artosalo,
You are correct. Even worse than Ultra Linear mode. That is why Tetrode and Pentode operation with the screen voltage the same as the plate voltage is something I would never do. Try that with a 4-65 Tetrode at 1500V and get slapped on your wrist by your boss.
Instead, I would always have the screen at a far lower voltage than the plate voltage.
You are correct. Even worse than Ultra Linear mode. That is why Tetrode and Pentode operation with the screen voltage the same as the plate voltage is something I would never do. Try that with a 4-65 Tetrode at 1500V and get slapped on your wrist by your boss.
Instead, I would always have the screen at a far lower voltage than the plate voltage.
It depends on tubes. Some were born with rare rugged screen grids to work on the same voltages as anodes.
artosalo,
Nice schematic and graph. That is a good mode that will work very well for music.
Do not do any square wave testing with that amp that is also mistakenly turned up to clipping levels. 50% of the time the screen will be at 75mA. 0.5 x 0.75 x 270 = 10 Watt screen dissipation on a 2.5 Watt screen (5 Watt screen on 6L6GC).
Do not put a 6L6, 6L6G, 6L6GA, or 6L6GB in a circuit that was intended to be used with a 6L6GC which has 400V or 450V on the screen that is either in Pentode or Ultra Linear modes.
Nice schematic and graph. That is a good mode that will work very well for music.
Do not do any square wave testing with that amp that is also mistakenly turned up to clipping levels. 50% of the time the screen will be at 75mA. 0.5 x 0.75 x 270 = 10 Watt screen dissipation on a 2.5 Watt screen (5 Watt screen on 6L6GC).
Do not put a 6L6, 6L6G, 6L6GA, or 6L6GB in a circuit that was intended to be used with a 6L6GC which has 400V or 450V on the screen that is either in Pentode or Ultra Linear modes.
The 807 was one of RCA's most robust Beam Power (RF/Audio) Tubes. It is not exactly a 6L6, and not exactly a 6L6GC. But the complete family of 6L6s are also Beam Power Tubes; (unlike the EL84 and EL34 that are true Pentodes).
I can not read Russian, so I can not determine much about the 6P3S-E.
We all have departed from Tyimo's desire to use 6P3S in triode mode, 300Vp, and with 70mA Ik (Ip + Screen = 70 mA). It was said he would only get 5 Watts that way.
Then some of us (me included) went to other modes, and more power, and other directions. Maybe 5 Watts is enough for Tyimo.
And we are all far from the original posting.
I can not read Russian, so I can not determine much about the 6P3S-E.
We all have departed from Tyimo's desire to use 6P3S in triode mode, 300Vp, and with 70mA Ik (Ip + Screen = 70 mA). It was said he would only get 5 Watts that way.
Then some of us (me included) went to other modes, and more power, and other directions. Maybe 5 Watts is enough for Tyimo.
And we are all far from the original posting.
Good discussion though. Perhaps a mod can split the thread or something...
I don't read Russian either, but there are numbers and simple patterns for me to figure out that катод means cathode etc... Google Translate is helpful, too. The android app will let me translate a picture in real time.
I don't read Russian either, but there are numbers and simple patterns for me to figure out that катод means cathode etc... Google Translate is helpful, too. The android app will let me translate a picture in real time.
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6П3С and 6П3С-E are structurally very different, as can be seen from the photo. Also the plate characteristics are different. 6П3С is much like 6L6G while 6П3С-E is long life type having specifications with tighter tolerances.
An externally hosted image should be here but it was not working when we last tested it.
Some seem to have common perception that a few tens of volts more than manufacturers limit, would cause a full destruction almost immediately. This idea is maybe from tweaking with transistors etc. But this is not the case with tubes. For example some sweep tubes have quite low Pd_max. specs, but actually can live very long with much higher load. Some types have long life versions with lower voltage and power limits than their "ordinary cousins". For example 12E1 vs. S11E12.
The KT120 filament dissipates up to 12.3 Watts.
The Max DC cathode current is 250mA.
The plate is good for 60 Watts.
The 6P45S filament dissipates up to 17 Watts (5 Watts more than the KT120).
The Max Pulse cathode current is 800mA (550mA more than the KT120 DC rating).
The plate is good for 35 or 40 Watts.
These tubes are very different, including the voltage ratings too.
The Max DC cathode current is 250mA.
The plate is good for 60 Watts.
The 6P45S filament dissipates up to 17 Watts (5 Watts more than the KT120).
The Max Pulse cathode current is 800mA (550mA more than the KT120 DC rating).
The plate is good for 35 or 40 Watts.
These tubes are very different, including the voltage ratings too.
Many people say 6P3S is = with 6L6GC.
Svetlana has SV6L6GC tube.
It is a 30W tube.
http://www.tec-sol.com/products/tubes/svetlana/6l6gc.pdf
Svetlana has SV6L6GC tube.
It is a 30W tube.
http://www.tec-sol.com/products/tubes/svetlana/6l6gc.pdf
There are more than one 6P3S data sheets.
The one at Frank's electron Tube Data sheets is quite unreadable.
Try this 6P3S data sheet:
http://www.teslatron.pjweb.cz/obrazky-filemanager/russian-6p3s-e.pdf
I interpret that data sheet: The 6P3S and 6L6GC are Not equal.
The one at Frank's electron Tube Data sheets is quite unreadable.
Try this 6P3S data sheet:
http://www.teslatron.pjweb.cz/obrazky-filemanager/russian-6p3s-e.pdf
I interpret that data sheet: The 6P3S and 6L6GC are Not equal.
Here you can find large 6P3S and 6P3S-E data:
http://www.rutubes.com/articles_for_description/datasheets.htm
http://www.rutubes.com/articles_for_description/datasheets.htm