That cool Joe, I also prefer a lower gain NOS preamp tube in my Tube Driver. I have the 3 knob Tube Works/BK Butler model like what Andy Timmons uses. Joe is 100% correct about the voilin tone. You need a cranked up Plexi style amp with the Tube Driver, Echoplex, reverb, and optional compressor. EJ use to use a TC Sustain in the old days. I love my Keeley Compressor to fill those duties. Also don't overlook the effects of a non true bypass wah on the signal path. I get a way better violin tone when my Vox wah is in my chain (really helps mellow the sound).
Suggested Tube Driver settings: Volume 9-10 o'clock, all eq knobs to "0", and gain to taste. My gain settings are between 11 o'clock and noon. Don't forget the 12AT7 or 12AU7 tubes. They are a lot less harsh and the gain is much more controllable with these tamer tubes. Good luck.
'67 and '74 Fender Twin Reverbs, '74 Marshall 1987 lead mkII, Metro Superlead 100. Pedals from TC Electronic, Ibanez, Dunlop, BK Butler, Electro-Harmonix, Fulltone, Maestro/Gibson, Loopmaster switching, VoodooLab, Boss. Gibson and Fender guitars, Dimarzio pickups.