For the technically inclined, here are two great resources for understanding what exactly is going on under the hood of your favorite amplifier:
Teemu Kyttälä, better known as teemuk on several forums, posted this excellent book titled
Solid-State Guitar
Amplifiers over at the
solid state amp forum. I highly recommended it (even though much went over my head) as it includes breif overviews of many of the tube emulation styl circuits current on the market such as Peavey's TransTube and Vox's Valve Reactor.
At the other end of the spectrum, Charles R. Couch (also known as randyc on several forums) has posted a rather excellent tube amp book titled
Designing Vacuum Tube Amplifiers and Related Topics. Do to the potential danger of tinkering with tube amps, please observe the following disclaimer:
Quote:DISCLAIMER: I [Charles R. Couch] assume no responsibility for the accuracy or completeness of this material or the use to which it may be put. The material discusses designs of electronic equipment in which hazardous high voltages are used. It is your responsibility to make yourself familiar with these hazards should you attempt to duplicate any of the information contained in this material.
The Trainwreck Pages by Ken Fischer - Very cool technical paper including history of tube amps and some general mods with schematics.
Novice guide to the basics of tube gain stages:
http://www.diystompboxes...m/pedals/tubedummy.html
Horrible layout, but nice list of low wattage tube amps:
http://www.jedistar.com/low_watt_amps.htm