one half of a tube in schematic????

[tryonziess]

What is meant when a tube amplifier schematic has one half of a tube in the layout. I know there are many dual element tubes but I am missing something here. Is this like a dual jfet?

Tad

 

[Miles Prower]

Very much like a dual JFET. There are lots of types that include two triodes in one bottle (6SN7, 6SL7, the entire 12A*7 family). You also have types that share common elements (6J6, 6SC7 -- share common cathodes for LTP use).

You also have mixed types (pentode and triode in same bottle: 6KE8 (independent elements) 6X8 (shared cathodes)) mixed small signal triode + large signal triode, and so on and so forth.

Compactron types can have even more units in the same bottle.

 

[mashaffer]

Usually the other half is used somewhere else in the circuit (sometimes other channel).