Got a bit of an issue with my RF T800-4 amp, not exactly sure what I've done to it though.

Long story short had it cranking reasonably hard (nothing out of the ordinary), when it started to cut in and out. The subs (running off rear 2 channels bridged) cut out almost completely. Pulled over to check it out, fuse terminals are glowing orange, and the amp is making a rather odd quiet buzzing noise on the lower frequency hits (basically whenever the subs are going to play).

If I unplug the rear rca's the buzzing is gone and front components play fine, though regardless the fuse is still heating up in a matter of seconds to the point where it will burn you if you touch it for longer than a split second and glowing orange at the terminals.

So I guess my question is (if this is a familiar issue to any of you guru's) have I simply stuffed the fuse, or have I done what I'm dreading which is blown the rear channels?

Cheers guys.

too much michael buble has blown it up due to over gaying such a good amp :P

but srsly, maybe its drawing at the wrong ohmage? (not too sure on the technical terminology)

too much michael buble has blown it up due to over gaying such a good amp :P

but srsly, maybe its drawing at the wrong ohmage? (not too sure on the technical terminology)
Haha I don't really play Buble often, his music is more to appreciate the accuracy of the components :P

The amp is designed to play at 4, 2 and 1 ohm's, so it shouldn't be an issue with that. And it has been playing to the same levels in this setup since last week so I don't see how something like that could have all of a sudden caused an issue, I'd imagine an issue with ohm would be apparent as soon as you turn it on once setup.

Yes but with the rear channels bridged, it will not allow you to wire up your subs @ 1ohm, and probably not 2 ohm either while bridged.

When you heard the buzzing where the subs connected still? What load as you giving the rear bridged channels?

Yes but with the rear channels bridged, it will not allow you to wire up your subs @ 1ohm, and probably not 2 ohm either while bridged.

When you heard the buzzing where the subs connected still? What load as you giving the rear bridged channels?
Rear channels can run 4, 2 or 1ohm bridged. They're running at 2ohm at the moment.

Yeah just had a look, amp can run bridged down to 2ohm. Can only run @ 1ohm in stereo mode.

So that bit seems ok, as I said are the subs connected and running when you hear the buzz?

Majority of amps will run at twice the lowest Ohm when bridged. So your amp is 1ohm stable, when you bridge a channel it will run at twice that, or, 2Ohm.

Here's the specs on your amp:

50x4 RMS @ 4 ohms
100x4 RMS @ 2 ohms
200x4 RMS @ 1 ohm
400x2 RMS @ 2 ohms

As for your fuse running red hot, that means its about to blow. Something is really wrong on the power side of the amp.

Now - whats the size of the fuse? Majority of ANL fuses will require around 5 minutes at 115% of their rating before they actually blow.

What size wire did you wire this up with? 1/0AWG? Is the power wire getting hot?

Is the fuse on the battery getting hot?

Have you checked the amp ground wire?

You can try a simple thing, replace the amp fuse and hope for the best. Short of that, it *could* be a bad ground on the amp thats come loose. However you shouldnt have a low frequency buzz on the rear channels.

This is just a wild guess, but the low frequency buzz could be some capacitors that are fried on the PCB, leaking capcitors can cause a hum/noise.

So that bit seems ok, as I said are the subs connected and running when you hear the buzz?
Correct.


Majority of amps will run at twice the lowest Ohm when bridged. So your amp is 1ohm stable, when you bridge a channel it will run at twice that, or, 2Ohm.

Here's the specs on your amp:

50x4 RMS @ 4 ohms
100x4 RMS @ 2 ohms
200x4 RMS @ 1 ohm
400x2 RMS @ 2 ohms

As for your fuse running red hot, that means its about to blow. Something is really wrong on the power side of the amp.

Now - whats the size of the fuse? Majority of ANL fuses will require around 5 minutes at 115% of their rating before they actually blow.

What size wire did you wire this up with? 1/0AWG? Is the power wire getting hot?

Is the fuse on the battery getting hot?

Have you checked the amp ground wire?

You can try a simple thing, replace the amp fuse and hope for the best. Short of that, it *could* be a bad ground on the amp thats come loose. However you shouldnt have a low frequency buzz on the rear channels.

This is just a wild guess, but the low frequency buzz could be some capacitors that are fried on the PCB, leaking capcitors can cause a hum/noise.
Ah ok no worries. The actual relevant birth figures are 124w RMS x 4 @ 4ohm and 612w rms x 2 @ 2ohm. I haven't checked the battery side fuse, might go check that in a moment. The amp was wired up with 0awg originally, though according to the manual I can use 2awg so for the last week or so since the subs went in (had to move the amp) its been running 2awg power but still a 0awg earth, which I have checked and its perfectly secure.

The low freq. buzz isn't on the rear channels, its actually coming from the amplifier itself when the subs are playing, so basically when the rear channels are outputting.

Got that mixed up (low frequency buzz).

Could be an issue with the Subs themselves, something simple to try.

An easy way to check, disconnect the front speakers. Bridge the front channels and connect that to the sub, swap RCA's obviously.

Check if it makes the sound - if it makes the sound, its a problem with the subs.

If it doesnt, its a problem with the two rear channels.

My bet is on blown voice coils on the subs :ninja:

I reakon if you connect even a full range speaker that you have lieing around to the rear channels it will work without a buzz. That would be the next thing that I would check.

Only other thing as well... do you have a Pioneer headunit?

Plenty of testing you can do to get a cause.

