The Marshall Super Lead 100 Model 1959, also known as the “Plexi,” is one of the most iconic amplifiers in rock history. Produced from the mid-1960s, it defined the sound of generations of guitarists with its powerful, dynamic, and aggressive tone. Equipped with four EL34 power tubes and a preamp section based on ECC83 valves, the Super Lead 100 left an indelible mark on live and studio music.
Around the same period, in the Netherlands, the London City amplifier head was produced, heavily inspired by the circuit and design of the Super Lead. This model, now highly sought after by enthusiasts, shares much of the same construction philosophy and is fully compatible with many of the components used in original Marshalls.
Compatible Replacement: SB-LAB 25S120
The SB-LAB 25S120 power transformer is designed as a direct replacement for Marshall Super Lead 100 and London City amplifiers, in cases where the original transformer is faulty or beyond repair. It faithfully reproduces the electrical and mechanical characteristics of the vintage component:
- High voltage secondary 350-0-350 V / 250 mA
- Filament secondary 6.3 V / 6 A
- 5 V / 3 A secondary for rectifier use
- 50 V secondary for negative bias
- 230 V primary, compatible with modern mains voltage
- Dimensions and mounting centers identical to the original
Built using traditional techniques and high-quality materials, the SB-LAB 25S120 transformer is ideal for faithful repairs and conservative restorations of Marshall and London City amplifier heads from the ’60s and ’70s.
Availability
The 25S120 model is available on order. Upon request, customized versions can be supplied for different chassis or specifications. For further technical details or to request a quote, visit the SB-LAB contact page.