Hi,
After almost 3 years from my last repair; see
https://www.eevblog.com/forum/repair/help-fixing-and-understanding-a-simple-rc-circuit-from-dayton-audio-sa1000/ one of my SA1000 has developed a noticeable hum in the connected subwoofer speaker. Since I have two of these amplifiers, if I replace the amplifier for the subwoofer, I get a noticeable improvement (much reduced hum sound) in the sound output of this AC hum.
Can anyone over here give me some pointers to help troubleshoot and repair this issue?My Right subwoofer has a hum and my left subwoofer is quiet like it should be.
My room has single electrical circuit with multiple electrical outlets in the room. The electrical circuit goes from Left to Right side of the room.
At the start of the circuit is where I have my Left subwoofer connected which is quiet with no issue. This electrical circuit then goes to the front of my room where I have Panamax M5400-PM power management and line conditioner unit installed. All my home theater electronic devices are connected via this Panamax conditioner. I have an electrical wire going from the HIGH CURRENT (Bank 5) to the right side of my room as a dedicated direct wire to my right subwoofer. This right subwoofer has developed a noticeable hum.
The sound level of the hum does change on its own when other devices in my home are turned on or off or randomly as well. Sometimes this hum is loud while at other times it is not that loud but still noticeable. I originally thought that I have developed some kind of group loop issue or DC offset issue. I tried adding
Emotive CMX2+ and this has not made any difference. Next I moved the subwoofer electrical wire from High Current Bank 5 to Voltage Regulated + EMI/RF Noise Filtered Bank 4 on my Panamax M5400-PM and that did not make any difference as well. I was thinking maybe my Panamax bank has gone bad or the whole Panamax unit has gone bad. Finally, I changed my Right amp with the Left amp and the hum is immediately reduced (not fully gone but low enough that I can live with).
This makes be believe that some component inside Dayton Audio SA1000 of my right amp that was doing some type of line conditioning has gone bad in its power supply. This is now causing my subwoofer to have this AC Hum. Here's the sound I am hearing
50 or 60Hz Group Loop Noise (time marked) as a reference (this is not my video, equipment or room).
I can share any pictures as needed. Can someone guide me in fixing this hum as well?
Thanks for your help in advance.