Experimenting on headphone amplifiers, not always turn out the way you expected. Well, that’s the nature of experimentation and some smoke may come along the way.
Here is my new take on the headphone amp. Modified the 2P29L to fit the 6e6p-dr valve. I love this IHT one, so wanted to experiment more.
Instead of the classic HT, I used some Chinese 300-450V SMPS modules. I used the 70W version with success before, not these tiny ones.
Individually tested all parts and worked fine. Fired up the SMPS with the hot filaments and the 6e6p-dr running at 20mA each and the SMPS oscillated. They went to 450V instead of the 250V dialled and one of my cap multiplier PCB boards got damaged. Damn!
Back to the drawing board. I will probably stick to the simple HT supply 🙂