.....
>Rich asks why Eimac, Svetlana etc don't suggest regulated supplies.
>
>My guess, ..... ........... ............... ......... ...............
............... is that
>as regulated supplies cost money, you make sure that the data sheets
>offer the CHEAPEST possible application - thus no regulation!
The additional parts cost of regulating an 8171 grid bias V supply is
roughly $18 with Mr. Rauch's bias V regulator circuit---which, for Class
AB2, makes $ense.
So why do 100% of the power grid tube manufacturers recommend regulated
screen supplies? It IS possible to achieve okay IMD without a regulated
screen supply. The Henry 4k-2 did it.
Some questions:
-1- If the electric-mains potential decreased 5% in a Class AB1 tetrode
amplifier (with an unregulated anode supply), would the ZSAC (zero sig.
anode current):
A. Decrease?
B. Increase?
C. Remain the same?
-2- If the grid bias V decreased 5% in a Class AB1 tetrode amplifier
would the ZSAC (zero sig. anode current),
A. Increase?
B. Decrease?
C. Remain the same?
IMO, the answers are -1-: A and -2-: A. In other words, the decrease in
ZSAC due to less anode V would be somewhat cancelled by the concurrent
decrease in grid potential. However, if the grid bias supply were
regulated, would this cancellation take place?
>So do any of you have ideas for a session at Dayton 98 on Amplifiers?
I took a Physics of Electricity Class with 250 students. It was
somewhat unwieldy. Later, when I was teaching, I found that a group of
about12 is semi-ideal. However, I learned that one person with an agenda
is poison no matter what the class size. . For instance, it would be
difficult to deal with one person in the audience that profoundly
disagrees with accepted circuit-analysis methodology.
>If
>some of you can volunteer to do say 20 to 30 minute sessions,
IMO, 20 to 30 minute speeches are dead fishes. The malpractice reminds
me of the old lock-to-talk, put the hammer down, AM diatribe days---i.e.,
B-O-R-I-N-G.. Dialogue is what works. // Listening to Congress'
speeches is a sure cure for insomnia. Listening to the House of Commons'
banter is a wake up call.
Rich---
R. L. Measures, 805-386-3734, AG6K
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