[fetteler]

Having the arm tube connected to the chassis is fine and will not cause an earth loop unless something else is wrong like a problem with the insulation to the internal wiring of the arm allowing the screen to contact the arm tube.

Perhaps before going any further it would be a good idea to measure the resistance between the signal screen and the chassis to see if there is continuity? If there is then track down where it is occurring. Disconnecting the signal cables from the arm at the tag strip is where I would start...

Also, have you checked that there is no connection to the headshell at one of the cartridge pins? Many Shure cartridges ( for example) have a little removable tag between one of the pins and the cartridge body.


Steve.