After one week of burning in about 3 hours a day the sound has softened and warmed.
I think this a remarkable amp for the price, matching the quality of the Terminator DAC.
I definitely prefer it to the V281 for its greater clarity, smoothness and its resolution (I hear details not heard before). The dynamic range is big: keep the quiet bits quiet or you are in for a shock when a loud bit comes along. There is no hint of roll off in the treble, the mids are lovely and the bass is full (maybe a little too much) and extended. The overall sound presentation is sweet and smooth as silk.
The only adverse criticism I have is that the presentation is rather close up and so the sound stage is very wide but lacks corresponding depth.