• Electric Repair

  7 Lug Tone Pot?

  Posted by Mike Kugler Kugler Guitars on April 14, 2025 at 3:38 pm

  I have a Fender Jazz Bass Special in. Looking to upgrade some caps and resistor per client.

  I found this “TBX”? tone pot inside. I don’t think I’ve encountered one with the additional lug on the back end. Any help as to if this is a TBX or similar and the functions of the pot?

  Thanks!

  

  Mike Kugler Kugler Guitars replied 1 day, 11 hours ago 2 Members · 2 Replies
• 2 Replies

• 

  Gerry Hayes Haze Guitars

  Administrator

  April 17, 2025 at 10:37 am

  Hey Mike

  Have never seen a TBX quite like this and I don’t remember seeing one of those ‘extra lug’ pots used in a guitar but this does make some sense.

  The extra lug on a pot like this is generally a centre tap — a connection right into the middle of the resistive track. So, between the extra lug and lug 1 will read half the total resistance and between the extra lug and lug 3 will also read half the total.

  The current TBX pots aren’t regular pots. Each of the stacked pots in the TBX is modified so that they only have half of their resistive track (one pot’s track covers 0-5 on the knob and the other pot covers between 5-10). My guess is that using the ‘tap’ lug on this pot allowed them to get a similar behaviour before they had tooled up for the current modified TBX.

  Like I say, I don’t think I’ve seen these extra-lug, tapped, pots in a guitar before but, now I think of it because they’re sometimes used in L/R balance controls and similar, it’s quite possible they’ve been used in something like active preamps or maybe even for blend.
  • 

    Mike Kugler Kugler Guitars

    Member

    April 17, 2025 at 11:51 am

    Thank you Gerry.

    That makes total sense once you break that down. For some reason my gut reaction was its a ground. But, obviously it is not.

    For followup, client is having an Auricap .047 cap & Kiwame 180k resistor installed. Apparently its a good upgrade for a more even swipe. 🤷

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