Amp Cuts Out From Heat

[sorted vti]

hey.

i had an alpine v12 t757 amp running a very large output sub (ground zero)

its worked fine up till a week or so ago. but then it suddenly just cut out. to feel the amp it was extremely hot but the speaker amp was very cool to touch. after further inspection the sub was also knackered aswell.

i guess it was the sub that killed it because the sub was still playing minutes before it cut out but really really badly.

suspect its the coil that is gone because its now really hard to push the cone in and out!! lots of dragging noises.

so after that i put another v12 in and a kenwood sub (lower powered sub and lower powered amp) but now it has started to cut out after a while. just wondering why things have started to overheat. ive had this v12 in the car before and it was fine. didnt cut out at all. just cant understand why its doing it now.

ive bought another t757 v12 to replace the old one but dont want to put this in as i dont want to ruin that aswell.

also dont know why the speaker amp is cool but the sub amp gets way too hot!

i have the sub amp mounted flat on top of the sub box and the speaker amp is mounted at a 45 on the side of the box.

cheers guys

[DJ Wozza]

I don't know what power cables you are running but check them for correct grade

for the currant they are expeccted to run, plus the earth is a very sound connection

to a suitable ground point.

I would think the Amp has either been sending a clipped signal (which you might not be able to hear)

and that has overheated the speaker coil...result kaboom.

The other possibility is overheating caused by poor ventilation, which doesnt sound

sound to be likely considering the placement of the amp. I run, and have run Alpine amps

pretty hard before and have never had one pop.

I would check the gains are set correctly, as per the instructions with the amp or the Alpine

website. No disrespect intended at all mate, but it is very easy to overdrive an amp so it

starts putting out a slightly clipped waveform, which leads to overheating of the Amp, and

coil meltdown for the Subwoofer.

This is in no way meant to be a definitive help guide mate, just what I have learned being passed on.

I hope this helps and you get it sorted for the Grasshopper Meet.

Best regards

Woz

[sorted vti]

cheers. i must admit i do have it up loud all the time. just thats how ive always had it and i just wonder why things are starting to overheat now.

going to install everything a bit neater so going to get some fans in there. maybe that might help.

[worldentropy]

cheers. i must admit i do have it up loud all the time. just thats how ive always had it and i just wonder why things are starting to overheat now.

going to install everything a bit neater so going to get some fans in there. maybe that might help.

Hiya Sorted ..

General tips: make sure that your gain is set correctly (per one of the earlier replies). This is the number one killer of amps. Also make sure that there is good impedance matching all round, i.e. make sure that the output from your driver amp (one preceding the sub-amp) is impedance-matched to the output of your sub-amp. This is either a standard 600/120 Ohm drive or, on rare occasions, a standard 4 or 8 Ohm. That is imperative.

With standard equipment, impedance matching should not be an issue. Just make sure that you use the right outputs into the right inputs. Also ensure that you cable neatly, correctly and using good quality speaker cable where necessary. Remember to ensure that all your speakers are installed with correct polarity, i.e. all your +ve terminals from speakers are feeding into +ve outputs from our amps, all way round.

Finally, ensure that your overall impedance of all connected speaker networks (e.g. if you are running a cross-over arrangement, with say a tweeter, a driver and a (sub)-woofer arrangement) is not below the minimum stated for your amp (usually 8-Ohm, 4-Ohm (common) or 2-Ohm (rare)).

Another point to check is, offcourse, earthing, like DJ mentioned. To give you an idea of how important this is, very good earthing is a start. Excellent earthing is how things should be. Use good quality earth braids, to solid, chassis earthing points. That said, I don't quite agree that either a clipped signal or earthing is an issue for overheating. Clipping occurs when amp inputs are being over-driven, and in that case, clipper and Zobel networks kick into action to protect your speakers rather than the amp.

Some of the above will cause your amp to overheat, most importantly of all impedance matching on amp in/out and to your speakers and speaker networks if applicable.

One more thing .. I'm quite surprised that an Alpine amp would overheat due to impedance mismatch or indeed any of the issues above; I'd have thought that for the premium one pays for those toys that Alpine would have had the decency to implement simple clipping/matching/overload protection.

Hope this helps. Happy listening !!

Cheers,

Ahmed.