Localized cages as RF suppressors.

[Reeltarded]

I noticed some 1/2" braid a couple weeks ago while surfing for ancient knobs, got me ta thinkin'..

Instead of wrapping coils around inputs, and Hi-Z anything -because I don't like what shielded wire do's to's signals (mostly)- anyone ever seen big braids to tunnel signal wires around the chassis? I am thinking it's like a wormhole that I can use to have the signal magically (and scientifically!) pop up where it goes from where it came.

The idea is to take 1/2" or larger braid, pinch it in a mold, and weld it in with a torch.

Do I think my amps need it? Nah, I was just thinking (that it would be crazy)... like I have the time..

[Cantplay]

How about shielding the high voltage AC instead? Isn't that the source of the noise?

John

[briane]

I would expect a lot of HF rolloff (lot being subjective'

Interesting experience last night - guy had a speaker cab not working too well - I started wiggleing the cabs wire to the speaker - cuts in and out - lets shotgun it.

New wire and the cab sounded about 100 times better - it was high quality wire I replaced with 'rat shack' wire - just goes to show maybe the color of the wire does matter - a whole lot (well not color - but manufacturer)...

[Colossal]

Briane,

What wire did you use if you don't mind my asking.

Thanks,
Dave

[Reeltarded]

I use lamp cord in speaker cabs, and sometimes for connects. I have a pile of dual 14/2 and then I have twistlocks with 10/3. heh

[DonMoose]

I would expect a lot of HF rolloff (lot being subjective'

A wire run down the center of a 1/2" diameter shield would have about the same capacitance as a wire of the same length run down the center of the cavity in a steel chassis.

http://faculty.wwu.edu/vawter/PhysicsNe ... llCap.html

C = e0*(A/d) where:

e0 = 8.854x10-12 C 2/N.m2 -> permittivity of free space ~= permittivity of air, thickness of non-air dielectric << remaining free interplate distance

A = area of the two plates -> surface area of the wire (in m^2)

d = distance between plates -> 1/4" minus diameter of wire (in m)

You're going from hundreds of femtofarads per foot to tens of picofarads.
You'd need to be one of those guys who can hear the difference it makes to have a wooden volume knob vs. metal or plastic.

[Reeltarded]

Why all the numbers?

When you guys talk in maths.. it makes me remember my drinking days, favorably.

[Cantplay]

Just looked up the mini coax I use, its 16.7 pf/foot.

How many dB rolloff would that be at say 4-5KHz?

I know I can hear a little rolloff when I hook 2 18ft guitar cords together, but thats 36ft.

John

[DonMoose]

Why all the numbers?

When you guys talk in maths.. it makes me remember my drinking days, favorably.

On the off chance someone feels a need for an actual number in place of my usual handwaving, I try to provide a 'why' for my opinions.

[Structo]

Hehehehehe