EL34 vs 6CA7: two power tubes that can cause a lot of confusion when purchasing replacements, because they’re very similar and are, in fact, replacements for one another. They do, however have different internal designs, and they’ve changed slightly over the years.
In this article, we are going to take a look at two power tubes that are similar enough to be interchangeable, but which have different internal designs: EL34 vs KT77.
Have you been scratching your head about EL84, EL34, and 6L6 Power Amp Tubes? Well, our most frequently asked questions about them are answered here.
Power tube FAQ: What are power tubes?
The first power tube FAQ, of course, is about what they are. Also known as an output tube, a power tube is an electrical component, very similar to a transistor, that is built inside of a vacuum-sealed glass tube. Inside the glass tube are a filament, an anode, and a cathode.
Power tubes can have a dramatic effect on your amplifier’s sound. At low volumes, the difference between one tube and another can be difficult to distinguish; for many listeners, it’s almost not worth talking about. Once you start to push a little air, however, your amplifier will show off what it can do and the power tube will display its individual characteristics more.