Discrete R2r With Tube Output

LTA has a new one out getting good reviews.  $3,950.00

Aero - Digital-to-Analog Converter (DAC) by Linear Tube Audio

on another note why do you think chip based R2R's are inferior? to me they are more accurate as the resistors on the chip are better matched, wont drift out of spec as fast and do the same thing as a string of outboard resistors. chip based R2R's are not digital in anyway just a bunch of resistors on a chip apposed to laid out separately. well that's my understanding of them from my research. 

the aqua hifi lascala would do it

https://6moons.com/audioreviews2/aqua/2.html

pure r2rdesign

plays high resolution files

incredible analog stage

modular and upgradable

Dave and Troy

audio Intellect NJ

aqua hifi dealer

I have the Lab 12 DAC 1 Ref.   It really sounds good.  Something that should be auditioned or have an easy return policy.   I listened to a few DACs below , at , and above its price.   Loved its sound and can live without DSD and fixed output. Which I prefer on a source anyway. Not for everyone but a really nice sounding DAC. 
 

Maybe DSD is why he wants a FPGA type DAC….

The Wells Audio Cypher Dac is fantastic and uses the latest Sabre pro dac chips.

good luck on your search.