Sub broken?? Or is it the Amp? What's going on?

[jazza15]

So I've been having a problem where the rear parcel shelf speakers and the Sub randmomly cuts in and out (doesn't seem to have anything to do with frquency).

I bought my car with this system already installed. It has tweeters, all door splits, the parcel shelf speakers and the Sub all upgraded/installed. All running through the amp. So i don't know a whole lot on the matter.

So checked the wiring and it seems fine. Today I disconnected the Sub and the rear parcel shelf speakers no longer randomly cut out (and back in again).

So my question is what's going on there. Does the problem lie in my sub? They are usually working or blown (not working) aren't they. Is it the amp? Settings?
I switched it (the amp) to 'full' after d/c the sub and testing, which didn't really seem to make a difference but the guy (who wired it up) i bought it (the whole car) off said to do that if i was gunna d/c the sub.

[holdenboy]

So let me get this straight...youve got the front speakers (splits), rear speakers and subwoofer running off the amp?

Could you provide the model number / brand of the amp? Unless its a 5 channel amplifier then the amp has been wired up wrong. You cannot run 5 speakers (be it speakers or subwoofers) off an amp that has only 4 output channels. Hence the reason why when you disconnect the subwoofer the speakers work fine, by the sounds of it your amp is going in and out of protection.

You have a few options here......you could disconnect the subwoofer altogether and just keep the fronts and rears connected, disconnect the rear speakers and "bridge" the rear channels to run the sub and run the rear speakers off the head-unit. Your only other option is to buy another amplifier / wiring kit and use this to run your subwoofer.....leaving the other amp to run your speakers.

[jazza15]

OK, so I went an had a decent look at what wires were going into and out of the amp.
The amp has the rear parcel shelf and (had) the sub speakers running out of it. Which means the tweeters, front splits and rear splits are running from the head unit.
Previous owner did mention that protection mode, showed me how it works by progressivly turning the stereo up until the speakers cut out. However this problem started occuring this year. I got the car early last year. It happens regardless of volume.
Some details of setup:
Amp is a Power Acoustik (PA 400)
Rear parcel shelf speakers are Sherwood 6X9's 160W, 4 ohm's Impedence
Sub is a Cobolt 400W

[holdenboy]

The protection mode shouldnt just "come on" at a certain volume level....its there to protect the amplifier from killing itself.
The amp has definately been wired up wrong (too many speakers running off it), and has more than likely caused damage to the amp or protection circuit over that period of time.

If the amp works fine with just the four speakers connected (not the sub) then leave it like that.....or do as i said in my first post.

[stated vr v6]

Protection mode should not come on till ya have it cranked up or in really bad heat, other from that it is wired up wrong just like holdenboy sez

[holdenboy]

Protection mode should not come AT ALL, unless you have a major problem, regardless of the volume level......the speakers should distort badly before protection kicks in.

[jazza15]

So i have looke dinto the problem more. Pre-tinned the sub wires just in case they were going a bit dodgy.
I think it's a 4 channel amp (PA 400), with the rear parcel shelf 6 x 9's bridged? across 1 & 2 and the sub across 3 & 4.
Now aross to the other side of the amp and, this is were i did all the fiddling.
I currently have the sub crossover on 'low' (as opposed to 'full' or high') and the rears on 'full'. Now both have a min to max knob, with the rears being at min and i think heres the problem, the sub not being able to operate much past min.
Now originally, (or unless i fiddled with this knob, not noticing what I've done andf then 'why do I have a problem?') the sub crossover knob thing was set at about half way between min and max, which was a good level for it, otherwise the rear speakers overpower it, volume wise.
Now for the amp to operate without the power light turning off (cutting out) i have ther knob turned to about half of what it used to be at (half way round). I'm sure on a song with some 'kicking bass' it could be even less, but didn't have time to be changing music. If it cuts out, it is at the low frequencies that the sub uses, bot the full/higher freq's that the rears use.
So what is wrong?
I have read all of your responses, a lot being 'it's wired up wrong' but I previously never had this problem before. Haven't fiddled with the wiring up until now and I'm sure i put it all back the way it was.

[holdenboy]

Do you have the front speakers running off the amp, or is it just the 6x9s and the subwoofer?
Might be an idea to take a photo of the amp wiring and point out which wires go where.
Also in the pic get the size of the wiring cable used for power/earth.

In all honesty mate the gear your using isnt the best of quality, which may be half the reason why your having troubles.

But just take a pic of the amp wiring and get back to me. Filters and gain settings a irrelevant at the moment untill i can verify that the wiring on the amp is up to scratch.

[Jaso88]

if the wiring wasn't write than bits and peices wouldnt work at all
electricity flows if it can and doesnt if it can't
i'd lean towards dodgy connections possibly causing too much resistance in the circuit
or the amp is just getting too hot, whether it be from use or positioning

[camstatic]

Just something worth checking into:

A lot of older/cheaper woofers have a problem where if you use them aggressively, over time the tinsel leads:
can wander away from their usual position, and begin to earth out on the frame of the woofer at higher volumes, forcing even the most solid amplifier into dc protect mode or worse.

