OTL Asylum

MA-1 Silver Edition missing "ground"

79.13.234.196

Today I decided to explore the origin of a faint "crackling" noise I was hearing in one of my MA-1 monoblocks, a noise that disappeared when I pushed a 6AS7G tube a bit more into its socket. I opened the chassis and found the culprits: two missing solder joints in the tube socket lugs. Quite disappointing in such a beautifully crafted piece of gear.

After soldering the joints I discovered that the central "ground" (third wire) connection in the IEC mains socket is unused; so the monoblock is not "grounded" at all? And why is that? I believed that proper grounding was mandatory for electric devices. I have a 230V version, maybe it's different for the native 110V versions?

Cheers.

N.

Follow Ups:

RE: MA-1 Silver Edition missing "ground" - Frank 21:24:27 02/17/08 (2)
Which series MA-1? I've got very early versions and mine are the same way WRT the lifted ground on the AC in. IIRC the manual states the preamp is to supply the ground thru it's connection with the amp in order to avoid ground loops.
- RE: MA-1 Silver Edition missing "ground" - Ralph 12:45:22 02/18/08 (1)
  If the ground of the IEC connection is plugged into the wall you will have a ground loop and the system can develop a rather prodigious buzz.
  - RE: MA-1 Silver Edition missing "ground" - Nuvistor 15:12:07 02/19/08 (0)
    Thanks for the explanation Ralph.
    
    I guess the pre- and power amplifier grounds are connected via the XLR cable, right?
    
    Anyway, the MA-1's sound just GREAT.

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