Owner has 5 of these and 3 have gone into protect mode, all the same symptoms. All look the same but not sequential serial numbers. He's getting someone technical to look at the speakers and leads and as they are used from a diesel generator maybe a problem there. All failed in use , not abuse, not failing at switch on , and no earlier odd noises before failing. Anyway these 3 amps show clip LED on both ch, and then drop into protect. I've the schematics for them but before going down false paths ,anyone been here before. ? I've looked inside one and all healthy appearance. SMPS fires up enough to deliver about +/- 100V rails, both ch, for half a second , fans ok and relays click over but then drops into protect. No excessive mains current draw at any time. This one and the others , both channel o/p measure about 13 to 15K to ground and not tied to + or - rails so will assume PAs are ok at this stage and maybe falsely going into protect.
Crest Audio Pulse 2 1100 power amps, 1999
Jul 09, 2010
4 Replies
I'm wondering if it could be related to prolonged brownout if used with generator set all the time. Anyone know the definition of brownout? mains 5 percent down? 10,20% ? Google thinks I'm trying to get Gordon Brown out
I'd consider a brownout here in the US of A to be in the range of 75 to
90 volts out of 120. Certainly noticeable by amplifier and other electronics performance by any competent music tech or even a musician.
These people think they are Douglas Adams' Disaster Area with 10KW of power , now having to make do with 4KW, perhaps less loading on the generator will keep the remaining 2 alive for longer , if a brownout issue.
It's as easy as a voltmeter plugged into the amplifier mains and occasionally monitored.
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