Amplifier Features
Amp Type:        Tube
Chassis Material:        Aluminum
Rectifier Type:        Selectable and Channel Assignable Dual Rectification (Tube or Silicon Diodes) with Patented Recto Tracking (Patent 7,193,458). Recto Tracking auto-matches the correct Rectifier compliment for the number of Power Tubes in use.
Rectifier Tubes:        2x Mesa 5U4
Variac Power Switch:        Bold/Spongy Power Switch
Preamp Tubes:        6x Mesa 12AX7
Power Amp Tubes:        4x Mesa 6L6 (or EL-34)
Bias Switch for Alternate Power Tubes Types:        Bias Select for 6L6 or EL-34
Maintenance Free Fixed Bias:        Yes
Wattage(s) Quick Reference:        50 or 100 Watts - Channel Assignable - See Power

Amp Details for more information
Built-In Power Amp Attenuation:        n/a
Power Amp Details (Class & Wattage):        Class A/B Power with Mesa's patented Multi-Watt Channel Assignable Power Amp (Patent 7,602,927) - Provides two power options that are channel assignable via four 50/100 Watt Power Switches: Choose 2 power tubes, producing 50 Watt of small block-power or all 4 power tubes producing 100 Watts of big-block horsepower and authority.
Convection or Fan Cooling:        Convection
Number of Footswitchable Channels (or Modes):        Four Channels
Number of Style Modes:        Twelve
Number of Style Modes Per Channel:        Three
Types of Style Modes Per Channel:       
Ch. 1 = Clean, Fat or Tweed
Ch. 2 = Clean, Fat or Brit
Ch. 3 = Raw, Vintage High Gain or Modern High Gain
Ch. 4 = Raw, Vintage High Gain or Modern High Gain
Channel Controls:        Each Channel features Independent 3-Position Style Mode Switch, 50/100 Multi-Watt Switch, Gain, Treble, Mid, Bass, Presence, Master, Footswitchable Reverb, Assignable Dual Rectification with Recto Tracking (Diode or Tube - Patent 7,193,458), FX Loop Assignment Switch (allows you to auto-assign FX Loop to either come on or off when the channel is activated or be controlled via the footswitch)
Graphic EQ and/or Contour:        n/a
Reverb / Effects & Bypass Options:        Footswitchable, All-Tube, Long Spring Reverb with Independent Channel Controls (back panel)
Effects Loop & Bypass Options:        Fully Buffered FX Loop with one Send Level Control - Footswitchable, Channel Assignable per Channel or True Bypassable - See True-Bypass Options below for more information
Global Output Level Control:        Yes (Over all channels when activated) - See True-Bypass Options below for more information
Global Solo Level Control & Bypassable Options:        Yes (Over each channel 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 1, 2, 3, 4, Reverb, Tuner Mute, FX Loop & Solo
Speaker Outputs:        One 16 Ohm, One 8 Ohm & Two 4 Ohm
Cabinet Simulation - Direct Live/Recording Output       
Slave Output:        Yes with Level Control