Mesa/Boogie Express 5:50 Plus 5/25/50-watt Tube Combo Amp Features:Open-back all-tube 1 x 12" combo, custom designed and handcrafted in Petaluma, CaliforniaAll-tube amp with 5 x 12AX7 preamp tubes and 2 x 6L6 power tubes50-watt Class A/B, 25-watt Class A push-pull, and 5-watt single-ended Class A o..