"RapidRonnie"


What a pile of nonsense!

I'm afraid it's true. Discrete power transistors vary much more than
tubes of a given type and manufacture run.


** Complete bull****.

Power BJTs from the same run are very nearly all identical.

They can be used in parallel just fine.


That's why construction or
repair of high power solid state amps requires either factory-matched
sets or the use of a curve tracer to sort through piles of them.


** You have NO idea what you are talking about.

A curve tracer is just about useless for power BJT matching where parallel
operation is needed.

You need a wide range Vbe / Ic match and that ideally means devices of the
same type, maker and batch.

With power tubes operated in parallel - mating up old and new or differing
brands leads to tears just the same as with BJTs.


Now, MOSFETS are another matter.

The laterals ( aka audio fets) match in parallel very nicely.

The verticals ( aka switching fets) are pigs.




......... Phil