amp...whats the
speaker do then ?

Goes back to normal...

 

[bushpilot]

which JL amp do you have (i wanna
set you something...and i wanna make
sure its specific to your amp)

somethings hosed about the wiring
to the subwoofers.

if the amp wasnt GROUNDED it wouldnt turn on.

if the amp wasnt getting a proper
<turn on> signal, you wouldnt get
the green power light.

 

[kjdavis]

I dont have a JL amp...its a MTX 5 channel thats in right now, just using the 5th channel to run the subs to make sure they work. I have the JL 10w3v2 subs.

I disconnected the ground and the light was still on...and its red...not sure if the red is just their power light or if it should be green if its good, red if somethings not right.

 

[bushpilot]

ok sorry i thought you had JL amps too (disregard the part about the colored lights).

disconnect the subwoofer pre-amp input leads @ the amp.
w/ the subs connected what happens ?

what size wire are you using for power & ground ? how long are they ?
check the ground to amp connection w/ an ohm meter confirm that its a
GOOD (bare metal ground).

make sure you have those subs wired properly.

http://mobile.jlaudio.com/graphics/Support/Tutorials/DVC/dvcSP_PP_2.jpg

JL Audio SUPPORT - wiring examples