I just finished my UcD400 amp today. Everything was fine for 15 minutes then one of the channel stop . Rails are OK at +-52 volts. Supply is Hypex HG. Any ideas?
Thanks a lot.....I'm desperate.
Thanks a lot.....I'm desperate.
Turn it off and unplug it for 10 minutes or so.... and then try it again. You may have triggered the short circuit protection.
Kevin Haskins said:
I was casually listening to music when it stop. I checked voltage and everything seems fine. Unpluged for 15 minutes and still nothing.
is the blue light on? is there running any current, I mean 6 or 54ma in 1 rail? if its 6 you're osc. is not running. Had the same a while back.
If that can help, I replaced the output filter cap with metallized polypropylene .68uF 250V MKP 416-420 on both module.
classd4sure said:
Done. What really bugs me is that the amp was working fine for 15 minutes before quiting. Volume was moderate.
At moderate levels pumping is highest,
Either 25 or 75% amplitude it pumps the most. According to Roger that can affect your pre amp, I guess a simple test would be swap channels and see what happens.
Either 25 or 75% amplitude it pumps the most. According to Roger that can affect your pre amp, I guess a simple test would be swap channels and see what happens.
classd4sure said:
output impedance is really high on the defective unit (megaohms). The other one measures around 10kohms.
It's probably disabled then. If you seperate the enable wires for both modules and just test the defective one (I'm thinking you're running both off one remote LED ??) you may see it blink as I think the protection they use cycles every 1 or 30 seconds.. no idea, can't remember how long.
You're measuring from the rails to the speaker output right so if the outputs were blown you'd see mostly the DC resistance of the filter coil and hear a 60hz hum.
If you're reading Mega ohms you're looking at a mosfet that's being held off. Maybe you could try it with a different pre amp or swap modules channels (try the bad one on the good channel dont' try the good one on the bad channel) maybe you can rule something out that way.
You're measuring from the rails to the speaker output right so if the outputs were blown you'd see mostly the DC resistance of the filter coil and hear a 60hz hum.
If you're reading Mega ohms you're looking at a mosfet that's being held off. Maybe you could try it with a different pre amp or swap modules channels (try the bad one on the good channel dont' try the good one on the bad channel) maybe you can rule something out that way.
classd4sure said:
I swapped the modules on the monoblocks. The problem follows the defective module. No hum, no DC at the speaker output. No blinking on the LED.
Hope this help. I REALLY appreciate your assistance....really,
I think I found something. Speaker ground is the the same as chassis grounded on the defective unit.
......but that was caused by an XLR to RCA adaptor in the input. When I remove the adaptor, speaker ground is isolated from chassis ground.
......but that was caused by an XLR to RCA adaptor in the input. When I remove the adaptor, speaker ground is isolated from chassis ground.
tomahack said:
Speaker ground is also the module's chassis ground there's two connections for it but they're at the same potential.
You didn't float the module off ground or anything did you?
It looks a little high to my unexperienced eyes. I read a few mV in mine. I hope you do your tests with a cheap pair of speakers. Do you have music now?
Be careful with your PS caps while swapping. They may be charged 😱
Avoid further damage to yourself or your module. Wait for the cavalry 🙂
Normally speaker ground must be "floating".
Sorry not to be of any help. I am sending you good vibrations, though 🙂
Good luck.
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