In Reply to: Hum from sub posted by docw on May 19, 2017 at 14:16:44:
Your amp module cools down and the hum goes away.
From what I'm reading even in the standby position it starts to hum after a while.
It's an overheating problem. Either a cap or a resistor is heating up and starting to screwing up the voltage to ground or to the FETs.
First thing you can try. Take the module out and if it's encased take the case off. Let it run (don't worry about the sound for now) until you usually hear the hum. If no hum it's the units cooling fins not keeping up with the heat the FETs generate.
Open it up take the amp module out and visually inspect it. Look for toasty resistors, hot spots, capacitors that "don't look right",etc...
You most likely will not see much. If not then get yourself a can of circuit freezing spray, let the hum start, spray each component and listen for the hum to fade away. THAT'S your failing part.
In my case it was the entire unit that was over heating. I had to mount the amp outside the cabinet and WELL vented. Try that first!
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Topic - Hum from sub - docw 14:16:44 05/19/17 (4)Follow Ups
- RE: Hum from sub - airtime 07:34:23 05/20/17 (0)