Ok to run only 2 KT88s in Fender Twin

[kka]

Would it be ok to run just 2 KT88s (1 on each side) instead of 4x 6L6s ? The PT should easily be able to supply heater current. What other mods would have to be done? Screen resistor to what value?
The speaker output impedance will change too, I assume from 4 Ohms to 8 Ohms, but that I'm not worried about.

This is an old Twin from late 60s without MV.

Thanks for the help.

[Chuck H]

You seem to have your answer already. With only two tubes the filament current is fine. The ideal output impedance will change from 4 to 8 ohms. So, a pair of 16 ohm speakers in parallel. a pair of 4 ohm speakers in series, allow the mismatch or change the OT to match a pair of big bottles to the speakers that are in the amp.

[kka]

Thanks Chuck !

[imaradiostar]

I would seriously consider increasing the screen resistor value- perhaps 1k 5 watt as a starting point.

Expect lower output than you had previously.

jamie

[kka]

Great advice, Thanks