The J2/J2S has received perhaps the most chatter at the HeadFi.org forums, as well as in the comments of various YouTube videos. The original J2 with optional AK4493 and Ti OPA1656 sounded neutral and a bit richer than the slightly more clinical ES9026PRO option, although the soundstage in either was somewhat 2D. Then again, this was a $250 setup.
The J2S AK4499EX + Sparkos SS3602 changed that dramatically, with bigger soundstage, better punch and dynamics. Everything here I run on a Panamax MR4300 conditioner, but several reported a step up using an LPS, so I bought an from Ali Express after numerous others had taken this route with solid results (
New 50W HiFi Ultra-low Noise DC Linear Power Supply 12V 3A Audio Amplifier LPS PSU With Blue Display). I have been pleased with this device and bought a second for another DAC. Some reported good results with the iFi Power X, although it is still a SMPS (but with good filtering) and more expensive. In any case, Geshelli doesn't warranty use with a different power supply, but no one has reported any issues, just good results. I use mostly USB as Geshelli's Amanero platform is dead quiet and excellent overall, although I noticed an audible improvement using an
Oyaide NEO USB Class A Rev2 Cable that was suggested to me, and which I tried with initial skepticism.
I have now evaluated and reviewed both Burson V7 Vivid and V7 Classic, as well as have many hours with the giant Sparkos SS2590. The V7C I find neutral and natural with a touch of richness and a great "all arounder." The V7V is indeed vivid, sounding more clinical and airy with enhanced separation. Both present a deep soundstage with lush texture in the center image, and which to use is a matter of system synergy and individual taste. The SS2590 has a rich, natural sound that is not quiet as deep up front, but is noticeably wider with enhanced lateral separation. While these differences are audible to the headphone crowd, they become even more apparent with a resolving speaker system with excellent imaging capability and enjoys good room placement. As far as delta-sigma platforms, I might venture to say this is about as good as it gets, and does so in the mid $700 range.
Geshelli's forthcoming J3 PRO retains the AK4499EX, but features a redesigned board that allows using the large SS2590s on all three sockets with the aid of adapters or extenders, a newer Amanero USB revision, an upgraded power supply, and a more user friendly input switching provision - all clearly in response to consumer feedback.
Also forthcoming is the
Geshelli DAYZEE, which breaks things out further, having dual AK4499EX chipsets (one for each channel), uses 8 (single) op amps, with (8) SS2590s being an option, and offers expanded connectivity. I don't know how little or great the sonic benefit, but this price point (~$1300) puts it squarely in the territory of R2R DACs, such as the highly regarded
Holo Audio Cyan 2.
Anyway, this is my experience and assessments in a nutshell.