Finally received this amp two days ago. It took a month and a half but it is here. What can I say, for $300 shipped on ebay to Australia, I have no complaints. The volume knob worked its way loose - but a quick nip with the right allen key solved that.
When I first got it there was a major channel imbalance with everything coming from the right side. I tried swapping tubes left to right and there was no change. Before I threw it in the bin I thought I'd try "burning" it in. Not a huge believer in burn in - but alas that is what was needed. It is now balanced at the center. Burn in it did, as now it sounds so much more refined than before after several days of burning in on and off.
It was not a sound I have ever heard or expected. The only other valve amp I have is the Cayin HA-01. So this is what a "tubey" sound is, as the Cayin is reputed to have a SS tube sound. Like a midrange bubble where the midrange is the most dominant attribute over treble or bass extension. Where the Cayin reproduced the "fuzz" of a distorted electric guitar perfectly, this amp reproduces the "twang" of an undistorted electric guitar perfectly.
I have once declared the K701 unsuited to valve amps - in hindsight, a fool I am, for with one tube amp was my experience. Any blandness targeted at the K701 will be alleviated with this amplifier. Richness of tone density is abundant. The 62 ohm impedance of the K701 should really be considered 600 ohm for all practical purposes - whereas the Cayin will hum with my 300 ohm HD650 the 62 ohm K701 suffers no such ill fate.
And what of the HD650? Some said the HD650 is no match with the Cayin - for which I could not agree, for the pleasures this match gave me were real. With each step deeper into this horrible abyss I emerge wiser and now agree that indeed they are a poor match.
No seriously its great - have yet to roll tubes. I'd pay a LOT more to have this sound now that I have heard it.