I had a MTX 6304 amp installed this weekend. I have the first two channels running a pair of Focal seperates up front and I bridged the rear two to drive a Focal 10 inch sub. Because I have the sedan with Premium they could not mount the amp to the rear seat. I had them mount the amp to the back of the sub box. If I run the system for 45 min. or more the amp will overheat. I have run less powerful amps this same way with no issues in previous cars. Is it running this hot cause its a hight watteage than amps I have used in the past? Please help.

"Dont start none, Wont be none"

 

It depends on the specific amp and if it's getting enough airflow. It could easily happen if the amp is sandwiched between the trunk and the box. You might want to put a fan in or find some way to circulate the air. I've tested to see if mine will overheat (PPI DCX) and they did once after two hours, while driving in 100 degree weather with the windows down, at the loudest volume that I listen at.

 

Could this be an issue of bridging two channels of a four channel amp? I always known that bridging a two channel amp is OK, but I've never heard about bridging just two channels of a 4 channel amp. Looking through the owner's manual of the MTX amp, is this a recommended usage?

04 G35s 6MT BS Aero Kit/Nav/Prem
Warning: Objects in Mirror Are Losing!

 

yeah.. ive done the same thing with less powerfull MTX amps. They are 2,3,or 4 channel capable. None have overheated. And yes, air flow is a problem as it is between the seat-back and box. Although its never been an issue in the past. Im thinking of adding a second amp and un-bridging the 4 ch to see if that helps any.

"Dont start none, Wont be none"

 

That may help, just make sure the amps aren't too close to each other or the problem may be worse.

 

Make sure the impendence of the woofer is not lower that the manufacture's recommendation when bridging the rear two channels.

A dedicated sub amp would be better. An efficient D-class mono amp would be best.

I had a stereo amp that I bridged to drive my sub. It would often overheat and shut down. I replaced it with a D-Class amp which resolved my problems.

Good luck!


BLKSNAKE - '04 G35 Coupe
Check out my hidden sub! [img]/w3timages/icons/laugh.gif[/img]

 

The sub amp is in the mail... its an MTX Thunder 302. I hope this solves the problem. thanks for the replies everyone.

"Dont start none, Wont be none"

 

An impedance check is definitely the first thing. But a small fan can really work wonders with overheating amps if the normal convection isn't cutting it. I had to use a relay to turn the fan power on when the remote wire was turned on. But after adding a fan, my amp went from getting hot to the touch to being comfortably warm even after a long drive.

 

Ill have to do that. I think I have a dual vioce coil sub. Although Im not sure if both coils are hooked up. if they are... then thats an issue.

"Dont start none, Wont be none"

 

Well, maybe. DVC subs come in different flavors. If you have a two-2 ohm DVC you can wire them in series to get 4 ohms. If you have two 4 ohm DVCs you'd have to connect only one of the two coils up to keep the amp happy but limit the sub's power handling. Or you could wire them in series to 8 ohms which would keep the sub happy but waste half of the amp's power. If your amp is getting hot it's most likely not the latter, as the amp would probably run pretty cool if fed an 8 ohm load.

If it's the 2-2 ohm variety and you only hooked up one of the coils then that's definitely a problem. The amp would be getting overworked and sub would only be using half it's coils!

-- Rob

 

The sub I have is 2x 4 ohm coils. Ill have to take it out of the box an see what they did with them. So your saying that 1 coil should be hooked up in order to make my amp happy. The whole 8 ohm series way. Hmmmm.... what would you rather have for SQ.?

"Dont start none, Wont be none"

 

Running off one coil isn't a really good idea ... you're likely to blow the sub as it will only handle half its rated power. I'd be more comfortable giving the amp 8 ohms. But you're going to get a lot less output, especially if it's at 2 ohms now.

Can you cancel/return that Thunder 302 amp? You're going to have the same problem with it. Because you can only produce a 2 or 8 ohm load, you really should buy a monoblock amp that produces optimal power at 2 ohms. The Thunder 302 wants to see 4 ohms to produce 425 watts.

*edit*

Doing some more research, it seems there's some debate about using a single coil.

http://www.adireaudio.com/Files/Tech...oilDrivers.pdf

Seems you can "short" the other coil (connect + to -) and have it work okay, although still with less power handling.

-- Rob



<P ID="edit"><FONT class="small"><EM>Edited by djrobx on 06/03/04 03:34 PM.</EM></FONT></P>

 

Thanks for that link. Pretty interesting stuff discussed. I got the 302 in the mail from ebay. So its not going anywhere. Ill mess aournd with it and see what happends. thanks again.

"Dont start none, Wont be none"