Amp Problems

Tom Messy

Tom Messy

Ex. Club Member
This only started yesterday (had the amp a week), but it keeps turning itself off every so often.

Today on my way home from work it switched off after about 10 mins @ 2/3 volume. I had to turn it off and on again to make it work. Since then, it got more and more frequent as I drove home, and I had turned it down as well.

Is there an obvious problem? Bad earth? Bad remote turn on?

Any help would be great.

Tom
 
If your turning it off and on, it would probably suggest the wiring is fine (as the instruction to turn it off and on is ok), maybe it's over heating or is some other safety cut out. Which Amp do you have and how have you wired it up?
 
Thanks for replying,

I have the Fli 900s, switched to two channel (4 channel seems to require another lead from the head unit). I have 4 cheap Alpine 6.5" speakers running off it, one from each of the amp's outputs. I've also set it to high pass only, as the speakers weren't coping with any bass when set to "full". The sub can do that for now.

The remote turn on is combined with that of my Fli Trap 12 sub, with a little switch in the center console.

It's almost as if I have just switched it off, but the sub is still working fine which I suppose rules out the remote turn on.

Tom
 
Tom Messy said:
Thanks for replying,

I have the Fli 900s, switched to two channel (4 channel seems to require another lead from the head unit). I have 4 cheap Alpine 6.5" speakers running off it, one from each of the amp's outputs. I've also set it to high pass only, as the speakers weren't coping with any bass when set to "full". The sub can do that for now.

The remote turn on is combined with that of my Fli Trap 12 sub, with a little switch in the center console.

It's almost as if I have just switched it off, but the sub is still working fine which I suppose rules out the remote turn on.

Tom
Click to expand...

I would need pictures to confirm this but if the amp is 'switching off' it maybe down to the following.

1. You are connecting two 4 ohm speakers in parallel so your amp is seeing a load of 2 ohms. As the amp is not 2 ohm stable it is most likely going into protection mode to stop any damage from occuring.

To resolve this you must;
1. Get two Y splitters for the RCA cables or buy a different headunit with 3 pre-out's
2. Connect one speaker per amplification channel.

In the mean time
Remove one set of speakers from the amp
 
Thanks Mike. My head unit has 3 pre-outs, so if I just get another RCA (?) cable from the head unit to the amp and switch it to 4 channel, it should solve the problem?

Tom
 
The pre-out should be labelled as front, rear and sub. Attached the RCA's and speakers accordingly, this should hopefully solve the problem.

Also don't continue driving with the amp as is, either no music or just one set of speaker unless you want more damage to your amp.

Mike
 
The amp should be 2ohm stable Mike.

How exactly are you wiring your speakers to the amp Tom, just 4 speakers wired in to each of the 4 output channels?

Then you just have a 2-channel input, so feeding 2-channels into 4 outputs yes? That 'shouldnt' actually cause any problems, you may just be pushing the amp too hard.

What are the amp gains set to?

Edit: But yes, just buy another RCA and run in 4-channel mode if you can.
 
must of pulled up the wrong amp spec's earlier, the amp is 2 ohm stable in stereo mode. So it's what pete said
 
Maybe amp fuse? I put a bigger fuse in when mine blew and when I turned volume up use to turn it off all time.so I put a smaller fuse In and It worked fine
 
Retepetsir - Yes, one speaker per output in two channel mode. The gain on channels 1 and 2 (all speakers) is set between 1/3 and 1/2.

ollyc98 - That would be brilliant if you'd be able to send them. Let me know what postage will be and I'll send you the money.

Tom
 
I got the RCAs this morning Olly, thanks for that. They do look like pretty good quality ones :)

I've wired it all up now, but now I'm getting interference from something, and I wasn't before. It's not the new leads I don't think, as I haven't run them near any power cables that I know of. They are going down the right hand side of the car under the carpet. The other RCA runs down the left, and is close to the amp and sub power cables but I haven't had any problems in the past.

The sound does stop when I unplug the black lead of the new RCA from the amp, and also if I unplug red lead of the old RCA.

All 4 speakers get this interference if that makes and difference.

Any ideas?

Tom
 
Wow that was quick, I only sent them yesterday lunchtime.

I had this problem on a 4 channel amp, I removed the ground on the left rca and it solved the problem, maybe someone has a more technical solution

Try swapping left/ right around on one set of rca's, and is the amp in bridged mode?
 
OK thanks for all the tips. I've sorted the majority of the interference by re-running the cables at the amp end, but now it only comes on when the engine is on. It's fine with the ignition, just the engine. Does this narrow it down at all?
 
So if you turn your stereo on when the engine is off then the amp doesn't work? what power cable are you using? It might be too small. Upgrade to 4 gauge, I may well have some 4 gauge if you need it
 
No it works, I just get interference when the engine is on. I used to get worse interference when only the ignition was on as well.

Tom
 
Oh that's an easy one then, your earth is bad, use one of the seatbelt points.

Also are your RCA's going to your headunit or do you have those resistor things on your speaker outputs>?
 
I earthed mine on my boot catch cos I just couldn't be bothered, with the low pass filter on you can't hear any alternater whine at all
 
I did have it with most of my other earths on the bolt in the boot just below the right hand light. It's now on the boot catch, and it's still a similar problem. Will try the seat when I have time.

Cheers,

Tom
 
I don't think this particular buzz is due to a bad ground now. I sanded down to the metal under the boot catch and have it wired to that, but still a buzz :( I don't know what to think now. Could it be that it's interference from behind the headunit/dash? If so, is there a way of insulating the speaker cable/RCAs?

Tom
 
Amp Problem

Hey People

I have just recently purchased an entry level subwoofer and amp
a little 10" SPLX Sub with a Sub Zero 400w Amp
after following all required instructions. my amp still won't power up
I've checked all the cables and they go where required
This has baffled me
after reading my head units instructions i made sure everything was in the right place, but still its not having any of it
its a K11 97reg Micra
the head unit is a Kenwood KDC 3027A
If anyone could help it would be immensly appreciated
Gav
 
Got my amp and sub wired into my car
but no power to it
not sure if i've blown the fuses or not
i have it wired into battery and its grounded to the bolt on right hand side of boot
i'm thinking it's remote cable to head unit
i have put it into the blue/w white cable and still doesn't power up. is there anything else i can do??
 
Hey all :) managed to get my amp and sub fired up
ended up having to bridge it from the 12v power to the remote power on the amp. putting a switch in the middle to turn it on and off :)
 

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