No sound, clueless.

[Scotty D]

Hi all, finally got my ass around to putting a “system” in to my truck. Let me start by saying this is my FIRST time installing a system so go easy on me. So the problem is I’m getting basically zero out put/sound from my sub. I started out with a kenwood KDC-MP205 head unit. A Pyramid America PB2600 (got free) and a MTX 8” Sub not sure on the wattage. So I hooked it all up exactly like the wiring diagram called for, all new wiring that came in the wiring kit.

The red light on the amp came on (probably why it was free)

Good 12v power cable hooked directly to the battery(tested with a test light and DMM).

Blue “rem” wire turns on with ignition and puts out 12v like it’s supposed to.

Good ground mounting, actually tried multiple spots.

Tested the sub and get 4 ohms

Tested RCA cables and multiple sets
Couldn’t get it to work.
So I bought another head unit (kenwood KDC-135) and then a clarion APX400.2 amp.
Hooked it all up and still nothing. Green light is on on the amp, sub settings on the head unit turned all the way up. Only 2 plugs on the back of the head unit and amp. I have an adapter to plug a 3.5mm jack into my phone with a RCA on the other end of the adapter, plugged it into the amp and still nothing while music is playing on my phone.
I apologize for the extremely long thread lol but I can’t figure this out.
I have tested the sub with another power source and it works fine.
Only thing I can think of is that the amp, even with the green light on is actually junk. Again, sorry for the long ass thread I just didn’t want to leave out any details. Thanks!

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[Graves]

For starters you could use your DMM on AC volts and let us know what the RCA volts and amp voltage across the speaker terminals for more information.


If you don't have any voltage coming from the RCA's check your deck's settings if it has an option, like mine does, to turn off subwoofer etc.

 

[Popwarhomie 5,000+ posts]

May be a stupid question but did you set the gains on the amp?

 

[Scotty D]

Gains set at about 50% and RCAs put out 0.00 on my DMM. On my HU I have the subwoofer adjuster turned up all the way also. I did the test with the rca’s plugged into the HU, sub adjustment all the way up and the volume at like 60%. Then probing the opposite end. I used my DMM to test the rca out puts on the deck and those seemed good. The ONLY noise I get from it is so faint that your ear must be right on the speaker to even notice it. I’m not an expert on this stuff but like everything there is ALWAYS a reason, I just haven’t figured it out yet. I really appreciate the responses!

 

[Jeffdachef 5,000+ posts]

do the aux phone to RCA splitter test with the new amp. Make sure subsonic filter is all the way down, low pass filter right around 80 to 100. bass boost off.

Make sure you wired the sub right,
make sure the head unit doesnt have a secret sub on and off menu that you havent see yet.
make sure RCAs work.
Make sure speaker wire does not have a cut or short anywhere.

 

[Graves]

Gains set at about 50% and RCAs put out 0.00 on my DMM. On my HU I have the subwoofer adjuster turned up all the way also. I did the test with the rca’s plugged into the HU, sub adjustment all the way up and the volume at like 60%. Then probing the opposite end. I used my DMM to test the rca out puts on the deck and those seemed good. The ONLY noise I get from it is so faint that your ear must be right on the speaker to even notice it. I’m not an expert on this stuff but like everything there is ALWAYS a reason, I just haven’t figured it out yet. I really appreciate the responses!

so gain doesn’t matter when checking the RCA’s, we want to do an AC voltage check on the RCA ‘s when you unplug them from the amp, maybe with a test tone playing (at least something playing) the. If you get a zero reading there then check the back of the head head unit, you should be seeing AC voltage not 0.00.

 

[Scotty D]

So I tapped into my rear speaker wires. Cut a rca cable open and connected the wires then to my amp, radio cranked all the way up so there was plenty of power going to that specific speaker while the rest were shut off. Played with every adjustment, both rca ports on the amp, both left, right and bridged speaker wire out outs. The most I could get out of the speaker (for sure works) was just a whisper that was so quiet I had to put my ear to it to hear.
I then plugged a little Bluetooth type speaker with an aux port into the back of the head unit connected to the rca plugs in the deck, speaker worked great and responded to all the controls and adjustments made on the deck. Basically the Subwoofer and volume controls on it. This leads me to believe the clarion apx400.2 amp I got from the pawn shop is junk even with the green light on. Basically eliminated the deck, speaker, rca’s, and wiring. I put my DMM to AC volts and got 2.0 on both white and red. On the back of the deck.

 

[Graves]

Okay, sounds like you Got it troubleshooted. When every thing is ready to go check that you are still getting ac volts at the ends of the rcas when they are going to be plugged into the deck. It ***** if you got a bad amp from the pawn shop they usually won’t take anything unless it can be verified good, the ones I go to anyway.

if you are going from a high level output from speaker wires they need to go through a line level converter and Not just spliced into rcas. Does the Amp only support RCA input? I’m wondering for further troubleshooting. Scratch that just looked it up that amp has speaker level inputs. Have you tried that? Check the fuse, sometimes partly damaged fuses etc have caused people problems.


id really check out the speaker level inputs before giving up on the amp


also I am curious about a ohm Reading at The speaker wire end before it connects to the amp, measure them disconnected

 

[sicone22]

the only factor that sounds like it as not been changed or checked is the subwoofer. it ohms to 4 you said which means IT should be good but I say push gently and evenly on the sub, does it scratch at all? it should move in and out with no noise and easily...if it does pull the subwoofer out and check the wiring and the tinsel leads.

note on the first amp you said red light is on, this doesnt mean much, does it say protect? a red light can just simply indicate power especially if it is older

 

[sicone22]

if you are going from a high level output from speaker wires they need to go through a line level converter and Not just spliced into rcas.

It should be absolutely however it doesn't need to be to work. I have seen this in other cars I've done installs on. I don't advise this but for trouble shooting it works i suppose

 

[audioholic 5,000+ posts]

It should be absolutely however it doesn't need to be to work. I have seen this in other cars I've done installs on. I don't advise this but for trouble shooting it works i suppose

This is not correct. Amplifiers RCA inputs have a maximum voltage, and a high level signal from speaker wires can easily burn out the input stage of the amplifier. Graves is right, I cringed when I read how he spliced an RCA from his rear speaker wire. Don't ever do this.

 

[Graves]

It should be absolutely however it doesn't need to be to work. I have seen this in other cars I've done installs on. I don't advise this but for trouble shooting it works i suppose

of Course but... he did so with the volume all the way up... and that amp has speaker level imputs.

 

[sicone22]

of Course but... he did so with the volume all the way up... and that amp has speaker level imputs.

True I guess I didn't think that as nothing should be plugged or unplugged while playing and certainly not cranked when first coming on

 

[sicone22]

This is not correct. Amplifiers RCA inputs have a maximum voltage, and a high level signal from speaker wires can easily burn out the input stage of the amplifier. Graves is right, I cringed when I read how he spliced an RCA from his rear speaker wire. Don't ever do this.

I agree you shouldn't however it does work. That's all I was saying.

I don't install ever that way and I will never. I have removed systems that have used that method.

 

[audioholic 5,000+ posts]

It will only work until you turn your volume up to the point you destroy your amplifier's input stage, which would be sooner than you think. There is a reason we have high level and low level input signals.