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In Reply to: RE: now I am really puzzled ...... posted by vinnie2 on April 27, 2016 at 13:00:55
This schematic is inoperable!
1.)
If the second #26 grid voltage is 110V and cathode voltage is about 5V on 820R (target anode current is 6mA), the grid-catode voltage is +105V!!
The second #26 tube will destroy (grid-cathode diode will conduct several mA current).
2.)
The #45 cathode voltage is 1200R*0.034A=40.8V
If anode voltage is 223V and cathode about 41V, anode-cathode voltage is 182V.
Datasheet: 182V, 34mA -> grid-cathode voltage about -33V.
So grid will be at -8V potential.
IMHO the original schematic was AC coupled, capacitors between stages.
Grid to ground resistor shows this.
Impossible to build from well fuctioning AC coupled amplifier DC coupled ones without complete redesign.
Follow Ups:
There are coupling caps between the stages that aren't drawn in the schematic.
I'm puzzled about how the components on the 45 cathode work. Shouldn't they be the same layout as the 26?
Good catch. Boy did I ever screw up that schem. It is the same setup as the 26's, just different values. see my last post at the top of the thread for what comes next.
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