What difference does the glass tube shape make?
Not much really. A 6L6G might not fit in equipment designed for a 6L6GB. Theoretically, a 6L6G would dissipate heat a bit better due to its larger glass area. -Jim Cross • Is there a way to design for increased 2nd harmonic distortion without getting much 3rd (which gives a congested sound)? Push-pull amps have the inherent characteristic of even order harmonic distortion cancellation. The more carefully the amp is AC balanced, the lower the even order products. This means a couple options exist: • Deliberately unbalance the output section, either by an imbalance in the phase splitter, or by using output tubes that are mismatched (primarily in terms of transconductance, not plate or cathode current). • Don’t build a push-pull amp, use a single ended amp. I’ve watched on my spectrum analyzer as I adjusted the AC balance on an amp. What occurs is that if you “unbalance” the drive to the output tubes in the “right” direction (you need to be able to see on the analyzer to know which way is
