Amplifier Features Amp Type Tube Chassis Material Aluminum Rectifier Type Tube or Silicon Diodes with Patented Rectifier Tracking™ (Auto-matches Tube for all 10 Watt Modes, Diode for all 90 Watt Modes, selectable Tube or Diode for 45 Watt Modes on Channels 1 and 2, Diode for 45 Watt Mode on Channel 3 - Patent 7,193,458) Rectifier Tubes 1x Mesa 5U4GB Variac Power Switch Tweed Power Switch Preamp Tubes 7x Mesa 12AX7 Power Amp Tubes 4x Mesa 6L6 STR 440 Bias Switch for Alternate Power Tubes Types Bias Select for 6L6 or EL-34 Maintenance Free Fixed Bias Yes Wattage(s) Quick Reference 10, 45 or 90 Watts - Channel Assignable - See Amp Details above for more information Built-In Power Amp Attenuation n/a Power Amp Details (Class & Wattage) Mesa's exclusive Simul-Class™ Power Amp featuring Multi-Watt™ (Patent 7,602,927) and Duo-Class™ (Patent 7,173,488) technologies which provide three power and three operating-class options that are channel assignable via 10/45/90 Watt Power Switches: Choose 2 power tubes operating in pure vintage Class A (single-ended), producing 10 Watts - 2 tubes running in time-honored Class A/B producing 45 Watts or 4 tubes running in Mesa's legendary Simul-Class™ Power that blends the best of Class A and Class A/B simultaneously to produce 90 Watts of pure tonal magic Convection or Fan Cooling Fan Cooled with On/Off Switch Number of Footswitchable Channels (or Modes) Three Channels Number of Style Modes Nine Number of Style Modes Per Channel Three Types of Style Modes Per Channel Ch. 1 = Clean, Fat or Tweed
Ch. 2 = Edge, Crunch or Mark I™
Ch. 3 = Mark IIC+™, Mark IV™ or Extreme Channel Controls Each Channel features Independent 3-Position Style Mode Switch, EQ Assignment Switch (On, Off or Footswitchable), 90/45/10 Watt Multi-Watt™ Switch Gain, Treble, Mid, Bass, Presence, Master, Footswitchable or Auto- Assignable Contour Depth Control, Footswitchable All-Tube, Long Spring Reverb Control, Patented Rectifier Tracking™ (Auto-selects Tube for all 10 Watt Modes, Diode for all 90 Watt Modes, selectable Tube or Diode for 45 Watt Modes on Channels 1 and 2, Diode for 45 Watt Mode on Channel 3 - Patent 7,193,458) Graphic EQ and/or Contour 5-Band Graphic EQ and Contour Reverb / Effects & Bypass Options All-Tube, Long Spring Reverb with Independent Channel Controls - See True-Bypass Options below for more information Effects Loop & Bypass Options Fully Buffered FX Loop w/Send Level Control - Footswitchable, Channel Assignable or True Bypassable - See True-Bypass Options below for more information Global Output Level Control Yes (Over all channels when activated) Global Solo Level Control & Bypassable Options Yes (Over all channels when activated)- See True-Bypass Options below for more information True-Bypass Options True-Bypass Switch removes FX Loop, Output & Solo Level Controls Tuner Output Yes (back panel) with Footswitchable Mute External Switching Jack Options and/or Midi External Switching Jacks for Channels 2, 3 (Ch. 1 is default), EQ & Solo Speaker Outputs Two 8 Ohm and Two 4 Ohm Cabinet Simulation - Direct Live/Recording Output   Headphone Output n/a Slave Output Yes with Level Control