Arfa Daily wrote:


Perhaps someone who purports to know the difference could enlighten me, as I
really am interested in knowing.

Arfa



Well, I don't purport to KNOW if there is a difference, but one thing
comes to mind. Once the makers start to use a cathode, which is
effectivly a rigid cylinder, then the grid to cathode spaceing can be
much reduced. Ending up in the 50's with the very high gm frame grid
valves like the e810f and d3a. The DH valves, because of its "floppy"
fillament needed to keep the first grid out of the way. I wonder if this
is in part the cause of the difference. Its certainly the case that IH
valves seem to show far more of the island effect in their curves. You
only have to compare (for example) a 2a3 and a triode connected 807 to
see the difference, and this effect is a direct result of grid to
emmiter spacing.

--
Nick