I think you should tidy up the wiring, and avoid twisted groups that do belong together (it is not clear from the foto).
it looks messy but all the teisted pairs belong together.
not messed up groups which don‘t belong…
I had a humming issues with one of my amplifiers and it was caused by the power transformer from the preamplifier that I was using. Moving the preamplifier away from the amplifier got rid of the hum. I also had hum issues caused by bad input cables.
I don't find this in the BOM please what is the reference for 3R3 | 5 Watt's green resistors ?
They are mox, metal film or wirewound type ?
They are mox, metal film or wirewound type ?
it seems i found the problem.
i was using some outlet from another wall with my amp.
after i connected it to the same outlet where my preamp is connected the humm is gone.
seems i have a problem with my AC in my apartment.
i was using some outlet from another wall with my amp.
after i connected it to the same outlet where my preamp is connected the humm is gone.
seems i have a problem with my AC in my apartment.
Thanks
I have a very slight hum with my No. 176 amp.
Though - 100 dB/W speakers, hum only audible with ear within about a foot / 30 cm from speaker driver. I measured 300 - 400 uV AC at the outputs with the inputs shorted. Less than my M2 before I went to heroic shielding measures on that one.
I figure this is "to spec", and the slightly higher susceptibility to hum / less good PSRR had been the reason why Nelson implemented the more elaborate RC filtering on the filter board - as he stated in the manual 🙂.
Best regards,
Claas
Though - 100 dB/W speakers, hum only audible with ear within about a foot / 30 cm from speaker driver. I measured 300 - 400 uV AC at the outputs with the inputs shorted. Less than my M2 before I went to heroic shielding measures on that one.
I figure this is "to spec", and the slightly higher susceptibility to hum / less good PSRR had been the reason why Nelson implemented the more elaborate RC filtering on the filter board - as he stated in the manual 🙂.
Best regards,
Claas
The Meanwell supplies tie the secondary ground to AC line, so the potential
for ground loop is there. You can test for this by isolating the AC line ground.
for ground loop is there. You can test for this by isolating the AC line ground.
If possible, it's worth trying to reverse one or both plugs to minimize the AC line problem.
You can use a DVM to measure the residual AC voltage on the chassis. This is not uncommon.