how connect shielded wire to pots?

[fogwolf]

3 questions:

1) When connecting a shielded wire to a pot not already directly connected to ground, where do you connect the shield - to the sleeve of the output jack?
2) What pot lug do you connect the shielded wire to? Is it always the same lug? If so I'm going to guess the wiper lug? If not, what's the rule for determining which lug to shield?
3) When shielding the inputs and outputs, the shields from those wires both go to the output jack sleeve, right? And the lug I'd want to connect to the shielded wire to for both these jacks would be the tip, right?

For example, I'm about to build the Tonepad FSH-1 (http://tonepad.com/getFile.asp?id=96) and I've read that I'll want to shield all the pots, especially the one for resonance control, but that one, for instance, doesn't already have a grounded lug.

Thanks!

[MikeH]

Use the center of the shielded wire just like any other wire.  Since the shield part only needs to be grounded at one end, you could connect it down at the pcb, or you could solder it to the back of the pot, like they do in guitars.

[fogwolf]

Thanks for the reply. I do understand which part of the wire is which, I just wasn't sure where to connect the *shielded* part to make sure it's grounded. So if I understand what you're saying, if I decided to connect the shield at the pot end, then instead of running a ground wire from the shield to the sleeve of the output jack (or by connecting it to a grounded lug of another pot, e.g. the ground of a volume control pot) I could simply solder the shield/ground somewhere on the back round part of the pot?

Use the center of the shielded wire just like any other wire.  Since the shield part only needs to be grounded at one end, you could connect it down at the pcb, or you could solder it to the back of the pot, like they do in guitars.

[fogwolf]

 Oops, meant to edit not reply to my own response.

[fogwolf]

Anyone?

[petemoore]

  Shield should be grounded at one end only.
  How that ground is made...discuss...
  If the ground is made the shield is a grounded shield [ie will shield].
  Soldering it to the back of the pot:
  If you have a big enough iron and get down to the pots metal, and can get the solder to stick, and don't melt the insulation of the shielded wire while doing so, it'll be connected to the back of the pot.
  It's been so long since I've tested for ground on a potback...I can't recall if the threads are connected to it.
  And because making the connection to the potback is 'tricky' and I don't like to trust mechanical ground connections, for me the shield ground would be made elsewhere...say a potlug or jacklug that has a hardwired ground connection.

[fogwolf]

Thanks!!

  Shield should be grounded at one end only.
  How that ground is made...discuss...
  If the ground is made the shield is a grounded shield [ie will shield].
  Soldering it to the back of the pot:
  If you have a big enough iron and get down to the pots metal, and can get the solder to stick, and don't melt the insulation of the shielded wire while doing so, it'll be connected to the back of the pot.
  It's been so long since I've tested for ground on a potback...I can't recall if the threads are connected to it.
  And because making the connection to the potback is 'tricky' and I don't like to trust mechanical ground connections, for me the shield ground would be made elsewhere...say a potlug or jacklug that has a hardwired ground connection.

[fogwolf]

Also, are there any rules regarding which lug of the pot to connect with the non-shield (conductor) part of the shielded wire? Does it not matter, just any lug? All the lugs? I'm assuming if it's a board running from the board to the pot that's not a ground wire it should be shielded (in the case of the FSH-1 where I've seen it recommended to shield all pots)?

  Shield should be grounded at one end only.
  How that ground is made...discuss...
  If the ground is made the shield is a grounded shield [ie will shield].
  Soldering it to the back of the pot:
  If you have a big enough iron and get down to the pots metal, and can get the solder to stick, and don't melt the insulation of the shielded wire while doing so, it'll be connected to the back of the pot.
  It's been so long since I've tested for ground on a potback...I can't recall if the threads are connected to it.
  And because making the connection to the potback is 'tricky' and I don't like to trust mechanical ground connections, for me the shield ground would be made elsewhere...say a potlug or jacklug that has a hardwired ground connection.

[petemoore]

  Shielding is overkill, except where you need it.
  You tend to need it when high gain is involved.
  Input wire is generally a good point for 'injected unwanteds' to get noticed, gain often goes up from there, so anything that does get in the SP stands a better chance of being boosted enough to be noticed.
  All that talk...and more I'm sure...
  That said, short wires where it matters, made by thoughtful layout is best except where shielding is better...the subject is much too general to be much more specific than that without being more specific.
  What circuit ? What layout ?...etc.

[petemoore]

Also, are there any rules regarding which lug of the pot to connect with the non-shield (conductor) part of the shielded wire? Does it not matter, just any lug? All the lugs?
  Hopefully a schematic assigns the potlug wirings.
  See GEO, 'the secret life of pots'.

[fogwolf]

Sure, but I more meant which of those wires need to be shielded. The more I think about it though it seems any wire from the board to the pot (other than those directly connected to ground) needs to be shielded to shield those signals traveling between them (please correct me if I'm wrong).

Thanks again.

Also, are there any rules regarding which lug of the pot to connect with the non-shield (conductor) part of the shielded wire? Does it not matter, just any lug? All the lugs?
  Hopefully a schematic assigns the potlug wirings.
  See GEO, 'the secret life of pots'.