Although the musician in me appreciates that a huge amount of what we consider to be great guitar tone comes from the head and the fingers, the hard-core engineer in me understands that there are factors in the inner workings of guitar gear that improve the chances of realising that elusive tone. But what are those factors? Well, as the reader is probably aware, I’m strongly of the opinion that tubes, the component in a guitar amplifer that does the work of shifting electrons around is a factor, if not the key factor. After all, there must be something in why these archaic, hot, high-voltage devices persist despite the advent of more convenient, less costly technologies. And not a decade passes without some new technological development emerging, such as op amp, JFET, digital modeling, profiling, tube-on-a-chip, FET-in-a tube, etc all claiming to deliver the magical sound of tubes. Yes, there’s definitely something about tubes that works wonders for electric guitar tone, and this is why I remain fascinated by what makes a good tube and Mullard, who were renowned for making exceptional tubes.