Power supply is in its own enclosure, with a 7-wire umbilicus.
That ground buss wire is probably making a loop, should go.
I hadn't thought of SMD grid stoppers, very clever.
The chassis is made of aluminum, that back plate where the jacks are mounted, so if I want to connect a 0.1uF ceramic disk between signal ground and that plate I'll have to get crafty. Solder might not go to the aluminum.
E the lug for the TT ground wire is directly grounded to the back plate, and then has a wire in the umbilicus back to the PSU where it grounds that chassis, too. So the signal grounds are grounded thru that copper buss bar, but also thru the red wires to the PCB and back to the ground lug via the blue and yellow wire. What a mess.
First step would appear to be to remove the wire between the GND lug and the RCA jacks, it appears that there are potentially several ground loops, next I would would remove the bus between the RCA jacks. I would next add the 0.1uF caps directly from the RCA GND to chassis. Ferrite beads would seem advisable, and maybe on both leads.
All is not lost. 😀 Looks very tidy overall.
All is not lost. 😀 Looks very tidy overall.