Terrible hum when TV is on in room

[alexpigment]

Does anything else automatically turn on when you turn your TV on by chance? Soundbar, streaming device, etc? Also is it possible to turn off WiFi and Bluetooth on that TV? These shouldn’t cause a problem but it’s at least something to try that doesn’t involve buying a new TV.

[eyemack]

Good thought. My Sky mini-box and receiver (for sound) turn on, but if I just turn off TV and leave them on, there is no hum. Also, sadly, wi-fi and bluetooth are not enabled on the TV.

[GilmourD]

I'm almost wondering if the TV itself isn't grounded correctly and its emitting stuff that would normally be shunted to ground.

[alexpigment]

I'm almost wondering if the TV itself isn't grounded correctly and its emitting stuff that would normally be shunted to ground.

Most TVs these days don't have a grounded cable anyway; they're almost always 2-prong in the US at least. I would imagine they just cheaped out on the power supply components. I've never tried them, but Samsung does have a budget line ("Crystal UHD") to compete in price with TCL/Hisense/etc, so maybe there are some corners being cut. Or maybe this is just a weird anomaly that we'll never get to the bottom of

[eyemack]

What I do find strange though, is that if it’s the TV (or anything else come to that), why is it only affecting the JM and none of my other guitars?

[alexpigment]

What I do find strange though, is that if it’s the TV (or anything else come to that), why is it only affecting the JM and none of my other guitars?

If we ignore the pickups and just focus on the wiring, you can probably see that there is significantly more wire going back and forth inside a JM compared to a Strat or Tele. The wiring is what you're trying to shield from outside sources. If you simplify the circuit of a JM and just make it go pickups > switch > volume (and tone) > output jack, and you twist all the wires, you'll have a quieter guitar (again, ignoring the noise coming in from the pickups).

As for the TV causing the noise, it really doesn't make too much sense to me in general based on my own experience with TVs, so I'll allow the possibility that there's another factor involved.

[eyemack]

That’s true, the wiring is more complex. However, it is now fully shielded whereas the Strat and Tele are not. Also, the noise levels (as shown in a previous post) are pretty much the same for all 3, except for the one circumstance, i.e. hands near pickup when TV is on.
I would have thought that if it is the more complex wiring, then the residual noise would be louder too.
Who knows?

[alexpigment]

But it *was* louder before shielding, right? I think I might be missing the point you're making.

[eyemack]

Good point!

I guess we'll never truly get to the bottom of this one.

Thanks again.

[eyemack]

I've read that the paint used in the Am Pro II cavities is shielding paint. Can anyone confirm that?

[Larry Mal]

I've read that the paint used in the Am Pro II cavities is shielding paint. Can anyone confirm that?

Is it black/very dark grey in color and dull, no gloss? If so that's Fender's shielding paint. They usually do a pretty shit job with it, though, and I've never felt their shielding paint was good enough.

It's not a very good shield, but it can work, however to use it effectively you would want to build up a few coats, letting it dry a day in between. Fender is in no sense doing that.

Basically, if you buy a Fender or Gibson or any other brand name guitar, just assume there's little to no effective shielding in it whatsoever that you can't see and just plan on doing it.

[eyemack]

Thanks. I wasn't going to do it, happy with the copper process as above somewhere in this thread!
Does shielding paint have to be black? I'm sure I've read that it can be mixed with powder to make the body colour. No?

[timtam]

Thanks. I wasn't going to do it, happy with the copper process as above somewhere in this thread!
Does shielding paint have to be black? I'm sure I've read that it can be mixed with powder to make the body colour. No?

If you're seeing body colour in the cavities that's the finish coat. The black shielding paint is applied earlier and so is underneath.

[Larry Mal]

Thanks. I wasn't going to do it, happy with the copper process as above somewhere in this thread!
Does shielding paint have to be black? I'm sure I've read that it can be mixed with powder to make the body colour. No?

Well, I hate to disagree, but the times I've seen shielding paint on Fenders it has not been underneath the body, then again, maybe I wouldn't see it if it was.

I'm skeptical, though.

I have never heard of shielding being mixed with guitar finish paint. I think it would throw the color off. The cheap shielding paint is carbon mixed in with the "paint" part of it, the better kinds are nickel and silver mixed in.

Here's the silver.

But even if it is technically possible to mix the shielding substance in with the paint without totally distorting the finish, it wouldn't make any sense to do that since you'd either have to spray the whole guitar with shielding finish at added expense and no real benefit, or spray the bulk of the guitar with the non-shielded paint then switch to the shielded stuff for only the cavities, again, expense and time.

My experience with Fender is even when they bother to do any kind of shielding at all, it's just some crudely slapped on carbon paint that doesn't really do anything.

[eyemack]

Thanks again. I wasn’t speaking from a position of knowledge, just stuff I’d read.
So, as the texture of the paint in the cavities is so different to the main body, I guess it’s an iridescent lacquer that’s applied last that makes that difference? Mystic surf green on my JM looks very different in different lighting.