Our gear is comparable. I have 4 ZMFs (Ori; Aeolus; VO; Caldera). I have 2 systems in the home office:
- One had the Wells Milo + Metrum Onyx
- The main system has the V281 + MHDT Labs Orchid.
I also own a recent vintage Audio GD R2R11 MK2 AIO that I use strictly as a DAC, and when it's driving the Milo, also as a preamp (comments about that below). All 3 of these NOS DACs work quite well with both amps.
If I had to pick just one DAC, though, it would be the Orchid. The tube in the Orchid is not a driver/preamp tube, but a buffer. That's a very light use of the tube's power; the whole point is for the tube's sound to "flavor" the DAC's output. I rolled those tubes a couple times, and when I found the right tube, it was so obviously better than any other that I stayed with it. The Orchid has a lovely sound, quite musical. Bass is excellent, too, though it hits a bit differently than the bass in the non-tube buffer DACs.
Comment about gain of the Milo: every Milo is different, not just "levels," but usually different volume pots, either stock, non-tapered analogue pot, or one of the non-tapered stepped pots Jeff has used. My first Milo had the former pot, and even with the switchable -13 dB attenuators Jeff installed in it, there was simply too much gain for me to use it with either the Orchid (3.0v output) or Onyx (2.5v output from SE jacks). That Milo was only really happy when driven by the AGD DAC in preamp mode w/volume set to 60%. That combo sounded very good.
I sold that one and got a 2nd Milo that has a logarithmic pot. It clicks when I turn it, but I suspect it's not a trad stepped pot w/resistor or reed relays. I think it's just cogged in some way to make the click (there are 100s of clicks in the full range of the pot--more than any stepped pot I ever heard of). Anyway, this logarithmic pot made a HUGE difference. I can use this Milo easily with any of the 3 DACs. It sounds great with all of them, and I can more easily hear the slight sonic differences between them (the Milo is quite revealing in its way).