Can anyone point me in the right direction? I am trying to learn how to regulate screen voltage and switch it off and on. Any suggestions on where i should go to read up on or a good book that might help?
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Tetrodes
- Thread starter Crusher
- Start date
How much voltage? Most use a series string of OA2 or OB2 or similar regulator tubes. Cheap and easy regulation for a screen supply. You could get the GM3SEK tetrode boards but they are not cheap, running around US$208.00 each plus shipping.
was thinking about a 4cx3000 or 6000 or something. even maybe play with 250b or similar. I have worked with triodes but almost nothing with tetrodes. So this is new for me. Know regulated is the way to go.
The lower power tetrodes in the 4cx 150 to 400 family all use about 350 volts on the screen.
In these circuits a string of Zeners to add up to over the screen supply voltage is often used to regulate and drop the input voltage to the level desired.
The output of the supply at the screen often uses a load resistor to preload the supply.
A good amount of filter capacitance will also help keep the supply stable under SSB use.
In many amplfiers using tetrodes, the plate voltage is switched on full time and the screen supply is switched on and off for keyup application along with the T/R relay.
I have just such an amplifier that used a 4cx250 and now rettrofitted with a Russian GS36B that is essentially the same as a 4cx400.
Plate (anode) voltage is 2400.
The amplifier was at the 320 watt output level on 6m, now is 600 watts out.
The amplifier had a very large power supply so was no issue using the higher power tube.
Any tube in this family will plug in as all have the same pinout.
Of course the cooling is by "forced" air not just a fan.
Good luck.
In these circuits a string of Zeners to add up to over the screen supply voltage is often used to regulate and drop the input voltage to the level desired.
The output of the supply at the screen often uses a load resistor to preload the supply.
A good amount of filter capacitance will also help keep the supply stable under SSB use.
In many amplfiers using tetrodes, the plate voltage is switched on full time and the screen supply is switched on and off for keyup application along with the T/R relay.
I have just such an amplifier that used a 4cx250 and now rettrofitted with a Russian GS36B that is essentially the same as a 4cx400.
Plate (anode) voltage is 2400.
The amplifier was at the 320 watt output level on 6m, now is 600 watts out.
The amplifier had a very large power supply so was no issue using the higher power tube.
Any tube in this family will plug in as all have the same pinout.
Of course the cooling is by "forced" air not just a fan.
Good luck.
- No one is chatting at the moment.
