Delta-tone is Fender's marketing label for a no-load or full-pass pot used for a tone control. When you turn the tone knob up to 10, the wiper disconnects, and you no longer have any path to ground through the tone cap, and the tone is a little brighter as if there were no tone control at all. This is a great solution for people who like the vintage wiring on a strat for the wide-open bridge pickup, but still want the option of rolling back the tone control. There's a thread here (by Rob C IRRC) on how to modify a normal pot to have that function. Can't be done with a volume control (unless you have a separate switch) but it's a great idea for the tone control.
TBX is a stacked pot with a center detent, two capacitors, and IRRC, a resistor. It's another option for a tone control. My subjective take on how it behaves is that between 10 and 5 (the detent) it doesn't do much at all, and betwee 5 and 0 it progressively rolls off any of the sparkle that identifies the instrument as a single-coil Fender guitar. It's used on the Eric Clapton models along with an active midrange boost.
Greasbucket is a tone control used on the Highway One models, where there are two different caps and a resistor. It behaves as if you have switched from one value cap to another as you roll back the tone control, taking off more of a slightly narrower band of frequencies. As you first turn down the tone knob, it rolls off a small amount of a pretty good band of trebles (highs and high-mids, lets call it). Then as you roll back further, it's taking out a lot but only the highest frequencies (just the highs, leaving the high-mids). Their marketing copy at the time indicated it was friendlier for high-gain setups. I suppose it's aimed at leaving a little more treble in the mix for people who use mid-scouped modern amp.
Delta tone is great, but TBX and Greasebucket are solutions to a problem that didn't exist.
The last variant of popular Fender wiring features would be the "S-1 switching" scheme where you have a pushbutton inside the skirt of the knob, to activate series/parallell wiring options (again, it's something we already thought of with the four-way switch on a tele).
"Why don't you just make 10 louder, and make 10 be the top number, and make that a little louder?"
Last edited by Vizcaster; January 15th, 2013 at 07:00 PM.