I installed an amp in September 80wrms x 2 for running my polk comps; worked well, had good punch and crisp highs.

Today I noticed the output seemed really weak. It still put out sound, but not too much more than regular HU power - so I guess I'm only getting around 30-40wrms. I played with the crossovers, bass boost and gain on the amp, nothing worked. Turning up the gain just caused it to distort sooner.

What could cause this? I was wondering if maybe my ground went bad with the cold weather we've been having. Could a bad ground / power input cause this? Could just cold weather cause something like this in the amp?

Thanks

 

A bad ground can definatly cause current limiting and premature clipping...

Perhaps your battery is not doing so well in the cold weather and is causing strain on your electrical... ? (seems like a long shot)

Also consider that you may have got used to the volume, and now it dosent seem as loud as it did a few monthes ago... (this wouldnt surprise me in the least.. Im sure everyone on this board has experienced this effect)

Edit: get out your DMM and check voltage at the amp power terminals, and amp output voltage under load...

[ January 21, 2005, 01:45 PM: Message edited by: Haunz ]

 

I think the output transistors are going bad.
Better fix them b4 it takes out your PS
and other circuts in your output section.

HOw distorted is it? Listenable? really really weak?

 

Well, I tried it again that night and it was fine.
I jiggled all of the power cables while it was running and it still performed great [img]graemlins/dunno.gif[/img]

As for me getting used to the volume; no. My rear-fill (factory speakers running off the HU) were putting out more bass than my comps. That's not right.

Last night however, when everything was working again the front stage was loud enough that I couldn't hear the rear fill (the way I originally set up the system). When I experienced the problem, the rear-fill definitely had more bass out-put.

As for the output transistors going bad. Could that manifest itself in an intermittent problem like this? Or once they go bad they don't recover?

My thoughts are on the electrical system. I had some problems starting the car earlier in the day.

 

i can't see it being your outputs they usally work or they don't
could be cold sloder joints or something
have you switched your rca,s at the amp to eliminate them or the deck?

 

any moisture issues?

 

I`ve had bad ps mosfets that caused this problem.

If its not doing it all the time.. I would say they are fine then.

Try removing items from the system till you find out what is causing the problem.

 

Thanks, I'll wait and see if it happens again. If it happens again I'll be sure to have my DMM ready and a spare set of RCAs

John Vroom, very possible.
A week and a half ago we had a major thaw, then a snap freeze. The moisture in the air froze up my locks (and a lot of other peoples locks).

My thought is cold and moisture might be doing stuff to my connections.

Seahag: I'm glad you don't think its the MOSFETs. You scared me with that suggestion. (I've had amps do that to me in the past) I bought the amp brand new. While it is still under warranty, I really don't want to uninstall it and deal with all that crap.

 

agreed