The only thing we didn’t get was a long battery life, as that ended up being sacrificed for power instead. And power it has aplenty, presenting a wide and spacious sound through everything from low-impedance and low-sensitivity planers through to high-impedance HD-800s, with audio sourced from either a computer through its asyncronous USB input, or its second input, which at the time of purchase you have to choose either an iDevice-compatible USB socket or an optical digital input. While the former can be used with Apple’s devices, the latter can be used with anything that has optical digital output, including quite a few DAPs these days, such as the Astell&Kern series.
- The 4XL with a 4-pin XLR and large and small headphone sockets (the latter of which doubles as an optical digital output for USB passthrough — didn’t I tell you “everything and the kitchen sink!);
- The RSA, which puts an “RSA”-style balanced headphone socket in place of the 4-pin XLR (such as used by Ray Samuels Audio, ALO Audio and Cypher Labs);
- The original “Combo” which uses Neutrik Combo jacks which can either be used as regular headphone sockets or as a balanced headphone output;
- and the Pro version with regular male 3-pin XLR sockets for DAC/pre-amp use.