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Post by newey on Jun 29, 2013 9:10:56 GMT -5
With the assumption that you're using Seymour Duncan wiring colors, the switching looks fine. JohnH suggests (after extensive testing) to use a 150K resistor for the treble bleed circuit instead of 220K, but what you have will certainly work just fine.
I'm not sure what you're after with the dual-gang tone control. Is this supposed to give you a "mid gate" kind of thing? I'll let others weigh in on the efficacy of that, but I would think that the 220K resistor would really start to cut into your output with the tone control rolled down even a little.
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Post by JohnH on Jun 29, 2013 16:00:26 GMT -5
Im also puzzled by the tone control. What's intended there?
For the treble bleed, if the intention is to keep as close to ths full-volume tone as possible at refuced volume, I found that a resistor and cap in parallel are best , whereas the diagram has them in series. With a 500k pot, a 150k resistor and 1nF cap was found to be optimum. If the lower end of the volume range say 1 to 4 is more important than 5-9, then a smaller cap is slightly better, 0.82 or 0.68 nF. With a 250k pot, same cap but 120k resistor.
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kurik
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Post by kurik on Jun 29, 2013 19:58:49 GMT -5
The tone circuit is a TBX (250k on bottom and 1m on top) wired ala "Doc's Mod." Here is some of what he has to say about it (my electronics classes were over in '95 and I haven't used it much since so I won't attempt to analyze it myself):
"If you look at the stock TBX control internal schematic (not the simple physical hookup diagram from Fender) you will see that the 250k pot's resistance trace stops at midpoint of rotation. Beyond that the 250k element goes open-circuited. There is a temporary "wide open" at that point, until the 1megohm pot's trace picks up and starts adding total resistance to the series string. My 220k resistor substitutes for the now departed 250k resistance trace, so that the series string becomes seamless and the increasing rotation toward "10" adds 220k to whatever portion of the 1meg trace is picked off by the wiper. At "10" you have 1220k total resistance in series with the .02uf cap to ground. Almost "no-load"."
I'm looking to have all 3 humbuckers be as bright as possible and yet have the ability to roll off the treble substantially when desired. The comments about the treble bleed make some sense. Thanks for the input. Any further comments will likewise be much appreciated.
I studied electronics for 2 years at a community college and then immediately went to work swapping cards in PCs and promptly forgot everything I'd learned. So, I can mostly use a DMM and usually not grab the wrong end of the soldering iron, but that's about the extent of my skillz.
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Post by JohnH on Jun 29, 2013 20:54:03 GMT -5
You studied electronics for 1.75 years more than I did, and 15 years more recently!
I see now about the tone control. THere are a few different re-wirings of a TBX pot around the 'net. another one i saw had no load at 5, then treble cut one way and bass cut the other - thats the coolest ive seen. Im enjoying simple no-load pots with my humbuckers, the increment from 250k to infinite seems quite small. Definitely worth having, but not enough to want to split it up further so its fine as a small step.
Heres another watch-it/issue. You have both humbuckers wired the same - all good. the middle is shown as a single, and if thats the case then you may wish to figure out which way to wire the humbucker switching so that they humcancell with M when in single mode. And also check you will get in-phase combinations. But you also mentioned three humbuckers, in which case not an issue wrt humcancelling.
No matter what you have, you can always wire it up for best phase and humcancelling, but it may affect which wire colours go where. Before wiring up i would want to do a full set of tests to know about polarity and phase. Its easy to do - so let us know if you want to discuss this more, or if you have it sussed already.
John
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kurik
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Post by kurik on Jun 29, 2013 21:17:14 GMT -5
"You studied electronics for 1.75 years more than I did, and 15 years more recently!" Ok, I'll stop using that excuse, hehe.
The middle pup is a stacked humbucker wired in series. I made a note on the drawing, but was lazy and just tacked it on at the bottom. My bad. You're right though. If I can't get the sound I want out of the middle pup I was thinking I could add a simple coil cut, but then the polarity becomes an issue. I guess I should give it some thought.
This particular version of the TBX tone control was just the first one I found that seemed to make some sense. I'm not wedded to it though. I still have some parts on order so there is time yet for a little more education before the soldering iron gets hot.
I saw a picture of a treble bleed circuit that was parallel as you suggest, but instead of a resistor they were using a 250k trim pot. That might be the way to go, assuming there is room for one there.
Thanks again for the input!
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Post by JohnH on Jun 29, 2013 22:23:13 GMT -5
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