[R-390] 12BA6

[Flowertime01 at wmconnect.com]

Scott,

The 12BA6 is not a JAN tube.
It is just a commercial tube. 6BA6 stuff with a 12 volt heater running at 
1/2 the 6 volt current. The couple Europe numbers are the only matches.

Lots of pentodes that come close in pin configuration and performance.
Most vary at close to cutoff and total power. 

In an AGC controlled circuit this is a problem. If you are not operating 
variable gain or at cut off, lots of other tubes will work in the circuit very 
well. Tube manuals must cover every Bevis and Butthead use. So lots of 
possibilities will never make the cut.

Start with tubes in the same base diagram. Then look at close relatives 
that may work as the actual tube socket is wired to see what will plug in.

12BA6's are still available so no reason not to just go hunting to find 
what you need.

Roger AI4NI