Effective electromagnetic shielding?

[JamieMcC]

I found out something unexpected today, I was looking to purchase a pair of RCA Splitters and looking on their shop page these RCA end terminals caught my eye.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi.ebayimg.com%2Ft%2F4Pcs-Pure-Copper-Gold-Plated-Hi-End-Carbon-Fiber-RCA-HI-END-AC-Audio-%2F00%2Fs%2FMTIwMFgxNjAw%2Fz%2FScwAAOxy6-tSAJEW%2F%24T2eC16J%2C%21%290E9s37F%2CGdBS%21JEVz%21Cw%7E%7E60_57.JPG&hash=fcd567cab7ed5bfc194e5718613b4cb74d30e1e5)

I thought hey they would match with the carbon top plate on the Crack I have just completed and started me thinking about making a couple of sleeves to put over my own terminals.

But what caught my eye and jogged my memory was this little sentence in the sales pitch.

 "Carbon Fiber housing offer effective electromagnetic shielding"

 As a newbie I don't know how and what situations this would apply with audio equipment and I solely added the carbon plate to my Crack for cosmetic reasons.

But I can offer a couple of know instances where carbon fibre is deliberately not used in manufacturing composite components due to its ability to block radio signals these are well know examples with carbon thickness of less than 1mm.

Carbon fibre mobile phone cases can block the phones signals to the point the phone becomes useless as a phone and manufacturers often use a dyed glass fibre substitute to get the same carbon look for the case but without the associated interference issues (its also about a tenth of the price of carbon).

Carbon is often used in the manufacture of radio control airplanes and gliders for its strength and light weight however the nose sections where the radio receivers are located Kevlar or e glass is substituted because again the carbon blocks the radio signals to the receivers which causes loss of control during flight.

Is there any consensus of opinion regarding the benefits of such shielding methods and how it might be applied to tube amplifiers or if is it needed at all. If so what might respond well to trying such shielding on something like the Crack?
 

[mcandmar]

Interesting didnt know that. I knew it was non conductive and creates all kinds of complications when used for cars as the norm is to use the metal chassis as the ground plane. Similar to old Lotus Elans with fiberglass bodys where all the wiring had to doubled up for the - side causing all kinds of weird and wonderful glitches.  Think English wiring with dodgy grounds!

As for shielding the amp, i believe any EMI interference or the classic cell phone barp de barp noises are picked up from the valve itself not the amp circuitry, hence those metal shields you see fitted over them sometimes. Certainly it cant do any harm to shield it all, no different to housing it all inside a metal box.

[Grainger49]

   .  .  .   Think English wiring with dodgy grounds!   .  .  .   

I feel the "Warm Beer" quote coming on.

[mcandmar]

There is a cure for that..

[JamieMcC]

As for shielding the amp, i believe any EMI interference or the classic cell phone barp de barp noises are picked up from the valve itself not the amp circuitry, hence those metal shields you see fitted over them sometimes. Certainly it cant do any harm to shield it all, no different to housing it all inside a metal box.

Ok interesting thanks, I can only get the Crack to make those barp de barp noises with the mobile phone is right next to it.

Next time I do some carbon work I will knock up some carbon tube shields and see what happens.