Thank you alexc!
Prototyping is complete, and here is the final schematic. This is a variation of the james stack from Designing High-Fidelity Tube Preamps by Merlin Blencowe.
This sounds really nice. There are options to run thru the tone stage or bypass by using the 1/4” jacks.
With controls set on the tone stack 5 treb, 5 bass, 5 vol it is fairly flat and coincides with the bypassed level.
Running through the tone stage adds a touch of beef/tube-ness, so bypassing it is a really hard to beat clarity.
But having an option for treb, bass, sparkle boost, and volume is awesome.
With this tonestack you can also dial in a mid scoop around 1k or a mid boost when you max or min the treb/bass and adjust volume up or down.
I can make a youtube video demonstrating and post that.
Please correspond for a hi res scheme.
I put a lot of effort into biasing the DC-coupled cathode follower and calculating output impedance and miller capacitance for the next stage. These values were important in achieving the best tone stack performance, and may be subject to minor changes.
PS, working title “Gravity Bong”. This seems like a $1k+ studio tool, hehe

*EDIT SPARKLE BOOST CAP VALUE (on cathode of initial gain stage) 10nf. The 50volt tap comes at the first node.*