It's been a long time! But this week, the Grail amplifier prototype (AKA the Fletchinator) finally made its long voyage across the Atlantic from Richmond, Virginia to Uster, Switzerland! My good friend Chris Fletcher and I just spent an hour or so on Skype putting it through its paces, and I'm pleased to report that it arrived in one piece, is fully functional, and sounding great. A big thank you to Douglas Nickels for taking it with him on his flight! I evidently also got the wiring conversion from 120VAC / 60 Hz to 230V / 50 Hz worked out properly, which is frankly a bit of a relief, since after rewiring it for the trip I had no way to fully test it here in Richmond.
In any case, there were a number of tweaks to the circuit -- some of them important for proper operation, and others that greatly improved tone, that were made since the last schematic was published here. I will work on producing an updated schematic that reflects the final as-shipped amp, and will post here in due time. Unfortunately, I had a hard-drive crash a couple of months ago from which I still haven't recovered most of my data. I may need to redraw the schematic - but it'll get done eventually. In the meantime, please regard the last posted schematics here as what they are -- draughts.
Finally, Chris has promised to record some stuff with the amp -- I'll be sure to post the results here!
The Fletchinator delivered, and safe and sound in its new home.