Gearphoria Volume 7 Number 3

AMP CAMP 18 GEARPHORIA JAN/FEB 2019 Let’s talk tubes, Pts. 1 & 2 You know your 6L6s , but do you know how they work? TUBES ARE ONE of the most talked about aspects of guitar am- plifiers. Everyone seems to have opinions about them, but very few people seem to know how they work. As a builder, I find it funny to have someone call to ask about getting an amplifier with EL34 tone, or 6V6 tone. So many people associate a tube type with an actual amplifier. When people ask about EL34 tone, they are more commonly asking about the sound of a midrange-rich, British- influenced amplifier. When asking about a 6V6, they are usually talking about an American made, tweed-style amplifier. Truth being told, either tube could be made to sound British or American. There are over 25,000 types of tubes out there. Ponder that for a minute. Most of them aren’t made any more, but many are still avail- able. Before I got into making amplifiers, I realized that most am- plifiers used one of only a few pre- amp tubes, a handful of rectifiers, and less than a dozen power amp tubes. As a builder, I realized that most customers are very comfort- able with familiarity. Occasionally, builders will use something oddball because it provides some form of either electrical or sonic value, or just so they can try something new. Tubes, or valves, are actually very simple devices, but rarely explained without a lesson or two in physics. A tube has only a few parts. The tubes we use in guitar amplifiers all follow one of a few designs. Each one closely related to the next. They all have basic similarities. Each one has to have a filament, a cathode, an anode, and a grid. When counting the number of elements in a tube, we ignore REPRINTED FROM GEARPHORIA #2 and #3 (Winter 2012 and Spring 2013)