US Acoustics amp overheating

leolufse · 09-27-2004, 02:52 PM

I installed a US Acoustics 2150 in a friends C5 this weekend. I have it bridged to a dual 2 ohm DA 10" wired for a 4 ohm impedance. It is running hotter than I expected and will go into thermal protection. It is mounted in a coupe on the rear wall.

Which of these choices would be a better fix:

1. Run the amp in 2 channel mode, one channel per voice coil on the sub. The advantage is the amp should run cooler in stereo mode, but the disadvantage is that the sub will only get a total of 300 watts instead of 450. Also, could this damage the sub?

2. Keep the amp bridged and wired up like it is, and add a 3/4" spacer to allow air around the back side of the amp. This is more difficult than it seems because there is limited space between the amp, sub, and hatch.

3. Add a fan.

TIA.

knewblewkorvette · 09-27-2004, 07:03 PM

I had the same amp and did the same thing you did, bridge both channels into a 4 ohm load. The amp did not like this set-up at all and after a few times of overheating the amp gave up the ghost and filled my truck with smoke

I had my doubts about the amp since a true amp (like my PPI) with 150 watts per channel should double into a 2 ohm load and quadruple the power going 4 ohn mono. The amp went 225 and 450 when (like my PPI) should have been 300 and 600.
I never had any problems with the amp for years and years til I wired it up in mono.
My advice, do the 150 watts into each voice coil. Make sure the input is mono and not stereo though, dual voice coils do NOT like a left and right input being different which can happen when you feed in a stereo bass input.
Good luck

PS One hard used US Acoustics amp for sale. Will sell for a penny and shipping costs

leolufse · 09-27-2004, 08:28 PM

Quote:

Originally Posted by knewblewkorvette

I had the same amp and did the same thing you did, bridge both channels into a 4 ohm load. The amp did not like this set-up at all and after a few times of overheating the amp gave up the ghost and filled my truck with smoke

I had my doubts about the amp since a true amp (like my PPI) with 150 watts per channel should double into a 2 ohm load and quadruple the power going 4 ohn mono. The amp went 225 and 450 when (like my PPI) should have been 300 and 600.
I never had any problems with the amp for years and years til I wired it up in mono.
My advice, do the 150 watts into each voice coil. Make sure the input is mono and not stereo though, dual voice coils do NOT like a left and right input being different which can happen when you feed in a stereo bass input.
Good luck

PS One hard used US Acoustics amp for sale. Will sell for a penny and shipping costs

Thanks for the advice. Damn US acoustics...

Grzldvt · 10-06-2004, 01:49 AM

Just to confirm, I had a 4165 bridged and it overheated. I tried the fan bit and it helped delay the thermal shutdown. As long as I had cool air running toward it, read that as a fan, AND an open window, or running the A/C so it pushed cool air back there it seemed to run hot, but not enough to shutdown until after 3- 3 1/2 hours.
Off to E-bay it went.... Seems the US Acoustics, don't like being bridged.