Loadlines for Parallel SE outputs

[Richard Ellis]

I'm putting together this PSE amp using the 12B4 doubled up running into an OPT at 2500 ohms. With only 170VDC for my B+, I get a really 'steep' loadline for the 12B4......my question is 'How does one do the DC loadline for "twin" ouput tubes.??? I,m trying to get a handle on how much current each channel will be drawing.



________________________________________________________Rick.......

 

[DUG]

Double your load impedance at half the total quiescent current.

Each tube will see half the total current and will only have to drive half the load: 2500 * 2 = 5000 ohms

The transformer will still operate at the same quiescent current.

Makes sense?

 

[jazbo8]

Slightly OT, how does one go about calculating the bias for three DIFFERENT power tubes in SE, like Palmer Triple SE

I think the OPT has three separate primaries, so each tube type could see the correct impedance, is it just that simple?

Jaz

 

[DUG]

How the Palmer Triple SE works is your guess as much as mine.

Could be all three tubes work the same way with similar bias points...or maybe that is the only change between the three...different cathode resistors.

Let us know what you find out.

🙂