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PA Help
Old 12th November 2009
  #1
Here for the gear
 

PA Help

Hi,

I have a Kustom KPM4080 PA that I have been having problems with. It's this one pictured below:

A friend lent it to me so I had something to use for practicing with the boys. However it recently stopped working right, and I'm not the in financial situation (see: college) to be throwing down the cash for a new one. I know it's not a high quality unit, but I'm hoping there's something I can do to fix it. It will power on, but no sound will come through any of the channels. If I unplug it and plug it back in, it will power on and work fine for a few minutes but will then suddenly go mute again. I took it apart and poked around to see if anything was loose or something and hit it with some compressed air, and when I put it back together it was doing fine for about 20 minutes...but then it went quiet again and I had to once again unplug it to get it to make a meager few minutes of sound. While it is "mute" it is emitting a kind of quiet humming from the speakers, but that is it. I am currently only running one microphone into this. Does anyone have any suggestions about what to do to remedy this problem?
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PA Help-41nxl-2bwi7sl._sl500_aa280_.jpg  
Old 12th November 2009
  #2
Lives for gear
 
David C.'s Avatar
 

You need to make friends with someone who is studying electronics. They could get some trouble shooting experience and chances are the actual part/s failing are not expensive. In repairs, you're paying for the tech's time for the most part.
Old 12th November 2009
  #3
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S.Filpansick's Avatar
 

Keep in mind that this is purely a guess, as you didn't give very much info, but I'd look at the type/number of speakers that you have plugged into it. If it's only designed to run at 8 ohms, and you're running it at 4, or even 2 ohms, you're going to overheat it.

Most "modern" amps have a thermal protection circuit that will shut the amp down if it overheats... once the temp is back within range, the amp comes back on. My band had this problem with a Mackie powered mixer...


Hope this helps!
Old 12th November 2009
  #4
Here for the gear
 

I feel like the overheating issue may be what's causing it. I am running it into two small Kustom speaker cabs (I think they may be KPC12Ms? I'm not too sure). Anyways I will look into this when I get home and let you know how it goes, thanks!
Old 14th November 2009
  #5
Here for the gear
 

I'm still having the same problem. Here's a little more info:

The powered mixer is rated at 4 ohms, 80 watts. There are two speaker output jacks in the back, and each one says 8 ohms on it. I have two small monitors I am trying to connect to this, each one of these has an input and output jack. The monitors are each rated at 8 ohms (one of them also has an attenuator and is switchable to 16 ohms). How should I be connecting all of these?
Old 14th November 2009
  #6
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S.Filpansick's Avatar
 

Quote:
Originally Posted by rags View Post
I'm still having the same problem. Here's a little more info:

The powered mixer is rated at 4 ohms, 80 watts. There are two speaker output jacks in the back, and each one says 8 ohms on it. I have two small monitors I am trying to connect to this, each one of these has an input and output jack. The monitors are each rated at 8 ohms (one of them also has an attenuator and is switchable to 16 ohms). How should I be connecting all of these?
Ok, well I'd guess that the speaker jacks are parallel, so plugging one 8 ohm speaker into each jack will result in a 4 ohm load. The same would be true of plugging speaker "A" into the amp, and plugging speaker "B" into the output of speaker "A".

80 watts at 4 ohms is not very much power... so you may need to crank it to get any usable volume, which could overheat it. How loud are you running it?

Try running it with only one speaker hooked up (8 ohm load) and see if the problem changes.

If that makes the problem go away, then I'd say it's still a heat issue.
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