All-Tube Guitar Amp Heads use an analog tube valve for the preamp and a tube for the power amp section, producing the warmest and richest tones you can get out of a guitar amp.
Fully tube amps are usually use 12AX7 or similar tubes for the preamp, and larger EL84 tubes or 6L6 tubes for the main power amplification section.
Tube amps cost a bit more than their solid state counterparts, but they are the standard equipment of professional guitarists.
All-Tube Guitar Amp Heads use an analog tube valve for the preamp and a tube for the power amp section, producing the warmest and richest tones you can get out of a guitar amp. 
