Ok.. I'm a little confused.
The hybrid-a schematic says 1K for the screen grids, but someone here on the forum said that 470 was often used. Is that correct? Soe say 5W is needed, other say 3W is ok. I might go for three 2.7K 2W in paralell for now, and get some 5W later...
Also, the 1 ohm resistors for the cathodes, how many watts should they be to be on the safe side? I have some 1W, and possibly some 2W that I inteded to use....
Tommy
Screen grid and cathode values again?
Moderators: pompeiisneaks, Colossal
Re: Screen grid and cathode values again?
Screen resistors, because they're soldered directly on the tube sockets are exposed to a lot of heat. Most folks use the big cement 5W resistors but in reality you can get by with as small as 1 watt. Your plan should be fine.Tdale wrote:Ok.. I'm a little confused.
The hybrid-a schematic says 1K for the screen grids, but someone here on the forum said that 470 was often used. Is that correct? Soe say 5W is needed, other say 3W is ok. I might go for three 2.7K 2W in paralell for now, and get some 5W later...
Also, the 1 ohm resistors for the cathodes, how many watts should they be to be on the safe side? I have some 1W, and possibly some 2W that I inteded to use....
Tommy
The cathodes, calculate the power and you'll see that 1 watt will be fine, but again there's the heat issue so you're better off with larger. Use 1% tolerance because you'll be biasing using this resistor and need accuracy.