02-08-2015, 08:59 AM
(This post was last modified: 02-08-2015, 09:05 AM by pwdrive.
Edit Reason: boo boo
)
I agree with the comments so far regarding shorting/grid bias/cathode etc.
It might be worth while finding a transformer with the following secondaries, 250v-0-250v, (or 0v-250v) + 6.3v ct, & 5v, the heater windings would give a bit more flexibility for the pot derated power values for 2v and 4v valves, you should be able to find a transformer with those secondary windings, 5v winding was common for rectifier heaters.
The grid bias could be obtained from the 250 volt winding, eg: halve wave rectifier, filter, dropper, 30 volt zener with the bias pot connected across it.
Lawrence.
It might be worth while finding a transformer with the following secondaries, 250v-0-250v, (or 0v-250v) + 6.3v ct, & 5v, the heater windings would give a bit more flexibility for the pot derated power values for 2v and 4v valves, you should be able to find a transformer with those secondary windings, 5v winding was common for rectifier heaters.
The grid bias could be obtained from the 250 volt winding, eg: halve wave rectifier, filter, dropper, 30 volt zener with the bias pot connected across it.
Lawrence.
