I needed a volume control to hold me over until i can get my Passive Line stage built. Digging around my junk piles i found a P&G pot that
I slapped into a project box with a Cheapo RCA Cable cut in half for In/Out. this works, but there is a bit of minor background hum.
I never even thought about the ground loop that would be created by tying the In L-R and the out L-R grounds together. but sure enough HUM.
Ok, so now, to avoid that in the construction of the Passive Line stage. How should i ground the I/O?? I will be using isolated panel jacks. I would imagine i need to somehow break the loop on the output side of the attenuator? I thought i read someplace that a small value resistor to ground would be enough to break the ground loop, yet still provide enough of a return path. But will this then add to the loss through the box??
So if we have the Input of the box going to pins 1 & 3 of the pot, and the output from the Wiper and then what should we do with the output ground? 100 ohm resistor to Pin 3 of the pot and the output jack ground???
Please Advise
I slapped into a project box with a Cheapo RCA Cable cut in half for In/Out. this works, but there is a bit of minor background hum.
I never even thought about the ground loop that would be created by tying the In L-R and the out L-R grounds together. but sure enough HUM.
Ok, so now, to avoid that in the construction of the Passive Line stage. How should i ground the I/O?? I will be using isolated panel jacks. I would imagine i need to somehow break the loop on the output side of the attenuator? I thought i read someplace that a small value resistor to ground would be enough to break the ground loop, yet still provide enough of a return path. But will this then add to the loss through the box??
So if we have the Input of the box going to pins 1 & 3 of the pot, and the output from the Wiper and then what should we do with the output ground? 100 ohm resistor to Pin 3 of the pot and the output jack ground???
Please Advise
At the moment i dont even have jacks, i just have a cable running in and out of the box. and the hum is still there if i run just one channel.
When i got my C-J amp, it had a ground lift adapter on the power cord. The ground loop seems to be cause by the grounds of the audio gear and the audio cables. lifting the ground of the amp makes it go away.
When i got my C-J amp, it had a ground lift adapter on the power cord. The ground loop seems to be cause by the grounds of the audio gear and the audio cables. lifting the ground of the amp makes it go away.
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