RR3 shielding/high pitch feedback question

[rc2904]

My RR3 gets the 'high gain squeal' at relatively low gain. I have narrowed it down to what I believe is a shielding issue. It is definately inside the guitar because nothing else makes that squeal while plugged into my amp.

Aside from the high pitched feedback, I get a metallic ping sound when i tap the body.
At first I thought microphonic pickups so I potted the detonators.
Then when it did not go away I replaced all of the wiring and electronics.
Then I played with different wiring diagrams and grounding methods.
Then I tried eliminating/simplifying the wiring by excluding combinations of switches pots, etc.
Threw in an old jackson j90 humbucker thats been sitting around for 20 years.
Tried different metal and plastic humbucker rings.
Swapped out known good humbuckers from another guitar.

The only things that have not been swapped out this whole time is the wood, bridge, and shielding.
It looks like raised lines where shielding tape is under the paint on the sides of the pup cavities and the paint looks different on the bottom where the ground screws to. Does this guitar have conductive paint as well as shielding tape?
Should I try running a new screw to a different spot in the pup cavity to get a better ground to the shield or should i sand the cavities out and start with fresh shielding?

If anyone has any ideas other than shielding I am open to suggestions.

[jdr94]

Post some pics of your control cavity. I bet its the same issue. Hot and ground leads are crossed.

[rc2904]

Right now the control cavity is pretty bare. I dont even have any pots/switch/etc wired up.
Duncan distortion with red and white soldered and taped. Green and bare are twisted together and connect to the floyd+shield grounds and runs to negative (sleeve) from the jack. Black is connected directly to the hot (tip) wire from the jack.
I also checked the wiring specs on the 3 other pickups ive tried in this body.

[jdr94]

Well that only leaves the pickup to be the problem. Bought it new?

[rc2904]

The duncan detonators came with the guitar and were potted to try to fix this, the jc90 i tried had been in a box for 20 years, the duncan distortion and bc rich pups came out of a warlock that does not have this issue. Every pickup i toss in here does the same exact thing.

[jdr94]

Hmmm im assuming you made sure that the ground is going to the sleeve and hot to tip? Other than that I have no idea whats wrong. The guy with the kelly had his black and bare twisted together which is what I think his issue was. Not sure about yours.

[rc2904]

Yeah. I had to pay extra attention to that because the detonators are made with green hot and black ground (bare off of the baseplate is twisted into the black wire). Then the bc rich was just bare (ground) and white (hot). Also the sound when you touch the bridge/strings on a reverse wiring is a lot lower pitch than what im getting.
So do you think bad shielding or ungrounded shielding can immitate a microphonic pickup? The similar symptoms im getting are the high pitched squeal and also when i tap the wood I hear a metallic ping with reverb (reverb is likely from tremolo springs).

[jdr94]

Are you sure? I thought duncans were bare/green ground, white and red taped together and black hot.



Edit-see

http://www.seymourduncan.com/support/schematics/schematics.php?schematic=color_codes

[rc2904]

For regular duncans like the duncan distortion I tried you are correct. But the duncan 'designed' detonator is reversed. It doesnt even have a bare because its wired into the black straight off of the baseplate. Other duncan designed ive seen follow the regular duncan wiring code so the detonator may be an oddball.

[jdr94]

Well Im not saying youre lying but this pic shows that bare and green have been put together, white and red taped with the black on its own

http://i11.photobucket.com/albums/a198/Meatschitts/GEAR/DetonatorPair02.jpg

[rc2904]

May be from a different year. My detonators are definately green/black reversed and have a brass colored baseplate instead of silver like that picture. I do have a different duncan designed that came from a kkv which has the traditional color scheme and has the silver colored baseplate like the picture of those detonators you linked.
Trying to move on from the pickups though. Any opinions on the shielding? Should I just leave the cavity like it is and try not grounding the shield? Should I sand off the shielding paint? I have aluminum tape if I need to reshield it but honestly I havent needed shielding in other guitars. I dont know if the RR3 is paticularly susceptible to emi or anything.

[jdr94]

You could reshield, but ive never had this issue w any rhoads ive owned( ps3-t, rr3, rhoads ex, rhoads pro) so I have no clue

[horns666]

Ed used to do major H, A, E, back in the day..hence his crazy innovations. Matt Bruck disclosed that so-called 'wax' is coats of Ed's semen. These are facts!

[rc2904]

So i got a multimeter and measured the resistance on the shielding paint. With the leads seperated by 1 inch of paint I get 1.5k ohms. I thought it should be somewhere under 100 ohms end to end. Will the shielding actually contribute to noise when it is that bad?

[84sups]

When I wired up my old mutt I reversed the connections to the jack and it was pretty bad. I honestly sounds like a bad ground if it's with other pickups from another guitar that was good.