Definitely worth checking in to.

6x9s running off of channel 1/2 would be fine on 'high' filter, sub bridged on 3/4 running on 'low' filter, then adjust gains accordingly.

Good luck.

[holdenboy]

By wrong wiring i mean too many speakers running off the amp (too low impedance). This can be fine if you dont turn the volume up past a certain level....but after that the amp tries to pull more current than its capable of and trips into protect.
Also going with the low impedance theory, using power cable thats too small for the amp will result in a lower voltage at the amps' terminals, which will also cause the amp to go into protect.

So basically, yes if the wiring isnt right then components can work sometimes, and sometimes not. Going off his explaination it sounds like a wiring / configuration problem more than components. Yeah sure they do come into it as a possibility but im thinking more towards my first thought.

The OP also wrote in his first post that his front speakers (splits), rear speakers (6x9s) and subwoofer were all running off the amplifier.

[jazza15]

I'll try and get that picture tomorrow.
And just to confirm it is the rear parcel shelf 6 x 9's running off channel 1/2 and the sub off 3/4, that's it.
Inspected the wiring on the sub and it appears to be fine.
It's clearly not the best gear, but i've got no complaints when it's working, nor am I looking to upgrade as I don't have the money, nor do I want to be putting my money into car audio, it's a trap.
So hopefully I don't learn much in the process of getting this to work again and not get tempted into upgrading my system... too much ...oh no!

[holdenboy]

lol.

So the amp is working fine now youve only got the 6x9s and sub connected?

[jazza15]

Yeah it did when I had only the 6x9's connected.
Hooked up the sub and it only works when i have it turned right down to a dis-proportionate level. Not as loud as it used to be. Will try and get the photo's soon, but until then I am open to any suggestions/ideas.

[jazza15]

Ok, so here are the photo's of the Amp setup.
The thick wires go to the sub (channels 3 & 4) and the thin wires go to the 6x9's (channels 1 & 2) the rest I'm sure is self explanitory in terms of power cord etc.

In the second photo is the x over. The knob on the left, near the power light controls the 6x9's, it is turned down to min as that is all that's necessary for a good balance.
The problem is on the right hand side, where you may be able to see that it is only turned up about a quarter of the way as that is about as far as it will go without cutting out during deep bass. Fiddling with the High|Full|Low on either side had no real effect on fixing it (cutting out).

[holdenboy]

Ok then....well by the looks of that the amp is wired fine. Proper gauge power/earth cables are used and the speaker wiring looks fine. On the other end everything looks OK too.

Seeing as the amp has been wired wrong in the past (running the fronts, rears and subwoofer) i would imagine it has done some permanent damage internally.

Try wiring the subwoofer off just channel 3 or 4 (not bridged) and see if it stops cutting out......even try hooking up the sub by itself not bridged. If the problem persists and its only happening when youve got the subwoofer connected then i would be turning my attention towards the subwoofer itself.

Another thing to do is grab/buy a multimeter (can be had for $10 at SCA) and while the system is on and playing music (car on/off dosent matter at this stage) check the voltage on the amps terminals.

Its really hard to diagnose / rectify problems like this over the net, i can go over probably 10 different things to check, including individual speakers, RCAs, connections etc etc.

[jazza15]

Ahk thanks for that.
Just a note: the fronts were never hooked up to the amp (to my knowledge).
I'll try what you said and let ya's know how it went.

[holdenboy]

Ohh, well ok....if the fronts were never amped then as far as wiring configs. go then it should be fine.

Im starting to lean more towards component error (either speaker/s or amp). Try hooking just one speaker up at a time and turning the volume up......if its a speaker then you'll find that out soon enough. If it still goes into protect after youve tried all speakers then its possible the amp is faulty.

[jazza15]

Ok, so i de-bridged the sub (previously across 3 & 4) and hooked it up to just 4. Got nothing coming from the sub.
So i tried it on 3 and it worked perfectly fine, was able to adjust the level without any cutouts whatsoever.
So it is working well now, but what's going on. what has gone wrong so that i can't bridge the sub across 3 & 4? or even hook it up to just 4?
Anyone know why?

[holdenboy]

I'd say theres a problem with channel 4 somewhere.....could be internally or the RCA input. try swapping the RCAs around on ch. 3 and 4.

[jazza15]

Ok, thought i'd revisit this issue now that it is a little longer down the track.
Now channel 3 is starting to cut out the sub, but not very often.
Now my car is mostly parked outside, in the sun (yay), so I am starting to think that if I buy another amp, the heat could still cause problems for this aftermarket component.
Rememebr that this is currently a pov pack amp (power acoustik). Will upgrading to a brand name ie. kenwood, pioneer etc. solve this problem permanently, or will the heat from my boot cause it in my next amp?

[holdenboy]

Different amps have different protection circuits, and when protection kicks in. I would say this has something to do with the limits of the amp (be it current or heat).

So, yeah, basically a decent name-brand amp *should* be fine with your car.....afterall they are designed to be mounted in cars and i assume the designers realise cars get pretty hot