Power Tranny Loading

adamsapple · Post by **adamsapple** » Sat Jan 21, 2006 8:00 pm

What's an acceptable amount of plate voltage drop
btwn no signal and master at 10 conditions? The reason I ask is I put EL34s in a 65 Bassman with a new 3.2K primary OT and the power tranny gets REAL hot (original PT). I didnt notice this heat level before when running 6L6's. I'm only running the EL34s on the PT filament winding (3.0 amps). I've got a separate 2A filament tranny for the pre's so filament overloading should'nt be the issue. When I run 6L6s at full bore I get a plate drop of 40V and max plate current of 220mA with a 200mv sine wave input. With the EL34's I get about a 50V drop with max plate current of 300mA. Both the 6L6's and 34's were biased at 35mA idle. Do EL34's naturally suck up more power than 6L6's when maxed? Is 40+ volts of drop thru the PT a bad thing? I've never read about needing beefier PT's just to run EL34's (aside from filament current issues).