[Phil Allison[_3_]]

"Phil Allison"


** More testing with the FFT feature on a Rigol scope:

3H is dominant from about 9 watts through to 21 watts.

From 1watt to 4 watts, 2H dominates, then 4H, then 3H.

If load R is changed to 16 ohms, 2H dominates all the way.

2H cancellation is occurring over a fairly wide range, but it is not
complete.

I can swap the 6SN7 with almost no change.


** One final test result:

300Bs removed, 10:1 scope probe on grid pin, input 260mV rms to 6SN7.

2H = -24 dB = 6%

3H = -42dB = 0.8 %.


..... Phil