Finally got my Crackatwoa head amp.....it's been a long time arriving. http://bottlehead.com/product/crack-a-two-a/
Not actual unit
SNA member Mark Houston mwhouston built the kit for me and did a mighty good job of it.
Early days yet, but my initial impressions were that it was basically on a par with my Musical Fidelity XCAN V2, but for a lot more money.
After a few days though, the Bottlehead started to show its excellence with a more detailed and smoother treble. The bass, however, is yet to match the XCAN's, but as with all valve units, burn-in takes sometime, so I'm hoping for improvements there. The soundstage of the Bottlehead is not as wide as the XCAN's, but as in other areas, I'm assured that it will, given time. I'm using Sennheiser HD600 cans and these are also virtually new as well, so some burn-in required there, too.
My source is an Oppo 105D, through Musical Fidelity X10 V3 Valve Buffer with an XPSU outboard power supply.