Tube CAD?

[Hojvaelde]

Hey

I bought Tube CAD and have started to play with it. Are designing LTPS with 6N7 and 6SC7 tubes.
I have a question which I can not find the answer.
The 2 components in the red circles, they must surely be determined by the used tubes? Rules of thumb are received with pleasure.

Regards

Benny

[tubelab.com]

The 1M resistor just makes sure that the two grids are at the same DC potential. In the perfect world it could be a very high value. With real tubes that might draw grid current 1M is OK, I usually use 470K. Its value determines the input impedance of the amp at low frequencies. Miller capacitance has an effect as the frequency goes up. Choose any value you like from say 50K or so up to 1 meg, even higher with quality tubes.

The capacitor sets the low frequency point of the amp. It forms a pole against the resistor discussed above. Below the corner frequency the LTP will become unbalanced. Since it is in effect part of the audio path, use a decent quality cap. Cheap stuff makes for some unpredictable sound artifacts. I found this out the hard way. I usually use a .1uF. A really large cap, 1uF or more can make the stabilization time long.

[kevinkr]

+1