dan83590

The sound has stopped from my sub. How do I test to see what is at fault?

It started to cut out a few months back and now it gone altogether. I dont know if it the amp, head unit, or sub. I dont have spares to plug in either.

The amp lights come on with the ignition so it has power. Also a similar thing has already happened where my old amp was cutting, then it died, I replaced the amp with this one. The head unit and sub remain the same.

RE54

iTrader: (6)

general fault finding...

swap the sub with a known working speaker or sub? just test it quietly...that will tell you if the sub is getting signal?

if you put a new speaker in and it works, then its the sub gone. if you put it in and it doesnt work, then its either the amp or the wiring...that should be a good simple start point.

dan83590

Okay. I'll try one of the house speakers to see what's what.

Could the speaker damage the amps in any way other than poorly matched gear?

RE54

iTrader: (6)

no, just keep the volume low...house speakers run on different ohm...it wont matter as long as its quiet.

so try those, it should tell you if its the amp/speaker/head unit.

if the amp light turns on, it would normally rule that out, so im going to guess its an RCA cable or the sub itself

dan83590

Could using thin speaker wire on this set up have done the damage?

snake1906

iTrader: (4)

thin wire wont cause damage but it wont work well its more than likely the rca cables as said above,they usually fail around the plugs

shanew

If you've not sorted this out yet.
Fault finding is pretty simple. For the sub, remove the speaker cable from the amp. connect one end to 12V and briefly touch the other end to earth. this should cause the cone to move either in or out depending on which way round the wire are connected, if it moves it works, if not then chances are the gain was too high on the amp and when it was cutting out it was the amp going into protect mode and now the voice coil on the sub has gone.

If the subs fine, move on to the amp. remove the RCA's and switch on the head unit. see if you have any lights. for some reason the small amount of current from the rca's is enough to back feed through the amp and light the power led on most amps.

If you have no lights then check fuses. if these are ok then check the ground is clean and secure. if this passes, remove the remote turn on wire and use a small piece to connect the remove to the 12v on the amp. this will eliminate headunit issues.

Idealy get yourself a multmeter. select dc for checking power connections and ac for rca signal and speaker output and finaly the Ohm setting for checking the speaker.

dan83590

I finally got around to doing this. The speaker moves in and out when connected to a battery. The remote wire does signal the amp to turn on. As soon as the amp is on it goes into protect mode. I have tried moving the speaker wires to the other terminals, bridged and unbrigded and amp goes to protect mode again. I have tried different RCA leads, same thing happens.

I've not used a meter on anything yet though.

Is it the amp again?

alcazar

iTrader: (2)

You checked the speaker resistance?

dan83590

No mate. I'm collecting a electrical tester in the morning though. What do I need to do with it?

chrisl25lnf

hi mate r u anywhere near derby i can take a look for you .cheers chris

dan83590

Nowhere near matey..

Okay, I have a multimeter.

Power connection check, I can do that.

RCA and Speaker wire, what am I looking for? I assume once AC is selected I am looking for a variable voltage?

And finally the speaker, select Ohm and then what? Do I just touch each terminal with the speaker disconnected? What should I see?

Mollymoo666

iTrader: (1)

If you disconnect everything from the amp except power and earth does it still go into protect?

dan83590

I had power, earth, remote connected. Speaker wires connected. NO rca's connected. It went to protect mode.

Mollymoo666

iTrader: (1)

Disconnect the speaker cables and try again

dan83590

Will do. What will this prove?

Mollymoo666

iTrader: (1)

The most likely cause of a protect when the amp is still powered is a damaged cable breaking or earthing the circuit. This often happens in the speaker cable. If the Amp still protects with no signal or outputs connected then it is a case of routing temporary earth, power and remote cables as a process of elimination. If after all that the Amp still protects then the Amp is probably a goner

dan83590

Thanks. Will try that out.

snake1906

iTrader: (4)

to follow on from above you can iliminate the remote by disconecting and bridging across fromthe permanant live,but as im writing this if its not the rca/speaker cables doing this then its your amp

dan83590

Dead

Thats the second amp I've been through on that sub. I'm not hard on my kit either!

Do you reckon its bad luck or something else?

Mollymoo666

iTrader: (1)

something else, amps rarely fail unless something has fried them. First guess would be a wiring fault, second guess would me mismatched equipment

dan83590

The sub is 360RMS. Amp number 1 was mismatched and I wasn't surprised when it died, it was very cheap and too small. The second amp was a vibe amp bridged which was 300RMS. This latest amp is bridged at 200RMS. Speaker is 4ohms, when tested its actually 4.3ohms.

The wiring is sound but may be a little small, TBH I don't know if it is okay or not.

Mollymoo666

iTrader: (1)

Right, could you please do a wiring diagram of your set-up, as detailed as possible (in MS Paint is fine) including make and model of all equipment, cable gauge if known, where cables are routed and connected, amp settings, fuse ratings, fuse locations.

Could you also confirm that you have checked every inch of every cable and they are all undamaged? Does the power cable go through a grommet as it passes through the bulkhead?