What is B, P, and G for tube amplifier output transformer?

We had been asked the questions that what B, P, and G for tube amplifier output transformer is. Maybe it is a simple question for tube amplifier audiophiles, there a brief for it below.

The primary of tube amplifier output transformer generally has two, three and five connection terminals.

The circuits of single tube type class A amplifier Among them include:

1. The primary is 2 connection terminals, P is connected to the screen, B is connected to B+ (that is, DC high voltage power supply)
2. The primary is 3 connection terminals, P is connected to the screen, G is a Ultra-linear tap (connected to the second gate of the power amplified tube such as 6P6P, 6P1, 6P14, etc.), B is connected to B+ (that is, DC high-voltage power supply)

 

Push-pull circuit:

1. The primary is 3 connection terminals, the transformer primary has two P terminals, and one B terminal, two P terminals respectively is connected to the screen of tube No and No2, B then connected to B + (that is, high-voltage DC power supply).Here, tube No.1 and No. 2 are two push-pull arms, same as below.
2. The primary five connection terminals, the five primary connection terminals of output transformer are: P1, G1, B, G2, and P2. Among them, P1 is connected to the screen of tube No. 1, G1 is connected to the ultra-linear tap of tube No. 1, P2 is connected to the screen of tube No. 2, G2 is connected to the ultra-linear tap of tube No. 2, B is connected to B+ (that is, DC high voltage power supply). There is an example below for push-pull circuit.