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Need help identifying pots for Ibanez TRB1 bass (1993)

Discussion in 'Pickups & Electronics [BG]' started by mviktorc, Jul 4, 2017.

  1. mviktorc


    Jul 4, 2017
    I'm a new bassist and new to the guitar repair world, so bear with me if this is an overly simple question: I would like to replace the three pots in my (P/J) Ibanez TRB1-CA (1993) bass. The pots appear to have been resoldered by the prior owner; and I can see "250K" on the tone pot; but beyond that, I am lost as to what exactly I need to obtain. Any recommendations are greatly appreciated.

    Attached Files:

  2. First of all, why?
    There must be a reason you want to replace them :wideyed:

    Are they scratchy?
    Do you think you can improve the timbre of the instrument with new potentiometers?

    If it's using 250k Ohm pots, you can increase the brightness by using 500k Ohm pots.

    There are two common "tapers" to choose from, audio & linear.

    I prefer linear for the volume potentiometers, but many manufacturers use audio for all of them, probably for simplicity of storing & ordering raw material.
    There are probably plenty of places where you can read up on the the differences between audio & linear taper. gOOgle is your friend

    For the treble cut potentiometer (or "tone pot") almost everyone uses audio taper, but then what's left is choosing an Ohms value.
    250k Ohm is standard, but if you want that extra brightness get a 500k Ohm.

    AllParts.com has pots, but you'll need to be careful that they fit into the holes & the body (of the pots) aren't too big. It looks like if you replaced them all with full-sized pots they'd interfere with the output jack.

    A lot of pots have a 3/8" bushing, and those smaller pots in yours are probably Metric, meaning the hole they need in the body will be smaller. You can always take one out & measure the diameter of the hole.
    Last edited: Jul 4, 2017
  3. mviktorc


    Jul 4, 2017
    Howdy, Killed_by_Death: Thanks much for that extended answer. While it is definitely a low-end bass, I love the action and playability of the thing (I swapped out the stock pups for SDs, and that added a bit of juice to it). In fact, it was this bass that got me into playing bass. However, the bridge pot is busted at this point; and I just figured that I would replace them all if I have to replace one. Again, the response is appreciated (particularly, the difference between linear and taper, which was new to me), and I will be checking out allparts.com.
    Killed_by_Death likes this.
  4. Trb1 is my first bass. I bought it new in 1993 and I still have it. Mine was made in Japan and i don't consider it a low end bass at all. The neck has never needed adjustment and the fretboard edges are as comfortable as my American standard fender basses. It's super light at 7lb 3.5oz. The stock pickups leave something to be desired but you've already addressed that.
    mviktorc likes this.
  5. mviktorc


    Jul 4, 2017

    Finished the project. It took me a few takes of assembling, hearing nothing, and then disassembling and regrouping. But the third time was the charm: 250k tapered pots; .047 Orange Drop cap on the tone knob; shielded all the cavities with wires to ground. And it did make a huge difference.

    Thanks again for the help!

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