Tremolo – a cyclical change in amplitude manifesting as a rhythmic pulsing – debuted in a Fender amp, the Tremolux ... it’s tuned to emulate the valve and output transformer saturation ...

The amp was so ubiquitous that Marshall used ... It’s worth noting that for an extra $600/£640 (and an extra 9.54kg!) Fender’s all-valve version is available, but you won’t have access ...