Pleiades Electra 3 with 10MΩ from anode to grid

Caution: protect your ears from high sound pressure levels.


One EF183, triode connected for each channel driving the Sennheiser HD580.


Vb=12V.


Both Rag of 1.5MΩ and 10MΩ sound spectacular. 10MΩ should be of less power. In the first case the DC anode current through headphones is 2.5mA and in the latter case 1.5mA.


How would ECC88 sound with this amplifier?