Could it be that the voltage differential is smaller?
Oops, just saw that Kevin mentioned this already.
One strange thing about 4P1L is, it is very linear in triode mode, while in pentode mode screen grid draws relatively high current. Like, Germans designing it's prototype RL2,4P6 took some triode project adding extra grids.
Here is interesting web page: Google Translate
Here is a picture from there:
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Anatoliy, any idea why there might be an envelope within an envelope? Could it be for high altitude use? 😀
He made it for a vintage radio, to match shape and size. I once saw "golden" 6SL7 with soldered inside 6N17B-V tube.
In the gyrator circuit I suggest a capacitor from the wiper to ground. It’s also possible off course to take the output from the anode instead of Mosfet source. Listen to what is best sounding.
Peter
Peter
I drive them in output stage up to +12V on G1, with 5K load each. 2 in parallel, 2.5K load, +250V B+, 5W output.
Hi,
Those curves are for pentode mode and I'm planning to run the valve in triode mode. Have plotted the triode curves before but don't have them here right now. On previous distortion measures some of us found that THD was minimised at 80V and 25mA. Haven't tried how it sounds at different op points yet....
I will etch the PCBs over the weekend if I get some time
Hello, I don't translation many. This tube in triode mode is good, but out power smaller . I is opinion by VA characteristic. But and pentode mode is super (S1=S2).
aeandm
Attachments
I was getting, as I said before, 5W from 2 tubes in parallel, in triode mode. Load was 2K4, that means about 5K per tube. However, I was driving them with cathode follower, up to 12V positive peak. For preamp that is discussed in this topic such power is not needed, so the higher is dynamic load resistance, the less distortions you are getting from it. That's why we discuss gyrator load here.
Let me translate for you, if you have troubles reading English.
Без проблем. 🙂
Hi-fi + semiconductors = High-End. I mean real high end, not fetish. Of course, if to use semiconductors to preserve each bit of smoothness of transfer functions of tubes.
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HI-FI с полупроводниками не понимаю! Максимум ЦАП и фильтр(?),
После того как послушал настоящий HI-FI.
Fetish is 10K $
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It's ok to write in another language, as long as someone translates it. Thanks!
He says, he does not understand tubes with semiconductors after he heard real Hi-Fi. What he accepts, semiconductor DAC and probably filter.
Thanks God, he does not use Ukrainian that I understand a little bit only... 😉