I've dusted off LTSpice, and I'm getting started with some circuit simulations!

While I've learned a lot, what's probably the most important thing is this: when they say tube amps are dangerous, they are not kidding. The power stage of this ity-bity 5 watt Spuntone operates at 275V loaded, and theoretically can produce 550V unloaded (although from what I've read, people are measuring more like 400V in reality). I'm not sure yet how much the voltages scale upwards with the wattage of the amp, but I imagine a 200W all-tube quad KT88 configuration will contain voltages well beyond lethal potentials.

I haven't had a chance to look further into high voltage digital pots or voltage controlled resistors yet. In the interest of getting this project out of the computer and onto the workbench, I'll be making the first iteration of the Spuntone with regular old manual pots first. Then I'll look into retrofitting with the fancy stuff, as we'll still need to test everything that goes into the final build on the smaller scale.

Expect a functioning build of one kind or another by the end of the year, and a finished Spuntone sometime in 2015 (hopefully in the spring).

P.S. - thanks for the skulls! I'm still getting skulls every now and then despite the slow progress and lack of test data, which is super cool. Let me know what you're interested in and what you'd like to know about the project. And please point out any mistakes or errors in assumption that I'm making; after seeing those voltage numbers, I'd rather be shamed on the internet than burned in the workroom.

Also, a buddy of mine from college, currently living in Seattle, is getting to work on his own custom tube amp. I've been talking to him about these projects, and we might be borrowing each others ideas, so this may turn into a bass and guitar amp project! You know, besides the dinky guitar one I'm already making.