1482 Hum

[Platefire]

When I turn my guitar volume down I get a hum but when I turn my guitar volume wide open it goes away. Other than that the amp works fine.I'm thinking this is grounding problem or 60 cycle hum problem, right?

Another clue, at low volume on the amp, the hum goes away but the louder you turn the amp up, the louder
the hum

[scstill]

Not specifically from a 1482, but I also get guitar hum, its frustrating, and so many variables...
I know its guitar connection because when unplugged the amps are generally quiet.

I'm often in a small room close to amp, When I move away from amp hum gets less

Also I get a lot of body grounding hum, its impractical, but when I connect the bridge to my body the hum goes away

Hum is often less when I set the guitar down.

Single coils hum but humbuckers or reverse wound not so much.

Also noticed that amp and guitar tone controls affect the hum.

Looking forward to any other wisdom that comes from the forum....

[tubeswell]

I'm thinking this is grounding problem or 60 cycle hum problem, right?

Yes. I’d say so.

[Platefire]

I just don't remember having that problem about 20 years ago when I rebuilt it. It was quiet as I recall. I'm going to try it in some different outlets and see what that does. Of course in 20 years something may have moved or went bad. I did try a new tube in V1, but the same thing.
As you see I'm trying to avoid going inside due to having Afib and I have the worlds worst record of getting bit by DCV. So I been avoiding the inter workings of my amps lately

[Platefire]

I cancel this post. I took the 1482 into the kitchen and fired it up. Perfectly quiet and that was with a guitar with P-90's.So I'm happy, a little embarrassed but glad my old amp is working like it should. Trying it in another outlet should of been the first thing i did

scstil---did you install the modern fender style switch jacks for your inputs? I believe that one of the big improvements that can be done. Those original input jacks were grounded by the mechanical connection of jack to chassis(as shown in pix) which after 50 years gets corroded and loose

[scstill]

yes I always use shunt style input jacks on the amp input (new builds and restos)
As I mentioned, the amps are generally quiet when the guitar is not plugged in.

The point I was making is that guitars act as a noise pickup.
I have also copper wrapped the cavities of most of my guitars. Doesn't do a lot IMO.
The biggest improvement is when I ground my body to the guitar.
Maybe I should just play metal then it would be a desirable effect :-)

Another big noise impact is the LED ceiling lights. Have tried adding a cable magnets to LED line no avail.
When I play in the dark it is more quiet.  :-)

Have also tried AC line filters but doesn't seem to help much
Thinking guitar is like RF Noise antenna
Wonder if adding a cap across the amp input would help for some noise filtering...

[Platefire]

I wish I could help you but don't know what to say. Looks like you covered all the bases. My other 1482 is completely stock all the way down to the two conductor power cord and last time I fired it up was quiet. There is got to be something you missed.

I was going to tear mine down and fire it up with the circuit exposed and chop stick it and check it from head to toe but----thank God it was the outlet and not the amp. If you want to go to a little extra work, maybe you could post some gut shots and let us look and come up with some things to try?

[Willabe]

The biggest improvement is when I ground my body to the guitar.

What do you mean by this, it's not clear at all.

[Willabe]

I have also copper wrapped the cavities of most of my guitars. Doesn't do a lot IMO.

With what kind of PUP's?

And did you connect the copper tape to the guitars ground?

Should be a very large difference doing this with single coil PUP's. Humbuckers don't need it most times.

I used shielding paint on my Strat, made a huge difference, knocked the hum way down.

[scstill]

Experiment Connecting guitar to players body by clipping wire to the bridge and touching the other end to players skin. Seems to be same when hands are on strings. Likely grounds body to guitar.

Copper clad is connected to guitar ground. It likely helps but there is often still noise.

Most noise on hot SC less on HB.

The Amps are pretty quiet without guitar. Noise goes up with guitar. Maybe just the way it is 

[Platefire]

I've only had one guitar that gave me bad hum issues, a Telecaster. I installed all new electronics/wiring/neck pickup plus installed one Stu Mac shielding kit, followed their instructions and that fixed it!