Hi! New guy here -- thanks for having me! :)
I'm fairly new to the world of electronics, and the most ambitious project I've completed to date has been performing the Lyle Mods to my Marshall Class 5 amp. (Successfully, even!)
But I got the bug bad. :) My copy of Morgan Jones' Valve Amps book isn't even here yet, but I've already gotten started...
I've salvaged an old Capehart-Farnsworth AM/FM Radio & Phonograph to do my first salvage amp creation. So far, there's a lot that's very familiar. But, of course, this didn't start life as a guitar amp so there's some oddball stuff, too.
The good news is I got a power transformer, output transformer, Alnico speaker, and tubes and bases for a rectifier, pre-amp, and output tube.
Plus a lot of caps and resistors which may or may not be very useful -- and a pile of other junk that certainly isn't.
I've studied the schematic and stripped it down to what I think are the bare bones of what a very basic guitar amp would need. Like so:
Now, I'll freely admit I've completely cribbed this off of C-F's original schematic. Aside from a LOT of deletions, and adding an input jack, I haven't changed anything. While I had some wacky ideas about making this into something it isn't, I really don't need to buy a bunch of new parts when this might not work at all, and also -- these parts DID work well enough together at one point. I'm not likely to blow out this fragile speaker* or burn up the OT or whatever, by sticking with this layout.
[* -- The speaker is a nice big 12". But it is LIGHT, with a very small alnico magnet and about a 1" or so voice coil. I don't think I'll be rattling the windows too badly with this one. But it might sound cool for late night practice...]
But the cap and resistor values I see in the tone stack don't look like numbers I'm familiar with. I see 3.2 Meg. Ohms on the tone pot. Wow. And about half that on the volume pot. I know the screened frequencies cut out by these will be a function of both the resistance and capacitance in the circuit, but is this even close to right for a guitar?
And what about moving the tone stack in front of the pre-amp? I didn't, but wouldn't that give me control closer to the final product?
I sure do appreciate any thoughts, comments, warnings, improvements, suggestions, or just well-wishes. :)
Thanks!