valve question for steve

[django]

Hi Steve-i installed 4 new kt66 in my 2466 today.When i set the valve bias to 74ma and check the negative grid voltage at pin 5 of the power valves it is way off the -62 to -64 v range.I have to bias the valves to about 115ma per side to reach the negative grid volatge i get with my previous valves.Please can you tell me are the new valves(direct from marshall) faulty as i dont know which bias reading to trust-either milliamp reading or the neg grid voltage?

[SteveD]

Welcome to the forum django.

The valves come in ranges of transconductance. Your last set may have been matched at a lower value whereas your new set may be higher. Go by the mV (mA) reading at pin 1 and pin 3 at CON10.

[django]

Cheers Steve and thanks for the amp i've always heard in my head but can now play through my fingers.