Strat TBX circuit.

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by Curt, Jul 20, 2004.


  1. Curt

    Curt Member

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    Has anyone installed a TBX pot in your strat? If so, what did you think?
     
  2. John Phillips

    John Phillips Member

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    I take them out of any Strat or Tele I find them in.

    If it's mine of course - but I'll recommend it for anyone else too. I can't stand them - tone-killing, plastic-sounding piece of marketing BS.

    They were billed as giving 'more presence and sparkle' when turned right up, or some such rubbish. In fact they do nothing of the sort - they just make you think you're getting more brightness at the top end by artificially strangling the tone at the detent position.

    There's an 82K resistor in parallel with the lower part of the dual pot. Above the detent, the resistor and the tone cap are progressively taken out by a 1Meg pot; below, the resistor works in parallel with a normal 250K pot and a .022uF cap.

    IMO there's no position on the whole control that sounds really 'right' - anything below the notch is honky and lacks depth, and up full is thin and harsh - and there doesn't seem to be a happy medium.

    I think the best thing to do is remove it and replace with a standard 250K tone control with either a .022 or .047 cap. If you do want an ultra-bright sound, the newer 'Delta Tone' no-load pot (which removes the tone network from the circuit entirely when the knob is at 10) sounds much better IMO.

    [/rant]

    There... I feel better now.

    :)

    There are actually a few ways of modding the TBX circuit to make it sound better too - all of which involve removing the 82K resistor - but considering they have an irritating habit of going scratchy at the detent position, I think you're just better off without them...
     
  3. Curt

    Curt Member

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    John,

    Let me get this straight.....are you saying that you DON'T like the TBX circuit? Seriously, thanks for your opinion. I think I'll pass on the TBX.
     
  4. somedude

    somedude Member

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    I have them on mine.

    Mine has a 3.7meg resistor in parallel with the .022uF cap on the one pot, and an 82kohm resistor on the bottom.

    Below five it works just like a normal pot, above five it adds brightness (I'm told it does this by altering the resonnant peak of the pickup).

    Mine's 15 years old and still isn't scratchy.

    The only time I ever use it above five is occasionally I'll use it on the bridge humbucker to punch through high gain a little better. I never use it on the neck singles.
     
  5. Old Fuzzface

    Old Fuzzface Member

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    I'm with John - I thought it was dreadful.

    I put the Delta tone on mine. So I can have the tone control on the bridge pickup but still get the "vintage" Strat bridge tone, i.e. with no tone control in circuit, if I want it.

    Much better.
     
  6. poipounder57

    poipounder57 Member

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  7. gregc

    gregc Member

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    I like em with the new noiseless Strat pickups. I prefer vintage style Strats without them.
    gregc
     
  8. TheEnemyWithin

    TheEnemyWithin Member

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    Sorry to bump a really old thread, but a Google search on this topic led me here. If you guys frown upon bumping old threads, well, I'll find that out soon enough. :cool:

    All these years I could never figure out why my '91 American Std. Strat had this brittle and tinny sound to it, no matter what amp I was plugged into or what pickups were installed (I currently have a Duncan JB Jr. in the bridge and Suhr V60LPs in the mid and neck). I recently wondered if the TBX tone circuit could be the culprit, so I did a little digging.

    After reading this thread, and seeing the TBX described as a "tone-killing, plastic-sounding piece of marketing BS," I was motivated to order a Fender 250k no load pot (.022 cap included) and will replace the TBX with it.

    I'm no expert on Strat wiring, so my question is, though the TBX pot controls the bridge and middle pickups, are all three pickups affected by the TBX circuit? For sure, all three pickups on my Strat have that layer of brittle over them.
     
  9. mc5nrg

    mc5nrg Supporting Member

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    I don't frown on anything that brings John Phillip's posts back to my attention.
     
  10. walterw

    walterw Gold Supporting Member

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    agreed. before bothering with all that, try turning that TBX down a little, maybe even to the halfway "notch" in its travel, to get a mellower tone.

    but y'know, ol' john has a point. you never get the classic tone of a 250k pot on "10", you just get the brighter unloaded tone up high, and an overly darkened tone at the notch. IMO, the "no-load" has the same issue, either it's out of the circuit (bright) or below 250k (dark).

    most hep cats these days just put a regular 250k pot in, but disconnect it from the middle pickup, leaving it attached to the bridge pickup; that way, the M+B tone has one tone pot loading it like it should, and the bridge also has the tone pot loading it, making the bridge less brittle and more in line with the rest of the guitar. this trick also takes the extra load off of the M+N setting (since it's only getting one tone pot instead of two), making it also more in line with the rest of the guitar.

    search "jimmie vaughan mod".
     
  11. Hugo Da Rosa

    Hugo Da Rosa Silver Supporting Member

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    John Phillips may be a very well respected man on this board, but I don't agree with him on this argument. I have this put into my 62RI strat and it sounds nothing like plastic. If anything, the sound I am getting is an added bass response and just a touch more treble, with the mids slightly scooped out. I'm not saying it sounds as good as how Fender may have marketed them to be, but it's a sound that I like and don't see the connection in how it sounds like "plastic".

    The TBX circuit can be used independently or can be shared among all 3 pickups. The wiring diagram (I believe) shows you how to wire it to one pickup. But if you want it to effect more pickups, just jumper the lugs on your pickup selector switch.

    I can't say exactly if the TBX is the cause for the brittle and tiny sound you are getting out of your pickups. Are you experiencing this when you select a certain pickup or if you are in the 2 and 4 positions? If it's in the 2 and 4 positions, then your pickups are out of phase. If not, then it can be an array of possible problems...but naturally, I don't see that being the TBX's problem unless it's a faulty pot.
     
  12. jbd3

    jbd3 Please Don't Sell Me Any More Gear Silver Supporting Member

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    I love late 80's/early 90's Strats, but I've generally taken the TBX tone knob out, never been wild about it. I've got a 91 Strat Plus in the shop now, with the red Lace Sensor at the bridge, and I think blue and gold in the other two spots. I'm keeping the Lace Sensors in (don't yell at me!), but I was wondering if anyone had a suggestion for a replacement for the TBX knob. I'll probably stick with a 250K pot, but I'm not sure about a resistor value. I only use the red p'up at the bridge for high gain playing by the way, since it sounds like a humbucker; I never use the bridge p'up clean. Thanks in advance for the advice!
     
  13. walterw

    walterw Gold Supporting Member

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    hey, laces have an annoying habit of actually sounding pretty good in context.

    what resistor? with a normal tone pot, there is no resistor.

    if you mean capacitor, try .02uF for hot humbucker-types and .05 for vintage fender pickups.
     
  14. TheEnemyWithin

    TheEnemyWithin Member

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    I've tried that. I usually keep that pot right at the notch at 5, only because, to my ears, anything above or below is unusable.

    The no load pot is billed as a normal 250k pot from 0-9, with 10 being a simple bypass switch which takes the pot out of the circuit. You're saying, on 9, that pot doesn't behave like a normal pot would on 10?

    The problem is there with all three pickups, all five combinations. That's why I asked if the whole curcuit is affected by the TBX, because even the neck pup has that plastic sound. It sounded that way when I had the stock Fender pups in there, as well as other previous pickup experiments. The TBX is the only thing in that guitar that is "unconventional," so for the sake of experiment, I'll remove it and see what happens. I never used it in the way Fender wanted me to anyway -- never kept it set past 5 -- so no harm done, really.

    Thanks for all the help so far, guys. :beer
     
  15. Bob V

    Bob V Member

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    I fouind the TBX didn't do much of anything from 10 to 5 and then below 5 it seems to take away all the recognizeable single coil tones, so I prefer the versatility of a regular tone control compared to the TBX gizmo. Also there are situations where a full-pass tone pot (Delta-tone) is very useful. Rob DiStefano posted a photo tutorial (here or on tdpri, can't recall exactly) on how to scrape the carbon path from the pot to convert a regular one to a full-pass/no-load tone pot and it's pretty easy.
     
  16. jspax7

    jspax7 Member

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    On my Strat Ultra, all 3 pickups are affected by the TBX. I used to like it until I put Dimarzio Area's in another Strat with a 250k tone pot on the bridge pickup.
     
  17. jbd3

    jbd3 Please Don't Sell Me Any More Gear Silver Supporting Member

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    I did mean capacitor, sorry about that. This has the red Lace at the bridge, so it sounds like I'd want .02uF?
     
  18. walterw

    walterw Gold Supporting Member

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    pretty sure that a no-load on "9" would be like a regular 250k on "9".

    on stock american standards, the tbx only affected the middle and bridge pickups. (of course, if you're set to N+M, then both tone pots will affect that setting.)

    i think all this craziness was fender's attempt to "have its cake and eat it too", in that they wanted to keep the original strat sound of the unloaded bridge pickup while still having the option of turning the tone down on it too if the player wanted, and to do this without added switches or knobs.

    i think these days most players who know the difference prefer the sound of a strat bridge that's more like the rest of the guitar, and so opt for a regular tone pot on that pickup.

    probably the best interpretation of this idea is the stock suhr wiring, which uses a 5-way superswitch to put the first tone pot on all settings except the bridge by itself, then uses the second tone pot just for that setting. (the superswitch is necessary to prevent both tone pots from loading down the crucial M+B setting). every setting on the suhr thus has exactly one tone pot loading it, and so sounds sweet and consistent all the way from neck to bridge.
     
  19. buchla300

    buchla300 Member

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    I liked the TBX setup in my Esprit Elite. Sounded excellent.
     
  20. buchla300

    buchla300 Member

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    Just an addition. Just got a Buddy Guy strat and am LOVING the TBX in it. Lace Sensors and TBX for me is a great setup. Perhaps not what most expect and I think people are just not understanding the pups. This strat is one of the nicest sounding I've heard.
     

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