1970-1975

Configuration: Head
Power: 435 Watts
Effects: Reverb, Tremolo

SCHEMATIC

• 400PS

LAYOUT

• Front Panel: Power Switch, Standby Switch, Pilot Light - "Bass" In, In, Deep Switch, Volume, Treble, Bass - "Normal" In, In, Bright Switch, Volume, Treble, Middle, Bass, Reverb, Speed, Intensity - Master Volume
• Back Panel: Speaker Jack, Speaker Jack, Speaker Jack, Output Tubes Matching, Vibrato Jack, Reverb Jack, Hum Balance Preamp, Fuse, Ground Switch

CABINET 

• Dimensions: 11½'' x 28'' x 12¾''
• Tolex: Black
• Grill Cloth: Blue / White / Silver or Black w/ White Trim
• Logo: Grill Mounted, Raised, Chrome and Black Script w/ Tail
• Handle: 3x Black Strap
• Feet: Casters
• Corners: Chrome Corners w/ Lip
• Knobs: Black Skirted w/ Chrome Center Numbered 1-10

SPEAKER 

• Size: Fender Bass Bottom Ext Cab 1 x 18 with folded-horn design
• Impedance: 4 ohms
• Model: ?

 TUBES

• Pre amp: 2 x 7075 ; 12AX7, 6L6GC
• Power: 6 x 6550
• Bias: Fixed
• Rectifier: Solid State

Comments: The 400PS was the first large amp made by CBS, and the largest ever made by Fender. The chassis alone weighs as much as a Twin Reverb.
The output of the 400PS was divided into three 145 Watt power sections so it took three cabs to get the entire 435 Watts.