Pros: Compact, remarkably clear sound, easy to listen for ages
Cons: several weeks of burn-in (but worth waiting for)
I had built and enjoyed the Novo amplifier kit from GSP. I wanted to upgrade to get one of the best headphone amps available.
The Solo Ultralinear is remarkably musical, it opens up the sounds within a mix and brings details out without being harsh. It does a fine job on guitars, acoustic and amplified. The detail and stereo soundstage make individual vocal tracks clear, I could hear vocal backing parts that were previously lost in the mix.
The individual drums and percussion were clearer than before on tracks I knew well, but the punch and resonance of toms surprised me. Basslines have body and clarity, with the track being clearly audible in the mix.
I was impressed with the intial sound which was pretty clear, if a slightly bright new electronics sound. It quickly mellowed with some detail and sounded full with good bass. Over the next couple of weeks the low level details emerged and the positioning of parts in the stereo mix became better and better. The burn-in is 3 or 4 weeks of being left powered up, some users say 500 hours. It is well worth waiting for the end results.
There is a light soft hiss but it is unobtrusive at normal listening levels.
The two inputs and switching arrangement is ideal for my use for phono and CD/DAC inputs.