shielding an input jack

[dude]

I installed a metal Switch Craft jack in a Blues Junior, the cream board III, revised edition with the 1 meg to ground before the 10 ohm grid resistor. I isolated the jack from the chassis. If I hang the jack the hum is much better but in place in the the chassis right above the traces, I suspect a shielding issue. I've read these metal jacks need to be shielded, how would that be done..?  Or any info appreciated. 

[sluckey]

I've never found it necessary to shield the input jack in a low gain guitar amp. Your granny's snuff tin would be an easy solution.   

[dude]

Not Granny's but my old weed tin snuff. 
 I guess I could bend up a tin box to enclose the jack. But hanging outside the chassis with shielded wire from jack to board, hum is much better, maybe the grounded cover might help, never added it. But I too never had an issue before replacing plastic jacks with Switch craft ones...?

[dude]

It also is important you wire the jack correctly  , l didn’t used the wrong ground on the old plastic jack to bd.
Guess, l’m starting to make old age mistakes l never made before, gett’n old is a bite in the butt.

[PRR]

> I suspect a shielding issue.

"Suspect"?? Or is it sounding crapped-up? If you actually said what the problem is, I skipped reding at that point.

"Usually" the area below the jack IS the stage the jack feeds. Those resistors and pins should not be radiating crap? Even so, the problem is that stage, not the jack?

[dude]

I wired the ground to the jack tip, wasn’t thinking that the bd was flipped. I’m surprised it even played with the hum, reversed the ground and tip points and bingo, hum gone. I don’t like PCB boards, those small trace pads lift so easily. The Blues Junior’s PCB board is junk, you pull the tubes ten times and that’s about it, the solder point pins lift.

[bmccowan]

I don’t like PCB boards, those small trace pads lift so easily.

Yup - Heck, we are still repairing and modding amps built in the 30s, 40s, 50s, 60s just replacing a few caps and resistors. New PCB amps are designed for the landfill along with your laptop computer, and cell phone. How's that for a grumpy old man comment.