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Grounding questions

I’ve had an issue with a slight hum through my system for a long time. System consists of Jolida Fusion Preamp and JD1000P amplifier. Both plugged into Futman Elite 15 power conditioner. It’s not dependent on any sources. Hum is there when amp is on. 
 

I have a dedicated line for the outlet to the Furman. Hum does not increase with higher volume. 
 

Maybe it’s an issue with the power amp but it could be an issue with the house wiring. The house is 62 years old and the fuse box is original and not grounded. Before I pay $800 to have it grounded, what do you think is causing the hum? It’s not cable related as I’ve swapped interconnects. The pre and amp are connected by a balanced cord. 

128x128mschott
fuzztone's avatar
fuzztone
5,625 posts
 

Answer your own question with an $8 receptacle tester. Then make sure that the green wire is attached on both ends.

mschott's avatar
mschott OP
133 posts
 

FYI the hum existed before the electrician installed the dedicated line. Im

not home to look at the receptical at this time. 

gs5556
1,235 posts
 

First things first: Power on the amplifier without the preamp. If the hum goes away then connect the preamp. If still no hum connect the source components one at a time to the preamp until there's humming. Then we can narrow it down.

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mschott's avatar
mschott OP
133 posts
 

Thank you. I don’t remember if I used a cheater prior to the dedicated outlets which by the way are not GFCI. I isolated the power amp and there is hum from both speakers. When I plug it directly into the wall, there is hum from both speakers but the frequency seems a little different. 

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