Is it possible to shield fillament heaters?

[leadfootdriver]

I modded this amp by raising the heaters off the PCB. It did wonders, but the only thing I notice is that the amp will hum if I get near it with the guitar.

Could I wrap the heaters with tin foil with any result?

[Enzo]

That isn't what you are hearing. Your guitar pickups are getting the magnetic field of the power transformer.

[leadfootdriver]

Well that's that then. Thanks.

[masco]

You could shield the inside of the case. Or at least the part that's between the guitar pickups and amp chassis.

[Jazz P Bass]

Basically, what you are calling for is a Faraday Cage.

It would end up the size of a kitchen table.

[eschertron]

You could shield the inside of the case. Or at least the part that's between the guitar pickups and amp chassis.

Come to think of it, I've noticed a bunch of new amp heads with the cabinet entirely of metal. Lighter, easier to mass-produce, and possibly draining off some flux lines

[Enzo]

ALso easier and cheaper to stamp out in mass production than wood.

[mhuss]

There's two kinds of interference at play here, electrical HF stuff (noise and RF) and magnetic (hum). Normal chassis, foil and silver paint block the former, but not the latter. The only thing that attenuates magnetic interference is distance :-) or specialized metal called mu-metal that is formulated to conduct magnetic fields really well. This is the heavy metal used to shield better input transformers in studio equipment.

[leadfootdriver]

That amp must have been so noisy that when I fixed the heater noise, it revealed the magnetic effect.

[Enzo]

You can probably do that to most amps. Walk up to them when they are running and see if your guitar picks up the field.


My shop guitar picks up a 5150 from 3-4 feet away.

[Chuck H]

I've noticed a bunch of new amp heads with the cabinet entirely of metal.

Like cheapo lunch pails with tube amps inside

[soundmasterg]

Like cheapo lunch pails with tube amps inside

If someone got smart they would start selling advertising on their amps like those lunchboxes so you'd have Star Wars amps, and Fred Flintstone amps.....ok, maybe not so smart.

Greg

[Chuck H]

I actually don't think that's a bad idea. Maybe not a BIG seller, but I'll bet there's a demographic that is just nerdy enough to go for it. I remember when I was in second grade I had a Steve Austin lunch pail. No, not stone cold Steve Austin. The Six Million Dollar Man! Characters Embossed in the metal adding a realistic 3D graphic relief! All I can say is, if I still had that lunch pail I'd be very tempted to put an amp in it