• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join freeLog in
    Want zero display ads or expanded classifieds tools? Compare plans.

Fender TBX control...resistors

Hi all,

I have a question about the Fender TBX controls. The Fender Jazz Bass Special(s) I have feature the TBX controls. I'm restoring one that's missing the electronics and I purchased a couple of the genuine Fender TBX controls (which look like regular large stacked CTS pots but function just like the TBX on my basses). My question relates to the resistors, as the original 80s TBX controls on the basses (which are dime sized pots instead of large ones) have 2 resistors, while the new controls I purchased only come with 1. The 2 controls get wired (according to the diagrams) identical, except that the old ones have a 2nd resistor in parallel with the capacitor.

The wiring diagram I have for the Fender Duff McKagan signature also appears to have this 2nd resistor, but I haven't seen an actual one of those basses to confirm it. Is there something different that I don't know about when it comes to putting these on a bass instead of say, a strat guitar? The new ones from Fender only have 1 resistor that come with them and its the only one in their diagram for it. The control says for use in any passive guitar or bass.

Any idea what the difference is/would be with the 2nd resistor in parallel with the cap? I can probably go to radio shack and buy whatever resistor is "missing" from the new parts but I don't know if the new ones aren't supposed to have it or not.
 
I have the same problem... but my bass still hass the pots in them :)
So i did some research and found this; 0.22 Capacitor, 1st resistor (just the one that comes standard with the TBX Pot), 2nd resistor 4.7M ohm (± 5%). BTW, could you send me you're schematics? ([email protected]) I guess that's YAY for teamwork :D

Thanks in advance, Marko :)
 
The 500k vol pots are the original value, and the originals were later replaced with new 500k vol pots.

The original TBX had the smaller size pots, and I have since replaced the original with a newer TBX.

The newer TBX sounds close to the same to me, but has a smoother transition when adjusting the unit.

I'll see if I can get a scan of the schematic that came with the JBS when I bought it new in 1985.

(I don't know the TBX specs in the later Duff bass, maybe someone else could verify)
 
Last edited: