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Phono stage hum

Dipping my toe into Tubes for first time.

Have been using simaudio moon lp5.3 phone stage.

today trying Manley Chinook tube stage.

getting what sounds like ground loop hum with the chinook and my thorens 160 super... tried with a different turntable (cheap teac) and no hum....

any ideas? 
otherones
rotaryphone
159 posts
 
Do you place two TT on the same spot?

I would move the phono amp away from the other equipment as far as you can and see what happens. 
otherones OP
12 posts
 
Both TT tested in same spot and I have also tried moving the phono stage as far away as I could... same result 
noromance's avatar
noromance
1,780 posts
 
Try using a cheater plug on the amp. This removes the ground connection and therefore the loop. 
rotaryphone
159 posts
 
My next guess is TT itself is not grounded properly within TT chassis. I would check RCA solder joint and make sure it checks out.
otherones OP
12 posts
 
My amp (parasound a21) has a ground lift option and the hum is still there when enabled.  Would testing a cheater plug do anything different?

I will confirm the TT rca solder joint to make sure it is ok - but if there was an issue wouldn’t it be present on the other phono stage (sim audio lp5.3)?
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