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In the Forum: Analog Playback
In the Thread: The last phonocorrector: “End of Life" Phonostage
Post Subject: Grounding arrangementPosted by N-set on: 11/21/2011
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The grounding I have employed is a mixture of a "local star" and GND plane (I've obviously copied it from the Cat).
I did pay a lot of attention not to have loops. Here is my grounding scheme. I wonder if there are any obvious errors?
There is a switch breaking lifting the GND plane from the chassis. If I lift it I get a horrible pickup, I think magnetic
100Hz from the PS (the hum disappears instantly when switching all off).
The connection between the signal and the PS box is via a shield (braid) on the umbilical.
Then at PS, the chassis is connected to the GND
pin of the IEC power inlet (for the time of experimentation I connect to the power ground).
Actually, connecting the scope across 470k output resistors (at the RCA's) the pick up with the phono switched off
is of the same amplitude as the ham with the phono switched on (but for eample the pick up on the 2M grid is negligable).
Cheers,
N-set
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