Having repaired the Pete Millett’s interface (hopefully) I tested two 26 DHT triodes I had at hand. One was an used Hytron ST valve and then the other test was an NOS White Whestinghouse ST valve, which is actually in pristine conditions.
Both valves were tested with the same operating point:
- Vg=-10V
- Ia=5.5mA
- input signal adjusted to produce Vo=10Vrms (+22.22dBu)
Well, I think I have re-vindicated the 26 DHT THD performance at a decent swing. Surprised to see the WW valve achieving 0.03% THD.
