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Ground Loop?

I seem to have a ground issue with my phono preamp a Parasound JC3 Jr that just started about 3 months ago. I've tried very thing. A different Preamp (Moon 350p) replaced an Emotiva XMC-1 Different TT but still has the issue whether it's connected or not. I have 2 dedicated 20 Amp lines direct to fuse box and plugged them directly into the sockets bypassing my conditioner Audiance V8. It's a tapping sound with static but when I touch the loading pot in back it stops chattering but has a low-level hum. I have even sent it directly to Parasound and no issues were found. Going nuts!

128x128oldrocker52
invalid
1,080 posts
 

@erik_squires 

your luxman is up to NEC standards I assure you, it is internally grounded. You don't have to have an equipment ground to be NEC approved.

erik_squires
15,729 posts
 

@invalid AFAIK, the equipment ground is not an NEC thing but a UL thing.

AFAIK, you do not have to ground a metal chassis IF the power supply is double shielded from the chassis. The Luxman is not double shielded.

What does internally grounded even mean?

invalid
1,080 posts
 

@erik_squires the luxman amps i have seen pictures of all have the the class2 insignia.

erik_squires
15,729 posts
 

@invalid I'm not an expert in all things that need to be tested and approved, but based on my amateur reading of the requirement for a class 2 insignia, the device needs to be double insulated, and, again, from my eyeballs, it's no better insulated than any other power amplifier.

Please see the middle picture where I show the bare fuse holders, with the AC cables to the right of them.  That is what you would see immediately upon removing the bottom panel.

To my poor unqualified eyes that is not a class 2 cabinet.  Maybe some one else can help me understand how it is.

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