I see Fosi has just added the V3 with 48v power supply as a $77 optional add on to its
P3 tube buffer preamp ($64) Kickstarter Campaign. So $141 for both, probably shipping sometime in Sept. from China.
I also see Fosi has just released a desktop
Headphone Amp/Preamp, the SK01, for $80 or less with coupons or on Ali-Express. Featuring defeatable Bass/Mid/Treble tone controls, gain switch, and loudness contour. EDIT, I guess it is not a DAC.
Functionally the SK01
would be an almost perfect companion to the V3, if they had only made it V3 shaped with RCA pre-outs and inputs.
Perhaps they will release an audiophile V3 shaped version adding a sub output with fancy parts and replaceable op amps. That would be extremely popular as a V3 companion.