Need a new PT, overbiased EL34?

[bluefoxicy]

Hey all. I know nothing about electronics.

I've modded up a single-ended class A amp that runs a 12AX7 into EL84 to take an octal tube, which wants a 25W bias. Now I'm running a 12W EL84, 25W I can make happen; however, the PT will catch fire. PT is 35W power draw, 260VAC and 6.3VAC

I need to run a 12AX7 6.3V@0.76A filament, and can probably get away with that on the EL34L but really it wants 6.3V@1.5A.

As far as I understand (I NEVER get straight answers from EEs, they'er like "duh look at the impedance on the components" and I'm like "A filament IS NOT A COIL DAMMIT"), if I grab 6.3V@2A filament leads and jack it into the filaments in parallel, the 12AX7 will keep the same voltage and resistance and draw the same current (0.76A); the EL34 will draw 1.5A.

By this logic, I need 260VAC on the PT and 6.3VAC@(>=)1.5A on the filament output. So I'm looking at a Hammond HX-270DAZ on RadioDaze, 76VA (wattage?), 260-0-260 secondary (I guess that's 260VAC), 6.3V@3.5A available off the filament coil. I can figure out what to do to the circuit to control the current draw (shouldn't be too involved). Good enough?

http://radiodaze.com/hammond01.htm

[Bruce / Mission Amps]

Hey all. I know nothing about electronics.

I've modded up a single-ended class A amp that runs a 12AX7 into EL84 to take an octal tube, which wants a 25W bias. Now I'm running a 12W EL84, 25W I can make happen; however, the PT will catch fire. PT is 35W power draw, 260VAC and 6.3VAC

I need to run a 12AX7 6.3V@0.76A filament, and can probably get away with that on the EL34L but really it wants 6.3V@1.5A.

As far as I understand (I NEVER get straight answers from EEs, they'er like "duh look at the impedance on the components" and I'm like "A filament IS NOT A COIL DAMMIT"), if I grab 6.3V@2A filament leads and jack it into the filaments in parallel, the 12AX7 will keep the same voltage and resistance and draw the same current (0.76A); the EL34 will draw 1.5A.

By this logic, I need 260VAC on the PT and 6.3VAC@(>=)1.5A on the filament output. So I'm looking at a Hammond HX-270DAZ on RadioDaze, 76VA (wattage?), 260-0-260 secondary (I guess that's 260VAC), 6.3V@3.5A available off the filament coil. I can figure out what to do to the circuit to control the current draw (shouldn't be too involved). Good enough?

http://radiodaze.com/hammond01.htm

A 12AX7 at 6.3v draws only 300ma of filament current. The EL34 is 1500ma and the EL84 is 760ma.
If your PT is well made and worth a grain of salt, rated at a real 6.3v@2a with a 100% duty cycle, you might be able to run all three at around 2.6a.
...and of course, the other will run forever is it is rated at 6.3v@3.5a.

Other then that I can't quite figure out what you are asking because you won't be controlling the current as the filaments will only draw what they need.

[bluefoxicy]

Other then that I can't quite figure out what you are asking because you won't be controlling the current as the filaments will only draw what they need.

I know zero about electronics, this was probably the missing piece of the puzzle.