My interest and fascination with inexpensive "radio" valves using series- connected line- operated heaters didn't stop with the completion of "Li'l 4x4". At the same time, my lovely wife was a bit envious of that little rock-speckled box that sits in our room. So what better project than to build her very own tube guitar amplifier?
"SPUNKY" Shaza Jane
by Fred Nachbaur, Dogstar Music
|The resulting project sports up to about 8 watts of output power, which when connected to an efficient speaker is plenty of power for small rooms. For larger rooms, the unit is easily mic'd into the house PA system.|
9JW8 (pentode/triode) - input stage (pentode) and second amp (triode)You've probably never heard of the 9JW8, or even of its 6-volt equivalent the 6JW8. Don't feel bad, I wasn't familiar with it either. For this project I wanted to use a pentode/triode pair, since I like pentodes as input amplifiers and wanted an extra triode section for an added gain stage. I considered the 7199, but it would not have worked well in my line-operated heater scheme. Besides, I tend to shy away from tube types whose price is inflated by "manufactured demand". (So don't expect to see a 300B design from me any time soon!)
12AU7 (dual triode) - third amp, phase splitter
4 x 35C5 (beam pentode) - PPP output stage