200, 200, -4.6, 50 according to page 4 of
http://www.retrovox.com.au/STC6BQ5.pdf
Page 7 of the same report shows curves for Vs = 200, so you can
check.
There are tonnes of sites with EL84 data, check via
http://www.duncanamps.com/
In general, you need to find the anode characteristic curves for
whatever screen voltage you are using. Choose the Va you will use,
and draw a vertical line on the curves at that voltage. It will
intersect with several curves. Find one intersection that gives a
convenient current: that gives you the required grid voltage. You
may need to interpolate between two intersections.
There are other presentations of the same data: grid and screen
characteristics, that can also be used...you just need one that
shows the relationship between Va, Vs, Vg and Ia. That's 4 variables
though so no single graph can express it all. That's why each set of
characteristics is a family of graphs, each with a family of curves.
Perhaps screen characteristics for Va=200V would be better for you.
Dunno if they are in that report, I don't have broadband.
cheers, Ian
"Richard J" wrote in message
...
Hi guys -
have got myself a tube tester that can do all sorts of tricks,
itīs a German
RPG70. It needs recalibration on the 50mA scale of the instrument.
Long
story, but getting there fast. Have documentation, but no
calibration
instructions.
Short question:
How much anode current will/does a new EL84 draw at the following
parameters
(stipulated by the RPG70 test card for EL84)?
Ua=200V, Ug2=60V, Ug=0V
An estimated guess would be somewhere in the region 17-20mA, but
knowing is
a lot better than guessing.
From the tube data sheet, I can guess that it would draw abt 48mA
at Ua=250,
UG2=250, Ug=0V. But: the tube data sheets all begin at 250V....and
not
200V - and my tube tester hasnīt got a 250V option. My math
doesnīt cover
this....
I have the following tester options:
Ua=25, 50,100,150,200V
Ug2=20,60,100,150,200V
Ug= negative 0-18V
Help, pse?
/Richard (used to simple emission testers, this is a different
ballgame)