Here’s a couple of pages scanned from the tome (RDH4) on an interesting cross-coupled phase splitter/semi-parametric tone control. Page 1 and Page 2. It works rather well, and could be found (albeit slightly adulterated) in my preamp… although not any more.
Here is a simple, 10W triode-wired PP EL34 interstage coupled hifi amp. I use this amp for my computer sound system, and it sounds fabulous.
I made up a high current 12VDC power supply, used to emulate an automobile electrical system. The schematic is here.
Here is a small collection of datasheets I found useful.
A very ambitious project… scanning in the entirety of Karl Spangenberg’s epic Vacuum Tubes. Click HERE for a single, self-extracting archive file of the jpgs (~70Mb). A nice large PDF file can be found here.
Color codes for typical power transformers.
Here’s a handy Wire Table.
Datasheets for Thordarson Input trannies.
Typical output transformer wire color code.
Amperex 1963 Electron Tube Catalog.
Here’s a guide to typing extended ASCII characters from your Windows Keyboard.
Here’s a quick and dirty low Z bias supply.