Amp running hot...??

Emerica2843 · 01-28-2006, 06:31 PM

ok heres my setup:
Two 12" Sony Explod 1200W XS-L121PS subwoofers
2-Channel Kenwood 800W KAC-7201 Amplifier

I just had this installed at circuit city the other day. After they installed them and I left circuit city, about 10 minutes later I had some rock music on, not even at a high volume and the song didnt have a lot of bass in it, and then the subs and amp went dead. I popped the trunk and saw that the blue light on the amp was turned off. I immediately drove back to circuit city and they spent about 10 minutes looking it over and found that both of the 25A fuses on the amp were blown, so they replaced them with 25A fuses. Then one of the technicians said "if I were you i would start looking for a new amp soon, thats something internal thats wrong with the amp and its not a good sign." Whether that is true or not i dont know. Anyways, everything was fine for the rest of the night, until last night when i had the subs on and the fuses blew again. I took both of the blown fuses out of the amp and noticed a sticker by the fuse slots that says "30A x 2". I then went to walmart and bought a pack of 30A fuses and installed them and the amp worked after that. Is it possible that the amp was blowing fuses because they were 25A instead of 30A? Also, i started checking the temp of the amp after 15-20 minutes of listening to moderately loud music nonstop. The amp was hot enough to burn my hand if i touched it all the times i checked it. Is this normal with all amps or is my amp not powerful enough to power my subs? The amp has a cooling fan inside of it too. Any help/advice would be great. thanks

mushin · 01-28-2006, 06:59 PM

800W = 66A @ 12V, so it's not too surprising being fused at 50A would blow. Depending on the type, amps can be extremely inefficient, so they can get quite hot. Whether yours is abnormal is hard to say, but I'm hardly an expert. It sounds to me as though you were just using the wrong fuses and things should be ok now, but if you're concerned you might want to get it checked by a real expert (not a circuit city goon).

Emerica2843 · 01-28-2006, 07:22 PM

will the amp be damaged when it gets that hot to the touch?

mushin · 01-28-2006, 08:02 PM

I doubt it. And if it is getting hot enough to damage anything, it's probably because it's already malfunctioning.

Superduck · 01-28-2006, 09:08 PM

That amp is rated for 150w X 2 RMS, so for average usage, it's only pulling 25s total. You're not running below 4 ohms, are you? I'm assuming the installers didn't bridge to mono and run them in series or something.

It shouldn't be getting that hot under normal loads. At peak output, with the gains cranked, it will probably get pretty hot, but it should also have a thermal overload protection. Most amps have them.

Do you hear any distortion when you turn it up? Perhaps it's wired wrong. Your amp isn't capable of running at 2 ohms stereo. If it is, it'll overheat quickly.

If you play bass-heavy stuff at a high volume for any period of time, does the amp cut out or shut off? You're slightly under-powering the subs, so I wouldn't crank it up too loud. Otherwise, this setup shouldn't be too bad. Did you buy the amp new or used? Have you had it for a long time?

Cheers,

Kris

silveralt · 02-08-2006, 06:40 PM

Depending on how they hooked the speakers up. I did this with my amp, too. Having them hooked up in parallel will introduce a 2 ohm instead of 4. Make sure they're hooked up in stereo or you will just have this problem again. Not sure if I explained the ohms correctly. But make sure the speakers are hooked up in stereo and not mono.

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