1st: I would test the subs off another amp ( home amp even ) to make sure it's not the coils.
2nd: I would test the RCA's. You can plug in an Ipod with a 3.5mm to 2x RCA into the rear RCA inputs or try running the subs as full range speakers off the front at low volume. If it works on the fronts, could be the signal from the headunit.
3rd: I would put the front RCA's that work into the rear RCA input and run a small speaker off the rear channels in full / defeat / off mode at low volume to test the rear channels.

That should narrow it down a little.

Quite possible.

Sub cutting in and out could be the VC just about toasted......crank it a few more times and really set it on fire :facejump:

Problem solved guys, I don't know the formal term for it but I ****ed the speaker wire between the sub terminals and amp. Replaced it and problem solved, everything is fine again...

..if someone can tell me how a speaker wire sends your amplifier into protect mode and nearly sets the thing on fire with heat build up, I would be very interested to get a valid explanation.... lol

Problem solved guys, I don't know the formal term for it but I ****ed the speaker wire between the sub terminals and amp. Replaced it and problem solved, everything is fine again...

..if someone can tell me how a speaker wire sends your amplifier into protect mode and nearly sets the thing on fire with heat build up, I would be very interested to get a valid explanation.... lol
Internal short is my guess

It wants to run some voice coils, instead all the power has to go somewhere. Amps can tell where something isn't right and will go into protect if it senses something is wrong. This is good, stops fires and the like.

How did you ****** it?

Just out of curiosity :)

How did you ****** it?

Just out of curiosity :)
Took a reasonably tight right hander through an intersection at about 70km/h near full throttle with very low fuel. Caused the car to cut in and out a bit and the amp was stuffing up from there on out. Have absolutely no idea how that cause a problem with the speaker wire!

put petrol in your car and stop listening to michael buble

glad you sorted it out

Progress Update.

Fixed the problem wednesday night as you know, drove for a good 3 hours down to Trav's playing thursday night without any issues. Then, hit a bump coming back on the road which for some reason cut the stereo out. Figured it was a dud earth so tonight I re-did it making sure the connections and all were solid (so I'm running 2awg power, 0awg earth from the amp). Now when I turn the stereo on, at low volume (eg. 10/50) I have no sound, mid volume (25/50) I have crackling sound like I've got no reception (off a USB!) and at high volumes (30+/50) its perfect.

I've narrowed it down to the amp but wiring up my old pioneer which happily runs the splits and so fourth through the same wiring, though I've run a separate power from the distro and a separate earth. Just don't know what could be wrong? Time to give up on the amp perhaps?

Last time I turned to volume up to overcome a speaker cutting out I blew a $1000 set of front splits, so I would really, really advise against that.

As for why its doing it - this is only a theory, the more you turn the volume up the more power is pushed through - a weak/loose connection at some point finally makes a proper connection and you have clear sound.

Are you sure its the amp?

Swap with the pioneer and see how you go - if that solves the problem, its the amp. If not - its the sub.

Last time I turned to volume up to overcome a speaker cutting out I blew a $1000 set of front splits, so I would really, really advise against that.

As for why its doing it - this is only a theory, the more you turn the volume up the more power is pushed through - a weak/loose connection at some point finally makes a proper connection and you have clear sound.

Are you sure its the amp?

Swap with the pioneer and see how you go - if that solves the problem, its the amp. If not - its the sub.
Yeah well I'm not making a habit of it, just something I noticed when I turned the volume up thinking it was a quiet track or something playing.

The power is solid as a rock, TUFFTR and MicJaiy have seen that (MicJaiy helped wire it up) and its solid as. The earth is solid, I just did it then and theres no reason for it not to work, its exactly the same as how it was when I first installed the amp over a month ago and it never had an issue then no matter how hard or soft it played. The Pioneer is running perfectly, its in the car now and everything plays fine so I know its the amp, just don't know what exactly on it.

How do the ANL Fuses work? It crossed my mind that the fuse may be the issue, but traditionally if a fuse (or earth) is playing up the amp cuts out when you turn it up, not get better. I'm highly confused. Maybe I should be booking it in somewhere to get checked out.

Last time I turned to volume up to overcome a speaker cutting out I blew a $1000 set of front splits, so I would really, really advise against that.

As for why its doing it - this is only a theory, the more you turn the volume up the more power is pushed through - a weak/loose connection at some point finally makes a proper connection and you have clear sound.

Are you sure its the amp?

Swap with the pioneer and see how you go - if that solves the problem, its the amp. If not - its the sub.
I checked his connections at the amp on Thursday night. All connections into the amp are solid as a rock. Either way, ALL sound to speakers and subs are being affected..
The earth was terrible so Rhys fixed that which was the only issue I COULD find.
and yeah Rhys It aint the fuse. You've proved that theory by plugging the pioneer in and it working fine.

ANL fuses work like any other fuse, its just a metal link.

I'de say in that case, the rear channels on the amp are fried. Could be something relatively simple to fix, could be the RCA inputs.

To repair it, yes, take it to an amp specialist - if you were in Sydney I could recommend one place.....being in mexico cant help you much more :)

TUFF - wait, you just said that all speakers are affected? Im certain Lugo only mentioned the sub?

Im going to go with my first guess, leaking capacitors on the PCB - im quite possibly wrong - but hey, I'll put down a milky bar on it :)

Paul is correct, its all the channels, not just the rear. The problem last time was the rear because it was a faulty wire to the sub, this time every output is affected.

You didn't plug the power cable into the Earth on the amp and vice versa did you?

Time to take it to the hospital. :D

lol

Yeah I think I might. Fingers crossed its not too expensive.