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Universal Power Supply PCB

6L6

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Joined 2010
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Is it PSU hum or a ground loop?

Basically everyting shouldattached to the same ground bus on the PCB, and the two PCB side’s ground need to be tied together at a place of your choosing. CL60 attaches there as well, to chassis.
 
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Got it. Originally I had tied the two boards together at the front of the PSU and the back of the PSU with bridges and the hum was louder.

Removing the ground bridge at the front lowered the hum significantly.

In the picture below I circled where there are 2 ground pads per board in the middle (in red). I used this spot for the amp board grounds but the CL-60 and speaker grounds are at the back on the ground buss connecting the two boards together (in green).

I believe it’s a ground loop. The amp barely gums with the inputs shorted.
 

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Yes. It does have a very low hum with inputs shorted so I think it needs rewire and the V+,V-,and grounds twisted tighter. It’s 14 gauge wire and it’s a bit tough to work with and doesn’t fit the pads very well.

I’m considering replacing it with 16 or 18.

I’ll try the star with the rcas connected there as well. I’m currently using a twisted pair.
 
I’m working on re-wiring the amp tomorrow but wanted to ask.. the AC wires are VERY close to my ground bridge and currently the speaker out ground wires are on my rear ground buss along with the CL-60.

Should I instead move my star ground buss to the middle of the PSU board (circled in red) to get these wires away from AC wires?
 

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Ok I see that the PCB is still available.

I want to get this configuration using a spare audiosector psu board:

xxx.png


Am I correct that I can join PG+ and PG- to create COM as in the schematic above?

I think I got the naming scheme on the audiosector boards, but I missed what "PG" stands for!?!?