Project 1 (July 2009): SOLD! Marshall 1959 guitar amplifier with low-voltage option and external bias adjust
Marshall 1959 100-watt "Plexi" circuit, constructed with mostly modern components and a few New Old Stock parts, all available online.
Project 2 (March 2016): Marshall 1959 guitar amplifier, 12-series specifications
From legendarytones.com: "For those in the know, the original Marshall 12000-series amps (called that
because they had serial numbers that were in the 12-thousands) made from late 1967 through 1968 have specific
circuit and component configurations that are unique compared to those that came before or after them...they
were a unique series that captures a particular sound that could grind with gain (in the case of the Super Lead),
but also do so without being sharp on the upper frequencies. Later plexi models were voiced more aggressively
but with added treble to achieve the effect, in addition to other changes in filtering, affecting the feel."
The empty chassis, made of pressed steel.
Tube sockets and panels.
Twisted wiring for AC heater supply.
Power and output transformers, hand wound to exact material and geometry specifications.
Initial wiring of transformers.
Switches, potentiometers, and other hardware installed.
Turret boards ready for population.
Power section and fuse holders installed.
Turret board components soldered in place. Getting close...
Circuit board detail.
Powered on! Testing at 440 Hz with oscilloscope.
Chassis installed in custom-built cabinet.
...Rock on!
Signal chain: Hand-built replica Frankenstrat guitar -> Hand-built MXR Phase 90 -> MXR 10-band EQ -> Project 2 Amplifier (100W into fan-cooled dummy load) -> Line out transformer -> Maestro Echoplex EP-3 -> Project 1 Amplifier (100W into 4x12 speaker cabinet)
