Contour Enthusiasts Group Archives Forums Modifications Audio Is my amp busted or just not fully operational?

Well it finally happened. I tripped the thermal protection circuit switch again of my CC special profile Baja 75watts per channel amp playing some old 70's bass heavy funk music while it was 90 plus degrees with 70% humidity here in NYC but only this time the amp was damaged to the point where I had to replace the heavy load, two audiobahn amd6 midbass drivers rated at 3ohms wired in series used in freeair mode, with a lighter load, one tc sounds 6.5" driver mounted in a sealed box firing thru the rear deck hole because the amp made a rumbling sound a low and high volume when powering the heavier load. I thought that this rumbling sound was a blown driver but after removing the heavy load and testing it at home it was discovered that neither driver was damaged any further. So what kind of damage could my amp have gone thru where it makes a funny rumbling sound under a heavy load a sound that it does not make when under a light load.

One thing must be said though and that is I must decide quickly whether to purchase a single channel 1ohm stable amp from JBL (the Bp150.1 or Bp300.1) or go with a 1ohm stable two channel amp from Kicker, or MTX to be used in bridged mode. Within another post a discussion on what was better a 2 channel amp bridge or a one channel amp with equal power was made. Is it true that a 1 ohm stable two channel amp is not 1 ohm stable in bridged mode. If this conclusion is correct then I will go with the one channel amp. My only concern with the JBL amp is that the bass boost is only 6db and the max input voltage is 4v while the profile baja is 18db and the max input voltage 7volts (I think) The reason I must quickly decide is because I need more bass for if it is not thumping (figuratively what I feel thumping is I am not driving with a happy smile on my face down the road. For a freeair load in the trunk gives deeper lower bass than a small sealed box can and I like my bass sloppy and lose not tight unlike my preference in women which is the reverse.

Dont think you did any damage to the amp, if you had the 2 mid bass drivers in series, thats 6ohms, any amp could handle that in any temp. Now the noise you may hear may be from distortion due to lack of voltage to the amp while under a slightly lower load (now if you had 1.5 ohm that is another story)

Check your grounds make sure they are tight and check you battery connection as well. If you have a voltmeter check the voltage at the battery and then at the amp. If there is a 0.5v or greater difference you need to check your install.

actually KnuKonceptz they were wired in parallel
anyway the small box with a single 6.5 inch driver I am using back there now also makes a rumbling sound so it is indeed the amp that has been damaged

I found the JBL BP300.1 Single Channel Amp for $199.99 at cartoys.com and so will order it from them probably mostly because it is a 1ohm stable amp offering 150 watts into 4ohms which was what I was getting from my Profile Baja (blue CC special) 200 when it was bridged and used in mono mode.

The JBL BP300.1 is NOT 1ohm stable. It is stable down to 2ohms.

BTW, here it is for $135 if you still want it. JBL BP300.1

Neither was the Profile amp, I guess this would explain what caused his original problem.

Well the jbl manual says differently, SVT Colin
and KnuKonceptz anyway I found the profile 600msx on sale for 99 and might purchase that amp instead though my only issue here is that it is big 16 inch long.

look here to see jbl specs

http://www.jbl.com/car/product.asp?cat=AMP&ser=POS&prod=BP300.1
http://manuals.harman.com/JBL/CAR/Owner%27s%20Manual/bp_om.pdf

search for the word "stable"

I stand corrected. The entire BP series of JBL amps is 1ohm stable.

However, there's no power increase in going from 2ohms to 1ohm.

BTW, I'd take the JBL even though it's an extra $35 over the Profile. I've owned a couple of Profile amps, and they've been mediocre performers. I haven't owned any of the JBL mono sub amps, but I've heard nothing but very positive reviews. I'm pondering picking up a BP 1200.1 to power a couple of 10s I've got.