Hello! The V2 (non-plus, non-infinity version) prototype was a definite step-up over the already good V1, IMO. I returned that unit but got to spend time with it in my home over a few weeks of comparing. At first, the V1 and V2 were both good but with some differences- different flavors. After acclimating to the V2 though, it just seemed more engaging, euphonic, and resolving with more top end extension plus a more enveloping headstage when I would go back to the V1.
Based on V2 prototype making the V1s seem a touch "dry", I figured that I could replace all of my GO V1s with one V2+ Infinity and no longer need an Apricorn cable or external battery chained, taking up all kinds of room. (Not as portable when everything is chunked together with cables for maximum performance.) I ordered a V2+ Infinity from Indiegogo.
I have already sold my V1 450 & 720. I think I am keeping a V1 1000 (already bought and sold it once) just for use with my low output laptop and movies with Philips Fidelio X1. V1 is nice and small and can drive the X1 loud enough for the Out Of Your Head DSP software and movie watching comfortably with my 11" laptop. The bassy X1 phones like to rumble with movies so it's a fun rig.
At the SF Meet, I just picked up a loaner/beta version of the V2+ Infinity and haven't had much time to try it yet...but I will be trying it against the GO V1 1000 that I have to see if I hear all of the same improvements that I heard with the V2 prototype. Glad a few people did try the V2+ beta at the meet and they also found it to sound good. You can comb through some SF meet impressions if you want to see them.
A few things different from the V2 non-plus version that I can see so far: There is an on/off switch with LED indicator that also seems to communicate the charge level when using the micro-USB charging input jack. A
separate micro-USB input is near the two 3.5mm SE & Balanced outputs for taking the digital signal into the device. The 3.5mm jack nearest the micro-USB input is the TRRS jack which is balanced. The other 3.5mm jack is a single ended female TRS plug jack. The V2+ basically runs two separate full amplifiers, one for each channel...to reduce cross-talk amongst other things.
You can get balanced cables for your phones or you can get adapters if you want to try the TRRS balanced jack with your phones. It is not quite as simple as getting an adapter on Amazon, though. I started looking and many cheap 3.5mm TRS female to TRRS male adapters are for voice headset compatibility and won't work in this application. I ended up getting referred to Mimic Cables for being able to make any kind of adapter combo here (thank you, zerodeefex). I will be ordering a 3.5mm TRS to 3.5mm TRRS & a 6.25 TRS (metric way of saying 1/4") to 3.5mm TRRS and that will cover all of my phones with the V2+ and any of the balanced DAPs that I have in the future (won't need to recable everything). Without any manual, I have also figured out the gain button and LED. Blue is for IEMs, Magenta/Hot Pink is for the medium gain and Red is for high gain. There are also 4 white LEDs to mark sample rate or DSD, with another button and what seems to be 3 different digital filter options. Suppose there is FRM, TCM, and another to choose from (Blue/Green/Red).
As for the chassis, I am still getting used to the 3D printed prototype chassis over the aluminum. Many commented on the heat with V1 and worrying about how hot the aluminum got. Even building heatsinks. I
never felt in any danger of burns or melting things with my V1s even when outright grabbing them wondering because I would read worrisome comments. I suspect some people will be in the "3D is lighter/cooler" camp and some will like the aluminum V1 style chassis better for how solid they feel. If it works and it sounds better, I am going to go with that unit- metal or plastic. I kind of want to try to design an iPhone case that incorporates the V2+ anyway...
Another thing I'll share is that while I did enjoy the GO V1 SE that I had on loan from another HF'er, I found it just a little more refined and slightly better resolving than the regular V1 450 with the 450 being a little more "punchy" overall. To me, the "regular" V2 bests the V1 SE easily and is a bigger jump than V1 to V1 SE. Again, nobody needs to throw out any V1s. They are really good. It is just that there is a noticeable amount of difference in sound that I heard and I am reporting to you guys.
I'll keep updating as I can and hopefully my portable and desktop rigs are in good enough shape now that I will find myself studying up on music way more than gear. The gear is fun though- we keep getting more great-sounding choices...
EDIT (9/8/2015): Now from what I understand, one can use an adapter for a balanced cable to balanced TRRS plug but
not from a single-ended cable to a balanced TRRS plug. I changed my order with Mimic Cables.
I also now have a new 4-pin XLR balanced Audeze cable and an adapter that I can use with my HD800 4-pin XLR balanced cable as well:
