Unknown switch on 20/20

[Soloist]

I've noticed that my recently bought 20/20 has a switch on the back, mounted besides the V1 tube. I couldn't find it in the online manual.
What is that? Is it a ground lift or what?
Any help appreciated.

 

[phaboo]

DON'T TOUCH IT!

That's the self-destruct switch!

 

[Soloist]

DON'T TOUCH IT!
That's the self-destruct switch!

Oh my God! :shock:

 

[Gusfmm]

Ground lift. There should be a tiny sticker affixed by the switch.

Unless you have specific ground loop issues (an annoying 60Hz noise in your audio signal), you should leave it in the ground position, not lifted.

 

[Soloist]

Ground lift.

As I supposed. Thanks.

There should be a tiny sticker affixed by the switch.

No sticker (anymore).

Unless you have specific ground loop issues (an annoying 60Hz noise in your audio signal),

50Hz here in Europe.

you should leave it in the ground position, not lifted.

Yes, I know. Thanks for the advice and the clarification.
Now it's just a matter of finding out which is the "not lifted" position.

 

[V!N]

Now it's just a matter of finding out which is the "not lifted" position.

The one with the 50 Hz hummmmm. 8)