So, the tone selection toggle switch selects 1 of 3:
(1) the cap w/pot circuit
(2) the 2 caps w/resistor circuit
(3) neither
What happens with (2) the 2 caps w/resistor circuit?
Thanks!

http://www.rickenbacker.com/pdfs/19506.pdf

I have the schematic in my post above...

Anyone? In this schematic, what does the tone circuit composed of C1, C2, & R1 do to the tone? Thanks!

http://www.rickenbacker.com/pdfs/19506.pdf

The "(2) the 2 caps w/resistor circuit" cuts both low-end and high-end thereby making the guitar more midrange sounding. It's very much like having only the bridge pickup on of a standard RIC with a cap in its line, to cut a fixed amount of low-end, and then rolling off a fixed amount of high-end with the tone pot for the bridge pickup.

Remember that this wiring was also used on the 50's Combo 900 and 1000 guitars, when electric bass was also a relatively new instrument, and presented its own recording issues. Expanding on what the wiring does, the 3rd position may have been envisioned as a pre-set to double the bass on a recording, or even serve as the bass when there was no bass player, much the same as the 3rd position on the original Esquire wiring was designed to do the same thing with its similar capacitor/resistor network. In Nashville, this was called the "tic-tac" bass, for its articulated but mellow tone with a pick. The reason I say this is because: 1) two of the wiring positions are the same as the original Esquire wiring, bypassed tone and conventional volume-tone, and 2) the well-known marketing arrangements in the early days between Fender and Radio-Tel.

But also, since this wiring does cut bass as well as treble, it could have also been a "jazz" setting, or a rhythm guitar setting. Is there any marketing literature out there, internal development memoranda, or even anecdotal evidence as to the purpose of the wiring? The above paragraph is simply my extrapolated speculations.

Interesting, iiipopes. I'll look around to see what I can find.