Hi,
I'm building a pp1-c as designed by Allen Wright. As I am a bit cash strapped at the moment I want to do this as cheaply as possible. Given that i don't have any 470R power resistors at the moment, what would the effect of going to 1.2K be?
I mean they are only there for stability and current control reasons, or am i wrong there?
thnks
Joris
I'm building a pp1-c as designed by Allen Wright. As I am a bit cash strapped at the moment I want to do this as cheaply as possible. Given that i don't have any 470R power resistors at the moment, what would the effect of going to 1.2K be?
I mean they are only there for stability and current control reasons, or am i wrong there?
thnks
Joris
The only 470 ohm resitors on the PP-1C diagram are the EL34 cathode resistors, specified as 470 ohm 10 watt.
Diagrams here: http://www.vacuumstate.com/index.dna?rubrik=8&lang=2&a=%CC%DF43%9F%FB%C4k&b=735289.6650079573
The resistor value should not be too much different from the 470 ohm.
You might get away with two 1200 in parallel for 600. Three for 400 ohm may run the tubes a bit hot.
5 watt rating might be OK instead of the 10 watt specified.
--
SveinB
Diagrams here: http://www.vacuumstate.com/index.dna?rubrik=8&lang=2&a=%CC%DF43%9F%FB%C4k&b=735289.6650079573
The resistor value should not be too much different from the 470 ohm.
You might get away with two 1200 in parallel for 600. Three for 400 ohm may run the tubes a bit hot.
5 watt rating might be OK instead of the 10 watt specified.
--
SveinB
Last edited:
The PPC-1C schematic
Schematics
Clearly show screen grid resistors of 470 Ohms (triode strap resistors). Value is not super critical, 150 Ohms is minimum recommended for triode straps. 2 of your 1K2 in parallel to give 600 Ohms which also would be fine.
Cheers,
Ian
Schematics
Clearly show screen grid resistors of 470 Ohms (triode strap resistors). Value is not super critical, 150 Ohms is minimum recommended for triode straps. 2 of your 1K2 in parallel to give 600 Ohms which also would be fine.
Cheers,
Ian
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