If you want a small, cool tube amp for next to nothing, check out the Epiphone Valve Junior Combo. It's a 5 watt, single-ended Class A amp. It sounds really good and has a low price tag. Don't let that fool you - it's a great, small, but powerful tube amp. The Epi Valve JR is simple to operate - just a volume knob - that's it! Even so, it can go from a nice clean tone to a great overdriven blues tone, depending on how much you turn that one volume knob.
Andy Z has posted some nice clips of the Valve Junior Head - go and
listen to the Epi Valve Junior clips on the Institute Of Noise website.
Epiphone has now released a head version of the super-cool Epi Valve Junior amp. They made some improvements on it too. The head version has DC filaments for both the preamp and power sections, reducing unwanted filament hum. It also has 4, 8, and 16 ohm speaker outputs so you can drive any kind of extension speaker, from a single 8" speaker to a 4 x 12" cab. This is an awesome little amp, that gives you great tube tone to a bargain price!