PA amp problems....

[bryan_kilco]

Hey guys, not really sure if this is the correct place to ask this type of question...sorry if it's not.

Anyway, we have a basically brand new (about a month) Behringer Europower PA amp to power some big speakers. Everything worked fine until yesterday, suddenly the sound would totally cut out....seemed like it only happened when the singer got loud. We normally have the 25dB pad set so we can crank it a bit more without clipping. I turned that off, and noticed that as soon as the clip light comes on is when the sound cuts out. I did some research online and cant seem to find any similar issues. Maybe someone here can help?

 

[if6was9]

Sounds like you're pushing it too hard and the protection circuitry is kicking in, shutting it off.
If this is happening at really low level then it could be due to overheating- check to see if the fan is working properly on it. If the fans not going it can't cool down and will clip alot earlier. Usually when a fan goes its just a broken solder joint somewhere and a easy enough fix

 

[ahjteam]

yeah, you also should leave atleast half rackunit ventilating space for the amplifiers, like this:

http://www.thomann.de/fi/thon_1he_rackblende_luefter.htm

 

[bryan_kilco]

Sounds like you're pushing it too hard and the protection circuitry is kicking in, shutting it off.
If this is happening at really low level then it could be due to overheating- check to see if the fan is working properly on it. If the fans not going it can't cool down and will clip alot earlier. Usually when a fan goes its just a broken solder joint somewhere and a easy enough fix

Well, the thing is.....we have pushed it way harder before and it was fine. Last night it was BAM - as soon as he did a decently loud yell or scream it would cut in and out . Thought it was overheating, but ....I dont know. The unit didnt feel warm at all, and the problem happens right as soon as you turn it on. It doesnt seem to happen at low volumes. Its definitely not the mic or cable. It's still under warranty so we are ok there, just kinda bummer that its already giving us shit when its barely 2 months old. Thank you guys for your input.

One other thing I considered was the extension cord. We have a 50 footer basically going from the outlet, across the room, to a surge protector. I think next practice we may try to move the pa head over to the outlet and see if that changes anything. It just never did this before and we havent changed the way we use it.

 

[bryan_kilco]

well, we had practice last night and this weird problem came back after a little while. Definitely seems like it happens when the thing gets warmer.

We are running 2 big speakers - two 15" subs and horns and 3 tweeters in each cab, and I never heard the brand of them. Only thing it says at ALL on the speaker cabs is "PA SOUND", and yesterday we removed one of the speakers to see if there was a rating on the back of the speaker...nothing. Maybe we are running this all screwed up and the ohms are mismatched? It's getting returned and we'll try another, but I'm afraid if its the speaker/ohm issue, it will just keep coming back to haunt us.

 

[bryan_kilco]

problem solved (I hope)!

Took the head and one of the speakers to GC (where they orignially bought the head) and talked to some people. Apparently we were OVERpowering the speakers. So now we gotta drop about $800 on some new speakers.

I noticed another thread about PA amp problems and it reminded me of this thread, figured I'd give it a bump for anyone who may care.

 

[arv_foh]

problem solved (I hope)!

Took the head and one of the speakers to GC (where they orignially bought the head) and talked to some people. Apparently we were OVERpowering the speakers. So now we gotta drop about $800 on some new speakers.

I noticed another thread about PA amp problems and it reminded me of this thread, figured I'd give it a bump for anyone who may care.

I really don't think that is your problem and GC just duped you into buying $800 of new shit. If you are overpowering the cabinets, you just turn the amp down. It won't overheat and clip out, unless you are running an ohm load that is too low for the amp (ex. the amp is only stable down to 4 ohms and you are feeding it a 2 ohm load), then you can run in to problems.

 

[TheWinterSnow]

you said it yourself, the red Clipping LED is lighting up, which means you have exceeded the line level voltage going into the amp. Most Solid State poweramps, have a massive limiter on the inputs to prevent the input voltage to the amp itself from clipping, which is dropping your volume. Rule of thumb for power amps, turn their volume all the way up and use the master volume one your mixer as a volume adjustment, if your master fader is at unity and still not loud enough, well if you have a large power amp, you might want to turn the fuck down because thats a little overboard.

 

[NocturnalTendencies]

Chiming in late having discovered this thread via a Google search as to why my Behringer Europower EP2500 PA was cutting out tonight... the fan was locked up solid from dust (embarrassing to admit, flog me). Cleaning out all the dust with compressed air did the trick as the fan regained function and the amp stopped cutting out as a result.

Lesson learned.

Cheers