On Thu, Feb 20, 2025 at 05:40 AM, Andy I wrote:
There is some feedback from the audio signal into the heater voltage. Was that intentional?? Or just an undesirable side-effect?? I don't expect it would have very much effect on the heater's temperature (and from there to the triode's characteristics), but it looks undesirable to me. Should there be filtering?
Sorry, are you asking whether the audio signal feedback into the heater voltage comes from a design intentional choice ? Actually I don't know since I took it from the schematic of a commercial audio amplifier (Bravo Ocean).
Carlo