[sdiy] RE: DX7 grounding?

[Dan Gendreau]

> Interesting... is the chassis connected to audio ground too?
>
> Most synths sold here in Germany come with two-prong mains plugs, and
> so did the DX7. The DX7II however had a mains plug with protective
> earth, but this was not connected to audio ground (AFAIR). If
> protective earth is connected to audio ground and you have more than
> one device wired this way then it's ground loop time.
>
> Ingo

AFAIK, It does not appear to be connected to audio ground.

In the schematic, the chasis was originally just connected to some sort of odd
capacitor isolated center tap of 2 small transformers before driving the main
power transformer. The earth ground is now tied to the chasis as well. The
Analog and digital grounds are generated after the main power transformer in the
rest of the PSU.

No problems so far using outlets on different circuits in my studio. If I do run
into a ground loop at a gig I have an IEC cord with the earth pin removed for
such an occasion.

-Dan G.