What is the difference between Preamp Tubes?
The main difference you have really is from a gain point of view. The preamp tube’s important in the signal path because it is the first point at which the signal from your guitar is amplified. So, you have a good opportunity there to import kind of a gain characteristic on the signal by using a particular type of preamp tube, be it an ECC83 or 12AX7, variations of those, each of which will have slightly different gain characteristics.
If you want an amplifier which has a particularly clean sort of sound, then really your first point of amplification should be a relatively low gain preamp tube. Obviously, if you want something that has a little bit more gain in there, then the first point you have something which has more gain content and if we can drive the existing tubes harder.
What is the difference between EL34 and 6L6 tubes?
Parent tubes, it’s more fundamental about what sort of flavor of tone you want. If you think about the classic EL343 guitar tone, an EL34 guitar tone is a particularly British guitar tone. It has a slight mid-range scoop, which to European ears is quite a pleasing sound. The other main type of output tube is a 6L6. 6L6’s are much less scooped from an EQ point of view. They have a much more flat frequency response.
Now, if you think about the type of amplifiers that use 6L6s, if EL34s are a particularly British European sound, then 6L6s are very much an American kind of sound, almost to the extent that it used to be possible to put 20 guitar players in a room, play an EL34 loaded amp, play a 6L6 loaded amp and then get people to stand next to the amps that they liked and you could tell their nationality.☺
6l6 vs el34
So, EL34s are a bit more scooped, 6L6s have this bit more of a mid-range presence. So, if you think about the archetypal country style performers that are very bramete and clean and have lots of headroom, versus the amplifier which runs a bit more darker in the mid-range, a bit more distorted, has a bit more of a rock guitar tone, then as with all things, there are exceptions to every rule. But really if you think about EL34s as being a bit of a mid-range scoop, 6L6s as not having that mid-range scoop, but quite a nice mid-range presence, and then you have variations of those. You have EL84s, which are in essence a small bottled EL34, so it has the same kind of mid-range scoop or recessed mid-range that gives you that pleasing source of sound.
And then you have iterations of 6L6s, like 6V6GTs 4, which are, I should say that the EL84 and 6V6GT are basically lower output power tubes with the same sonic characteristics as EL34s in an 84s example or 6V6GTs, and of course the 6L6s. They just give amp builders just different options at producing power amps in smaller packages, while still maintaining the same kind of broad, sonic characteristics, an EL34 or 6L6.
And then obviously you have variations within the EL34s in different grades, different bottles, that sort of thing and the same with 6L6s. So, if you look at those in more detail, got lots of variations between the different types within the 6L6 family.
But ultimately it’s, from a guitar player’s point of view, you think EL34, reduced mid-range, 6L6 mid-range content is still there. And that’s it.