[Amps] 8877 filament.

[MU 4CX250B]

>  A chinese 8877 is the ticket.   Only drawback is the 3 min fil warm up.

The 8877 is a fabulous tube, but there are times when the warmup delay
seems like an eternity. I wonder how much the warmup delay would be
shortened if the filament was run at, say, 3 V on a 24/7 basis, and
then increased to 5V when the amplifier was powered up? The power
expended during the "off" times would only be about 20 W (no ext
cooling required) and my instinct is that the operating life
expectancy of the tube would not be lowered, and might be extended.
73,
Jim w8zr