I bought one of these recently, an original Mk1 type. It sounds lovely with my HD650s, rich, warm, liquid, analogue, lush, whatever words people like to describe this sort of sound.
The highs may be a bit rolled off which suits me for headphone listening as I find treble grating when it's next to my ears. The key thing is it sounds very natural with no hint of grain that I got from the Graham Slee Solo (Ultra Linear Diamond with PSU1 and, to a lesser extent, the original).
Some reviews say it's less successful with low impedance headphones (which I've not investigated yet), but if you have higher impedance headphones and are looking for a non fatiguing sound this may be ideal, and it's a bargain.
The highs may be a bit rolled off which suits me for headphone listening as I find treble grating when it's next to my ears. The key thing is it sounds very natural with no hint of grain that I got from the Graham Slee Solo (Ultra Linear Diamond with PSU1 and, to a lesser extent, the original).
Some reviews say it's less successful with low impedance headphones (which I've not investigated yet), but if you have higher impedance headphones and are looking for a non fatiguing sound this may be ideal, and it's a bargain.