NGD - GK MB200 - hum/buzz with a MIM Fender

[Killed_by_Death]

Bingo - Found 2 conductor shielded 22 awg wire at Home Depot.
They sell it by the foot too.

 

[B-string]

That should work. Attach the black and shield at the jack as ground, use only the black as ground at the pots.

 

[Killed_by_Death]

Here's a shot of the pots & wires as they are now.

 

[Killed_by_Death]

That should work. Attach the black and shield at the jack as ground, use only the black as ground at the pots.

I found out today that the coating on the inside of the cavity isn't conductive. They have a screw with a ground wire going into the body, but I don't really see the point of that w/o conductive coating.
It will be at least another week before I can get that shielded wire, so I'm going to try bypassing all the pots & stuff with a couple of alligator clips & wire in the meantime, just to see if the problem is in any of the solder joints of the pots.

 

[B-string]

If you at least twist the wires going to the output jack you should get some reduction, no loose loops, but not not overly tight.

 

[Killed_by_Death]

I twisted the pair leading to the output jack as much as I could & it reduced the buzz significantly.

 

[B-string]

Install the shielded cable for the jack later when you can and things should be much better. I don't understand why this isn't done at manufacture, but as I said before it is the source of problems.

 

[Killed_by_Death]

Thank you dude!

I went through a lot of possible scenarios. A lot of people said it needed shielding in the cavity. That's why I bypassed the pots & stuff, thinking the problem was in one of those solder joints.

The local luthier told me no amount of shielding would help with a Mexican, because they're overwound so much that they are sensitive to Radio Frequencies.
I know for a fact it's from EMI/RF, because if I hold my mouth just right, i.e. turn to just the right angle, it's gone. That would mean I'm parallel to the waves at that point, instead of perpendicular, where it's worst.

I actually think a little more winding/twisting on those wires might just do the trick. I will compare it to my Mexican Stratocaster & if it's at or below the noise level, I'll leave it be.

So glad someone suggested twisting those wires, LOL!

Live and learn!

 

[B-string]

LOL. Yes, twisting is a standard practice in lower gain situations for noise control. In high gain (like between the amp's tone stack input and the instrument pickups) shielding is the ticket. If anyone stops and gives it a close look, good quality pickups use shield wire. Why would you not continue to use shielded if it was important enough for the pickups to have it. Even instrument cords are shielded wire.

 

[Killed_by_Death]

Why would you not continue to use shielded if it was important enough for the pickups to have it.

Cost. A huge part of manufacturing outside the USA is to pay less wages, but unfortunately they go ahead & cut corners on materials as well.

Yes, twisting is a standard practice in lower gain situations for noise control. In high gain (like between the amp's tone stack input and the instrument pickups) shielding is the ticket.

I actually know the benefits of twisted pair, but didn't think it would make a difference in such a short run.
Sometimes I forget to fall back on my knowledge of electricity & electronics when dealing with guitars. It's all very basic electricity theory, but man that stuff can do some crazy stuff sometimes.

I still refute that Orange Drop caps are better than others, if you overlook their tolerances are better than standard capacitors.

 

[Killed_by_Death]

Problem persisted this morning, so I connected the bass to the amp using my A/B switch with ground lift & an isolation transformer.

The isolation transformer did the trick, so the EMI can be removed. I will try installing the shielded wire next week & if that doesn't work I will get a choke for the instrument cable or even a tiny one to put between the tone pot & the output jack.

 

[Killed_by_Death]

I finally decided it was the amp, & got an Ampeg PF350.

Argh, Ampeg is the SAME!
Now I have to decide which to keep. The Ampeg has more features, but the GK is tiny & has FOUR tone controls.
I think the GK would be better for playing guitar also.

I just got the shielded wire in today, so I will try that tomorrow.