17-11-2015, 02:08 PM
Hi Nick.
My intention was to draw out some circuits of the sets I've made with the Russian valves. I've just had no time and getting into the shed has been a little tricky.
Basically I have been using 1X18b valves for detector and audio preamp. For the filament I have used a "C" cell and a 25 ohm potentiometer to adjust the filament for 1.1-1.2 volts. Oddly with these valves the anode is not the best electrode for operating the valve in triode mode, using the G2 is perfect and you can then strap the anode to it if desired, it makes no difference to performance though.
For output I use 1X29b valves, it has a centre tapped filament and I connect them up for parallel configuration. I connect the valve up as a pentode and the output then is taken from the Anode, the G2 can be fed from a 47k resistor as current drain is tiny on the G2 on these valves, the screen and G3 of the valve is taken to the centre tap of the filaments.
These little valves will work a treat on your little circuit and will give an output at an HT as low as 18 volts.
They are great little valves for experimenting with and I'm about to embark on an FM radio project using Super-regen, not sure if it will work but I don't really see why not.
I'll still try to draw out a couple of circuits but I do it the old way with pen and paper.
My intention was to draw out some circuits of the sets I've made with the Russian valves. I've just had no time and getting into the shed has been a little tricky.
Basically I have been using 1X18b valves for detector and audio preamp. For the filament I have used a "C" cell and a 25 ohm potentiometer to adjust the filament for 1.1-1.2 volts. Oddly with these valves the anode is not the best electrode for operating the valve in triode mode, using the G2 is perfect and you can then strap the anode to it if desired, it makes no difference to performance though.
For output I use 1X29b valves, it has a centre tapped filament and I connect them up for parallel configuration. I connect the valve up as a pentode and the output then is taken from the Anode, the G2 can be fed from a 47k resistor as current drain is tiny on the G2 on these valves, the screen and G3 of the valve is taken to the centre tap of the filaments.
These little valves will work a treat on your little circuit and will give an output at an HT as low as 18 volts.
They are great little valves for experimenting with and I'm about to embark on an FM radio project using Super-regen, not sure if it will work but I don't really see why not.
I'll still try to draw out a couple of circuits but I do it the old way with pen and paper.
