Re: EL84 variety and screen grid glow

"Alex"

> My understanding is that EL84 is a pentode, not a beam tetrode, so the
> screen grig does not have to be aligned. It runs at a gifferent pitch
and
> with opposite incination (winding direction) with respect to the control
> grid.


** Correct  -  as can easily be verified with a magnifier and with the
valve 
illuminated from behind with a lamp.


> So what is this glow phenomenon?


** First you need to * prove * it exists - OK  ?

Your idea about the temp of the 12AT7 was silly and wrong.

What Sovtek  EL84 is it?

The EL84M or the EH version  ??



> I am not sure the supplier (WES Components) will accept it back,
possibly 
> at
> best it might be replaced. Who knows, maybe they bought of factory
rejects
> from Russia and selling them in Australia for A$13. I would think that
if 
> a
> bias point is 20...25% away from the typical value, the tube shall be
> considered faulty.


** Not at all.

Virtually ALL modern EL84s have the same ( ie high bias) characteristic.

Not since the late 70s have they conformed with the original Mullard
specs.

The closure of all Australian and UK factories and supply from places like

the Czech Republic, East Germany, Russia and China is the correlation.



.....   Phil