Real McTube preamp stompbox - can anyone identify this schematic symbol?

[Johnny85]

Hey there

I hope someone can help me, this is my first post here but I've been using info from the site for a while, have just done a Geofex-faithful Fuzz Face with Fuller Mods and a very special Stratocaster with inbuilt NPN germanium Fuzz Face under the scratchplate (photos soon in a different post).

Anyway, I'm thinking of having a go at building Fred Nachbaur's "Real McTube Mk 2" (see http://www.dogstar.dantimax.dk/tubestuf/mctube.htm#index1).  I was looking at the schematic and I just cannot understand the way the input and output jacks are wired.  I mean I've never seen the symbols before, it looks a bit like antenna loops.  If they were connected at the "loops", then everything would be grounded which seems quite pointless, and if they weren't connected then where's the point in drawing them in?  I just don't get it.  There's also one of those little weird loops "connecting" (?) the wiper of RV2 to ground.  Sadly Fred has passed on so I cannot ask him.  His site is really interesting, I would recommend checking it out.

Here's a link to the schematic: http://www.dogstar.dantimax.dk/tubestuf/graphics/mctube2m.gif

So can any of you experienced and wise builders help me out?

Thanks

Johnny

[maarten]

Hello Johnny,
it simply means these connections are made by using shielded cables: the outside of the cable is connected to ground to prevent the inside of the cable of working like an antenna (picking up all kinds of undesirable signals). So you were right: it has to do with ground, but no, the signal itself is not connected to ground - the "loop'' is drawn there to show you that this connection should be shielded from interference.

Maarten

[Johnny85]

Thanks Maarten!

Now that you have said it, I can see that it makes perfect sense, as those connections are all the signal paths.

Thanks again.