Troubleshooting Sub/Amp Installation Problem

[phuphyter]

Car: 2004 Toyota Matrix XRSStock head unitOld 2-channel Kenwood Amp (Don't know what model right now)Two 10's each with a set of +/- terminals mounted on the box. They're inside a ported box, so I can't tell what brand/ voice coil configuration they are without dismantling it. All I know is that the amp and the subs came in set together, so it's safe to assume they are compatible.

I just helped my friend wire the amp and a line-out converter. The LOC was spliced into the rear speaker channels, the amp was wired to the battery, rca's hooked up to the amp, and the amp to the speakers. Each channel the 2-channel amp was connected to one +/- on the box. Everything looked to be installed correctly.

When it came to test it out, we hooked up the negative terminal back to the battery and turned the key to Acc. and played a CD. The amp lit up, so we knew it was getting power, but no sound coming from the subs. We tried fading all the sound to the rear, still nothing but sound coming from the rear speakers. I messed with the gain - nothing, low pass frequency - nothing, stereo or mono setting - nothing, tried every combination of rca input - nothing. I checked the fuses and they were fine.

I was thinking it was either the ground or the remote turn on lead, so I decided to test out my Infinity Basslink. I ripped it from my car and hooked everything up to his and it worked perfectly. Power, remote turn on, and ground were obviously not the issue, so I took an AA battery and tested to see if the subs would pop if I connected it to the positive and negative wires, and they both did. Isn't that a correct way of testing if the subs are operational?

I'm thinking it's just the amp, but I don't really know that much about these things. I have a multimeter, but I don't know how to use it and I'm afraid of electrocution haha.

Maybe the subs have to be wired in series or parallel and the amp set to mono... But with the subs inside the box, I can't determine neither the voice coil config, nor the impedence.

Sorry I don't have pics right now, but any input would be greatly appreciated. Thanks.

[Looneybomber]

Ok, try this. Take you LOC off, go from speaker level outputs, wire your RCA pigtails to it and hook it up the inputs on your amp. Now here is the important part, TURN YOUR RADIO'S VOLUME ALL THE WAY DOWN!!!! Set the gain on your amp at 15-25%. Turn the radio up from vol 0 to vol 1, do you hear anything from your subs? If not, turn up the radio to vol2, then turn your gains on your amp up.

If for some reason you're still not getting any sound, hook up your DMM to the + and - of your left or right channel comming from the headunit, not the amp and select AC volts. Are you reading anything, if so how many volts? Keep the leads hooked up to the wire and turn your headunit up some more, but do not let the voltage go past 3volts! Before turning your headunit up, turn your amps gain back down to 15-25% just incase.

If you send the amp a 3v signal with the gain turned all the way up and still hear nothing, you have a bad amp.

If you heard sound right away, then you know your LOC are not what you need. You'll then have to look around for something else. Good luck.

[phuphyter]

Last night we swapped the amp for another one and it worked! We knew the LOC and wiring was correct since my Basslink worked. Nothing was changed except the amp, so I'm guessing something's fried.

He was going to throw away the old kenwood, so I kept it. I'll try testing it on my frontstage speakers using your troubleshooting guide and see how it goes.

Thanks for the help!