That's the suggested OP for triode. Svetlana doesn't make 6P3S tubes. Foton and Reflector mainly. The Soviet datasheets don't include triode data, but as I said it's a 6L6 (not GB,GC) clone. The STC datasheet gives triode information.
http://www.tubezone.net/pdf/6l6g-stc.pdf
http://www.tubezone.net/pdf/6l6g-stc.pdf
Last edited:
Bias voltage will vary from tube to tube. If you're not using cathode bias, you need to adjust the bias voltage while checking the current. For what it's worth, I've built amps with 6P3S in triode and in regulated tetrode. The "typical" datasheet implementation for class A push pull will give you 15W and still have quite low distortion.
Thanks for this. One day I'll learn how to use SPICE instead of just building and testing the circuit. Can you adjust that SIM for 400V? Does it make closer to 10W?
Be careful of what tube you use: voltages, currents, and dissipations you run them at.
Maximum plate dissipation and Max screen voltage are not all the same for those tubes.
Pentode/Tetrode operation with screen voltage less than plate voltage is one thing.
Triode wired operation is another.
artosalo's suggested operating point: 400V x 58mA = 23.2 Watts
6L6 metal, 6L6G, 6L6GA 19 Watts plate screen 270V
6L6GB 19 or 22 Watts plate (depending on manufacturer) screen 270V
6L6GC 30 Watts plate screen 450V (these have the most capability)
6P3S and 6P3S-E . . . check the data sheets before deciding on the voltages and currents you run them at.
Maximum plate dissipation and Max screen voltage are not all the same for those tubes.
Pentode/Tetrode operation with screen voltage less than plate voltage is one thing.
Triode wired operation is another.
artosalo's suggested operating point: 400V x 58mA = 23.2 Watts
6L6 metal, 6L6G, 6L6GA 19 Watts plate screen 270V
6L6GB 19 or 22 Watts plate (depending on manufacturer) screen 270V
6L6GC 30 Watts plate screen 450V (these have the most capability)
6P3S and 6P3S-E . . . check the data sheets before deciding on the voltages and currents you run them at.
As I said, 6P3S work for years at that level. 20W Plate + 2.75W screen = 22.75W... 23.2W is not a large stretch from there. Obviously, if you run them at a lower Pd they will last longer. Agreed though, some specs should be respected... Some can be flaunted. To be honest, the only tubes I've have screen failure have been Chinese 6550 or KT88.
Last edited:
kodabmx,
Good point.
Lots of tubes will run at higher levels than they are rated for.
How about some guitar amplifiers; and they are driven very hard.
Music:
Pentode/Tetrode with screens at lower voltages works well because the plate does not go below the screen voltage for very long, and only at loud passages.
Triode wired, the plates never go below the screen voltage, no matter the signal level.
Ultra Linear, potentially the most abusive mode.
The screen voltage starts higher than the plate voltage (OPT DCR voltage drop).
The screen voltage only falls at 40% of the plate falling rate.
The plate voltage goes far below the screen voltage really fast.
Ugh!
Good point.
Lots of tubes will run at higher levels than they are rated for.
How about some guitar amplifiers; and they are driven very hard.
Music:
Pentode/Tetrode with screens at lower voltages works well because the plate does not go below the screen voltage for very long, and only at loud passages.
Triode wired, the plates never go below the screen voltage, no matter the signal level.
Ultra Linear, potentially the most abusive mode.
The screen voltage starts higher than the plate voltage (OPT DCR voltage drop).
The screen voltage only falls at 40% of the plate falling rate.
The plate voltage goes far below the screen voltage really fast.
Ugh!
