Well it's been a couple weeks, feels like much longer, this is a lifetime in DIY years...a lot has happened so thought I would post a little update, keep it short and sweet without all the technical mumbo jumbo.
Here is the radio I am restoring, it is 95% done, just needs an IF / RF alignment, which might necessitate getting an RF signal generator that can do signal modulation...TBD on that front. This radio is from 1948, polished up the bakelite nice and shiny.
I think I mentioned I was building a tube amplifier protoboard, it is done, here is a single channel of my 801A A2 amplifier built out on it. I'll finish the other channel today.
This is a pretty complex amplifier, at least by my standards, very much a 'DIY Only' affair. The screens of the EF37A pentode inputs are regulated by a VR105 glow tube, which makes for a very nice effect. That is ionized argon gas, aka plasma.
You might have noticed from the other pics, I have significantly upgraded my DIY work area digs. I built a workbench in my basement. My DIY life is so, so, SO much better, and more efficient.
Last thing - I am going to build a solid-state power amplifier, but not just any, will use SITs, aka VFETs. These transistors, re-popularized by Nelson Pass' First Watt line, have triode-like characteristics, can be operated in single-ended class A without use of negative feedback, or output transformers given their very low drain resistance. They are on the verge of extinction, so figured I'd grab some while they are still available. I have a design drafted, but realistically this is quite far away.
Here are the curves of this particular one, THF-51S.
Okay, that's all I've got! I have been lurking here and there, hope everyone is enjoying their tube / amp rolls