arley
Rookie Solder Flinger
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qtb mod
Oct 20, 2005 16:48:32 GMT -5
Post by arley on Oct 20, 2005 16:48:32 GMT -5
i'm trying to finish the qtb mod, and i have a few questions i need some help with. my pups are seymour duncans, 2 duckbuckers ( 3wire + foil shield) and a screamin demon (5wire+foil shield). sd states that the bare wire is a drain. currently the signal ground and the drains are connected. should i seperate the ground ( to ring terminal), and the drain? ( to control pot). i was unable to determine my scenerio from qtb mod. also, i would like to add a .033 cap in place of the .022 on my tbx tone control. do i need to change the value of the resistor also? thx in advance! arley
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qtb mod
Oct 21, 2005 2:16:50 GMT -5
Post by zjokka on Oct 21, 2005 2:16:50 GMT -5
aren't that all humbuckers - or single coil sized humbuckers? It would be good to star ground a humbucker guitar, but shielding is not really necessary - humbucker are by definition hum cancelling.
all grounds should go to ring terminal, leave nothing on the control pots.
if you have 500k pots, 0.033 will be a better choice, or even 0.047.
hope this gets ya started, Johan
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arley
Rookie Solder Flinger
Posts: 7
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qtb mod
Oct 21, 2005 10:21:25 GMT -5
Post by arley on Oct 21, 2005 10:21:25 GMT -5
thx johan, the qtb mod states to leave non signal carrying shield grounds soldered to pot or other shield ground point. i assumed the bare wire would be shield ground, since its in contact with the foil shield on the pup wires. the duckbuckers are single coil size humbuckers and are dead quiet after preforming the mod, but my full size humbucker is plagued with hum. is it possible i have it turned around in the pick guard? right now the humbuker is unusable in my opinion. especially for recording.
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qtb mod
Oct 21, 2005 13:14:35 GMT -5
Post by zjokka on Oct 21, 2005 13:14:35 GMT -5
hey arley,
listen. i'm no electronics expert, but i've done the mods (mods! let me come back to that) twice. both was on stratocasters with single coils. they were quiet allright. as far as i understand it, the shielding of the pickguard is only recommended for single coils. Singlecoil-sized or fullsized, humbuckers are by definition hum cancelling, and are so in as much as the two coils match resistance values. They don't need shielding as much
The other part of the QTB (mods!) is the stargrounding that says you should attach all grounds to the ring terminal on the 0,33 capacitator. Did you ground everything to that point?
I believe there's another one from the 5 on the SD you should ground...
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qtb mod
Oct 21, 2005 14:11:28 GMT -5
Post by UnklMickey on Oct 21, 2005 14:11:28 GMT -5
... i'm no electronics expert, but i've done the mods (mods! let me come back to that) twice... this should work out well 'cause i haven't done the mods even once, but i am somewhat of an electronics expert. bet between Johan's familiarity with the mod, and what i can reason out, we can help you a ton. i'd refer to those duckbuckers as 2wire + shield and the screamin demon as 4wire + shield. the bare one does, as you said, just connect to the shield. the standard SD color code for a HB is: - Bk = signal "hot"
- Rd and We soldered together = coil split
(if no coil split switch, these two are still connected together, but not to anything else.)
- Gn = signal ground
the orientation of the pickup in the pickguard makes absolutely no difference (unless it's magnet-up or sideways) so my guess is there is a wiring error for the screamin' demon unless you are doing a more complicated switching arrangement, this should take care of the hum. when all is right, demon should be about the same hum as the DBs, but YMMV. good luck, U.M.
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arley
Rookie Solder Flinger
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qtb mod
Oct 21, 2005 15:38:55 GMT -5
Post by arley on Oct 21, 2005 15:38:55 GMT -5
thx for all the info guys, i've gone over and over everything, i'm sure that demon is wired properly and yet still hums much worse than the other two. when you say hum cancelling, does that mean no hum at all? if so i would have to say my pup is faulty. in hind sight its been noisy since day one. i've gone to great lengths to prevent noise and hum and interference out of my home studio just to sabatoged by a pup. and this pup is top of the line, wax potted, shielded, shielded wireing, from the factory. anybody know how to tear apart a pup, and what to look for? anybody know what the pros do to rid there recordings from hum and noise? thx arley
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qtb mod
Oct 21, 2005 16:16:33 GMT -5
Post by UnklMickey on Oct 21, 2005 16:16:33 GMT -5
don't tear it apart yet!
disconnect it from the guitar and make some resistance measurements first.
measure between the Bk and the Rd-We connection. should be the same or near the same as Gn to Rd-We. (something like 5,000 ohms)
also measure between any of the above and shield. should be in the megohms or higher if not, determine which lead the resistance to shield is lowest. that will help in finding a short.
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arley
Rookie Solder Flinger
Posts: 7
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qtb mod
Oct 21, 2005 18:32:12 GMT -5
Post by arley on Oct 21, 2005 18:32:12 GMT -5
thx unk, i'll try that
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