I'll be very honest. One of my favorite sub-hobbies in the grand scheme of head-fi is auditioning and discovering giant-killing gear. To me it's pretty fun putting much less expensive gear up against bigger, fancier kits to see how well the David compares to the Goliath.
For those that like to skim, here's the TL;DR. The R2R 11 from AGD is a giant killer in every sense of the word. I can't think of a more versatile device for a computer based head-fier on a budget.
Instead of the normal breakdown - bass, :, treble, soundstage - I'm going to go through this review according to the pros and cons list above.
Value:
Unbeatable. For under $400, the R2R 11 gives you a very solid ladder DAC implementation that can play every format from redbook to native DSD, enough driving power for just about anything short of an HE-6 or K1000, multiple gain levels, and a top notch Amanero USB board. Enough said.
Sound Quality:
Let me put it like this. This little combo unit compete handily with separate dedicated DACs and amps that together totaled over $1600. Did it beat them around the board? Of course not. But let's just say that it definitely took some effort to pick apart the differences between the two rigs.
Overall the R2R is a smooth, fatigue-free listen that isn't rolled off or lacking in the detail department. For those who find the influx of Sabre chip-based DACs a little bright or abrasive, the flavor that this guy offers might be just your medicine. To me it's in the same vein as the Denafrips Ares and Schiit Bimby. Smooth, clean, and natural.
Driving power:
Like I said above, this little guy has enough juice to drive any dynamic, and almost any planar headphone with ease. I threw AKGs, Grados, and Senns at it and none of them presented a problem at all. Plenty of headroom all the way 'round!. It also bears mentioning that the 11's output impedance is friendly to any headphone and all but the most sensitive in-ears. Not to mention you can dial in the sensitivity/volume play using the different gain levels!
Versatility:
In addition to the aforementioned driving power, the 11 also has three different input options, AND can run signal to the headphone out, fixed, or variable LO.
Size:
There are plenty of other combo units that offer the complete feature set that the 11 does (although 99% at a higher price tag), but take up way more space on the desk or rack. This little guy has a footprint smaller than a piece of printer paper! If desktop space is limited, I can't think of any other combo units that can get you this far up the head-fi ladder in such small square footage!
Cons:
Not really any that I can think of. I suppose wait time on a new unit could be a con if you're not in China. I'm sure some purists will pick out flaws on the measurement sheet, or the fact that there's no LED or balanced outputs, but honestly at this price point, I think the 'pros' list far outweighs anything you could find on the 'cons' side!
So in conclusion... the newest entry-level combo unit from Mr. Kingwa is a home run for sure. You could certainly spend a lot more money and do a lot worse in this hobby. The R2R 11 get's two enthusiastic thumbs up from this head-fier!
PS - I certainly think that this is one of those pieces that could be moved into a larger, heavier case with a fancy OLED, a few more XLR ins/outs, and a bigger power supply, and then sold for $$$ and no one would be the wiser...
