TBX tone control wiring help

Discussion in 'Tonefreaks' started by NylesR, Nov 2, 2017.

  1. NylesR

    NylesR Junior Member

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    Midtown. One of the things I added was a Varitone Switch, I really love this guitar and its one of my all time favorites. But I'm always hunting for ways to do things different and hopefully better I would like to add TBX Tone pots to my current tone controls. I currently have this wired 50's Les Paul style with a single 3 way toggle switch. I to know if I can replace my tone pots with the TBX ones and if anyone could help me figure out schematic for it. Any takers? Thanks! Also if this is a bad idea our will not work please help me understand why! :)[​IMG]
     
  2. Juan Wayne

    Juan Wayne Senior Member

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    This would be the schematic for the TBX alone:

    [​IMG]

    I tried it on a guitar with LP-style controls, no Varitone though, and it works great for that guitar.

    What I did is basically keep the volume/switch circuit as usual, and remove the tone controls. This way, you're still sending each pickup to a volume pot, then each volume goes to the switch, then straight to the output, or in your case, the Varitone. Now you have two free pots to work with, one of which will still work as a treble cut, and the other you'll have to mess with a bit so it adjusts to the schematic and make it a bass cut.

    The TBX itself would go right before the output (on in your case, right before the Varitone), acting as a master, two-band tone control. Where the schematic says "from switch", you hook up the output of the switch, and where it says "to volume", you send to the Varitone. Keep in mind this schematic is intended for a Strat, which usually goes through tone first and then volume, so that's why the schematic assumes you'd go there next.

    As for the volume pot values, 250k would be what you'd see on a strat, but I used the regular 500k you'd see on a LP which is what I already had, and so should you I guess. The 1M on the bass side of things is debatable. 500k worked fine for me, which I used because again, it's what I already had there to begin with, but 1M might give you more working range and a better taper. You can tinker with the cap value on this part, so it's not a big deal, but I'll admit the taper response in my situation would be better with the suggested 1M pot and maybe 4.7nF, instead of the 2.2nF cap I used. I don't care that much and mostly stay on 0 or 10, so I'll probably leave it as that.

    Now, is it a bad idea? I'd say not, it's a circuit that's certainly worth trying, but on a guitar that already has a Varitone it looks like a bit too much. The idea of the Bass part of the circuit is to get rid of some excess bass, which is why I implemented it on this particular guitar; it tended to get too loaded on the bass side regardless of pickups and everything else. The Varitone already gives you some thinner sounds, so personally I'd try the TBX on something with less controls already mounted, and where it can have a clearer purpose, but ultimately it's your choice and it'll be a fun experiment independently of the platform you choose.
     
  3. NylesR

    NylesR Junior Member

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    Thank you so much for your reply dffdff.
    I have a the TBX tone control on my Fender Custom Shop Strat with the Clapton mid boost and its the most amazing sounding guitar I've ever played and the versatility is to die for and the only reason I wanted to put the TBX in my Midtown. The Varitone switch is cool but I find that 4 of the 6 switch positions on it are almost completely useless, and I've seen a 12 way rotary switch on eBay from kellingsound that send like it could have some very useful settings. I may just disconnect the Varitone and see how it does with just the TBX in it.
    Once the TBX pots arrive today I'm going to see what I can get done, seems fairly straightforward but I might reach out if I have any issues. Again thanks for taking time to reply to my question I appreciate it!
     
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  4. Juan Wayne

    Juan Wayne Senior Member

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    No problem. That's what we're here for. Cheers!
     
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  5. NylesR

    NylesR Junior Member

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    Okay so, what do I do with my existing capacitors? Do you still run each from the volume to the new TBX pot? Also did you use the resistors the TBX came with?
     
  6. Juan Wayne

    Juan Wayne Senior Member

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    In my case, the one on the treble control remained in place, because that part of the TBX control, at least on the version I posted up there, works exactly as a regular tone control. I chose the bridge pickup tone for this because I associate it with treble already, but now it'll have an effect over the total signal instead of only one pickup, just like a master tone.

    The other capacitor, the one on the neck tone control, one had to go because the bass part of the TBX works differently to a regular tone control. I used the neck tone control for this part, but I had to get a new capacitor, 2.2nF in my case with the 500k pot I already had.

    Nope, I go straight to the switch, and after the switch, instead of going to the output jack, I pass the signal through the TBX on the way to the output. This makes the signal path like this: individual pickups--> individual volumes --> 3-way selector switch --> TBX --> output.

    Maybe we're talking different things here. I didn't get a kit, I went from scratch, but I didn't need any resistors either. The only resistors on that schematic are the pots, for which as I said, I used the ones already in the guitar.

    Are you actually taking the TBX out of another guitar? Did you get a pre-wired kit?
     
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  7. Dilver

    Dilver Senior Member

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    There’s an old guitar player magazine article about the TBX - it was originally designed to go into an active circuit. Do a Google search and I’m sure you’ll find it. Maybe you’re already familiar with it and knew that already, but thought I’d give the heads up since wiring a semi hollow is a big pain in the ass.
     
  8. NylesR

    NylesR Junior Member

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    This helped me alot
    Although I wired the TBX the way it said on the manual instead of with the bass cut and treble cut like the pic you shared. Fenders definition for the TBX is after 5 on the knob/detent it increases treble and presence. And that was exactly what I was looking for. I'll admit it took a little messing with to get it to work but I've got it in and it sounds great.
    It did come with a 82k resistor and I just used my .022uF Bumblebee caps instead of the ones it came with.
    What would be the advantage to using the modded TBX VS the original?

    I was aware of that and I'm pretty sure I read the article your referring to. Thanks
    And yeah it was a pain in the butt, but I'm sure the back of the midtown has more accessibility than most other Gibby hollow bodies. Thanks!
     
  9. Juan Wayne

    Juan Wayne Senior Member

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    Oh, I get it, it's "the other" circuit. I might have confused them. Maybe that's why the circuit I was referring to is also called the PTB, so they don't get mixed by dumbasses like myself. Yours would be this one then:

    [​IMG]

    Or on the Clapton version :

    [​IMG]

    Nevermind, I'm a boob, I sort of should have figured it out when you mentioned the Clapton boost on a Strat, haha.
     
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  10. NylesR

    NylesR Junior Member

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    @dffdff any idea on how I could add a DPDT switch to my Clapton Strat to allow for running the positions #2 & #4 in parallel and series? :)
     

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