2A3 finally finished

好手工！

Your question is not very specific. Using relay for what ? Are  you referring  to muting on output signal or relay for switching input signal?

[quote:d3e777f143="WINDWSS"]dear acc photo,

i had make a pasive volume control, what is your advice on connecting the ground cable.

temporary i connect the all the ground wire to 1 point of the casing, is it correct? (the casing only have 1 volume pot and RCA)[/quote]

For passive volume, I do not think it is really that matter. Have you got a chance to connect to a pre-amp or poweramp. If there is no hum, it will be fine.

You got what you pay for.......永遠是好料才有機會好聲......

Long signal wires may result in signal losses and impedance mismatch , just aware that not all pre-amp and power-amp work with passive volume....

2A3 must go for RCA Flat Black plate....!