Dumble - Marshall 1971 Super Bass

 
This 1971 Marshall Super Bass is the definition of a "wolf in sheep's clothing". 
 
This 100w paint peeling powerhouse was modified by Alexander "Howard" Dumble in 1999. The original back panel of the amplifier was removed, and a three-position switch was added to control ohmage. Mr. Dumble hand-engraved the control settings on the chassis. He also added power supply grounding, replaced by-pass capacitors, upgraded bias filter capacitors, and upgraded power tube cathode bias test resistors. Finally he added an output impedance switch, input resistors and plugged two holes. 
 
These modifications added a lot of gain to the first channel and stabilized the amplifier as a whole making it a more capable and resilient amplifier for use on tour. Which was really the whole point when Mr. Dumble modded an amp! 
The power tubes selected all display hand written notes, dates and are all initialed HAD! Pretty special indeed...