The Lumin Leedh volume control is almost perfect. The best control I have heard on a DAC or streamer. I did a shootout with my Benchmark LA4 preamp vs the Lumin X1.
The volume control on the LA4 is hard to beat by any gear. The Leedh matched it sonically until the very lowest volume. At that low range the Leedh no longer had consistent adjustments of the volume. Nitpicking. the Leedh is the only DAC I would use direct to amp if I were not to use the LA4.
I used ROON with the Lumin. I never had an issue with the volume. I used the streamer to stream into the Lumin X1 DAC (with fixed ROON volume) and also streamed out to via the Lumin SPDIF to control a PeachTree GAN1. The GAN1 has no volume control so I used the Leedh. I forgot if I also streamed to the GAN1 using variable ROON volume. Too many Lumin settings to remember now.