12E1 single ended pentode

[wenig watt]

I had already told you about it several times, a very funny amplifier insofar as my friend bernd was on a guitar amplifier trip and wanted to build this design so impractically for stereo.
The thing sounds disarmingly good, but it happily ate tubes. together with the G2 it was almost 44 watts, which led to glowing anode plates. Now we have reduced the anode current by about 10% via the resistor and thus adjusted the maximum output. The power is not noticeably reduced and the sound is a dream. I also now know how to adjust new tubes. In fact, only some tubes started to glow, others worked without complaint. The variation was about 10%. A fine line between good and bad...

Pictures later!

Best regards

Arndt

[simon]

Hello Arndt, Аs can be seen from the data and graphs, 40 watts is
the maximum total power of the anode + second grid.
I assume that it is connected in triode mode?
What is the operating mode of the anode voltage and anode current ?
I am sure that there is a good mode that does not exhaust the lamp quickly,
and yet the amplifier "has power", although when measured, the rms power will show less ...

[wenig watt]

Exactly that! Hence the 10% off. Tubes with 125 mA were good Tubes with 135 mA were glowing. I can adjust the tubes individually (about 14mA). That should fit now. It runs as a pentode. This means that the damping is lower, which makes the sound more open.









Best regards

Arndt