Grounding of Shielded Wire

[MacL]

Hi All,
I am from the tube guitar world now dabbling with HIFI. I have a successful Budgie SE under belt but I have a couple question as I choose my next project and review the builds of others.
1) Grounding of shielded wire- I getting conflicting information on this- the guitar gurus are telling me to always ground one end of a shield wire (inputs for example) and I am looking at photos of some of the builds of HIFI here and not seeing this done. I have personally built both ways and I not sure If I can tell/hear a difference...
2) I had great success adding a 3.5 mm input for a smartphone on my Budgie SE with the 12ax7 preamp- will a 6SL7 (as in the Clementine) also work well with the input from a smartphone like a Droid or Iphone?
Thanks

[Geek]

Hi,

Still ground one end.

Lots of HiFi builders use both ends for lack of experience in insanely high-gain amps and a small ground loop may not show on an 85dB efficient speaker.

Cheers!

[coolhandjjl]

That's why newer RCA connectors have a plastic bushing around them, to make sure they stay isolated on one end.

[soundbrigade]

My collegues, specialized in EMC at SAAB ment that an shield that was left ungrounded at one end was a perfect antenna for picking up noise from the outside world. But as some has pointed ot, ground the shield at both ends create ground loops som y EMC-friends suggested a small cap of some pF or nF to "ground" he ungrounded end.

[Geek]

Then they're doing it wrong.... Ground the shield at one end, but have a drain wire from your connector

[Blair]

That, or the way I do it if I need the shield to be grounded at both ends (assuming good quality wire), is to cut my buss ground and use the shield as the buss. I rarely have to do it that way, but it works.