Pros: Small, Good amount of power, Great build quality, Natural tone
Cons: a bit dull sounding, Can't drive planar dynamic headphones to full potential, Noise floor heard on high gain around 2-3 o'clock
I don't want to ramble too much in this review, but I want to give a slightly counter perspective to the majority of reviews for the soloist sl. I used it with a schiit bifrost uber using the usb input, and with my audeze lcd 2 headphones as well as my denon d5000 headphones.
So the first couple days of use the sound was great, basically sounded just like most of the good reviews it has gotten. If you want to know what that sound is like then just read those other reviews because I want to speak about what happened after a couple days. Starting on the third day of use (and by third day I really do mean like 24+ hours of total use by that point) the sound started to lose a little edge, and little liveliness, a little grip. I gave it a few more days, tried every usb port, tried the optical port, switched headphones, used different songs/media players, but the sound remained consistent. It was subtle at first, but it just felt like your brain was having a hard time trying to latch onto the music, if that makes sense? the edge was gone, it always felt like something was missing in the sound, as if it was blurred over slightly or dulled. The bass was still great, the mids were still great, and the treble was still properly detailed, but as a whole the tone seemed to just dull the edges too much, which made the sound feel much less dynamic than it should, and after a while it just hurt my brain because it was being teased with details that just would not appear. The final straw for me to sell it though was the fact that it just did not provide enough power for the lcd 2 (the late 2013 pre-fazor version). Even on high gain I had to put the volume around 2 o'clock to hear the whole frequency range properly, but it always ended up being too loud after a while, but sounding as if it was too quiet. Like it would be too loud for your ears, but you kept making it louder because it seemed like it was missing aspects of the sound. Like the bass was good, but it obviously felt like it needed more power behind it, and the mids were great, that never seemed wrong, and the treble just sounded dull and lacked some detail. It just felt like if there was a bit more power, then I could keep the volume lower while having the sound be properly filled out. Compared to the soloist sl where it definitely felt like it was struggling to get the lcd 2 sounding right. With my denon's it had the proper amount of power, since they are very sensitive headphones, but that dulled sound made the denons pretty bad in the mids. See the denon d5000 already has a slight v curve frequency response, but the burson just made that v-curve even more v shaped. bass was stronger and tighter, treble was brighter, but the mids were too recessed. The lcd 2 sounded a bit better simply because it has a much more linear frequency response to this slight mid recession doesn't impact them nearly as much, but the dulled sound definitely does. On top of all this, the neutral/natural tone of the soloist sl just makes the dulled sound even worse because now it was lacking solidity and fullness, just brighter and dulled. it's a strange combination, but that's its sound signature no matter what you plug them into, or plug into them. Some people like that sound signature, their ears just enjoy that kind of thing, but for me I just really did not like it at all. I am looking at the violectric amps as my choice instead. Also to give some proper information about the soloist sl out there about its power output, it puts out about 650mW into 50 ohms. The 2 watt rating they advertise so much is only at 16 ohms, even my denons which are at 25 ohms only get close to a watt if using high gain, which is a lot for them, but 650 mW for the lcd 2 is only just barely enough to make them listenable and sound good, but very quickly you will feel like it just isn't enough.
So I will advise to definitely listen to a burson product first before you buy, this is not a company that makes products that you can safely buy blindly and enjoy. On youtube there is a guy whose channel name is headphoneaddictdotcom and he also agrees with me on this burson sound signature annoyance when he used a burson conductor for a few months. He also preferred violectric amps or just something more along those lines of sound signature. I have similar tastes to him, as in we like the audeze house sound, pre-fazors, denon dxxxx line, fuller and thicker sounding amps, neutral dacs, etc. If you feel you have a similar taste preference to this, then you might not enjoy the burson products in general. I just don't see that many negative reviews for their stuff, and thats why I originally bought the sl, and was very disappointed as I mentioned above, and just wanted to make sure people have all sides available to them before buying.