Makers
Dr Z
Gomez
Allen
Naylor
Vox
Electrosonic

Schematics
Fenderholic
Tonstacks
Tremolo

Parts & Kits
kcanostubes.com
thetubestore.com
dougstubes.com
tubesandmore.com
audiotubes.com
military-tubes.com
mojotone.com
ees-audio.de
tubedepot.com
hoffmanamps.com

Know-How & History
vibroworld.com/magnatone
guitaramplifierblueprinting.com
myrareguitars.com/vintage_magnatone
preamp-tube-gain-factors-and-substitution-chart
tonequest.com
geofex.com
ampwares.com