My thoughts on both the Audio GD and the SW1X:
Audio GD Master 7 Singularity ($2800 in 2018):
Up front, I was hesitant to purchase this DAC because of the ASR review but have some other audio friends who have one and told me that review is baloney and I am here to say I agree. This is a great DAC. Kingwas support is AMAZING, plus there are periodic updates to the firmware and flexibility to tune the DAC to your liking via the jumpers inside the DAC.
I used this link as a settings guide for the jumpers to put it in different modes:
Audio Dandy - How to enjoy High Resolution Audio
I placed the jumpers on the author's favorite position from the link and it was "good", but still not quite there. So, I set it to NOS and its WAY better. It provides more detail, so much warmer and almost no etch. Still some sibilance, but much less than the Altmann. Very engaging and pleasant to listen to, and I'm like tapping my foot and hand, moving along with the music. But I do agree with the author of that paper that in the NOS setting the music feels like it's a little bit behind the speakers. The Audio GD does a lot better than the Altmann but can sound a little thin in comparison to the SW1X, when putting them back-to-back.
I am certainly going to keep it for a long while as I think about saving up for an SW1X.
The SW1X Dac II Special with USB ( $5950)* just takes things a step further, it cuts down sibilance even more, although not 100%. What it does so well is make the music present! It often feels like the artist is closer than they have been before with other DACs. There is also this additional energy that gives the music more life. The reproduction is eerily good with the sound of the instruments, and it ups your ability to hear the mouth sounds and breaths that artists are making when recording. The music feels close and all around you much like it sounds at a concert in a good venue. This was especially prevalent with a good recording like Caroline Shaws
Let the Soil Play Its Simple Part
It did add a teeny bit of noise to the system though, nothing offensive, but not dead quiet, tubes is tubes I suppose.
I also got my GF to spend 45min listening to music with me and she was wowed with how the SW1X sounded. Which is saying something because its VERY hard for me to get her to sit and listen to music with me.
I also had the opportunity to demo the SW1X and AGD with Eddie at Eurotubes in his bar system and it was a bit different because of the space. He has a very nice bar system with a JJ 2a3 Power amp, a JJ pre running some Klipsch RF7's and we did direct USB from the computer to both units. The SW1X threw a wider sound-stage and created more space in between the music then the AGD. I would say, its wasn't quite as good as in my smaller home room, but this could have a lot to do with room dynamics. We both agreed that there is still some sibilance regardless of the track you listened too, but it really does a good job of bringing that analog sound to digital music. Price is still hard for us to wrap our arms around.
They both are ruthless with the recording, showing them for what they are, where bad/subpar recordings are noticeable!
All of this has me curious to try an Abbas to do a back-to-back comparison, but alas this is a hard thing to time right and would need buy an Abbas outright to do the comparisons, but from what I read there an many happy customers out there for the Abbas.
What I do know is you don't often see either of them (Abbas and Sw1X) used, so maybe there’s not a lot out there or maybe people really think they're that good.
That's my 2 cents after listening to both of them for about 15-20hrs in my room with this chain: Pi Streamer->Audiplilleo 2 with Pure Power ( Spdif) -.Erhard Audio Aretha Preamp ->Oliver Sayes SET45 ->Vintage Klipsch La Scalas
The age old questions persists, what is that next little bit worth? I do think the SW1X could be a final destination, where it would be so hard to wander from, but its also about $3150 more than the MSRP of the Audio GD. Only $2050 more if you don't want USB in the SW1X.
Oh, and I now see how DACs can drive one CRAZY! Yikes!
* ( Note that I was told by Slawa that the DAC II Special I was sent is older design about 1.5yrs old. He says their new design is better, more musical and more real)