Virtual center tap, elevated at power tube cathode

[Johnrcurry]

I am working on a project based on the 5f2a Princeton circuit using spare parts I've accumulated over time. I am using a 6x4 rectifer tube (my power transformer has a 6.3 volt filament winding but no 5 volt filament winding), a 6aq5 power tube and a 12ax7 preamp tube. The PT has no center tap so I plan to make virtual center tap with 100k resistors and elevate the heaters at the power tube cathode.

My question is this. . . . In order to shorten and simplfy wiring, can I do that right at the power tube socket (as in the attached drawing)? Is there any disadvantage to wiring it this way?

Thanks

[pdf64]

No problem with that, though 100k is way too large, 100 ohms is the usual value.

[Johnrcurry]

Thanks. And you're right about the "100K". That was my misprint.

John

[pdf64]

Actually, I'm not sure that given the dc elevation, creating a virtual center tap would provide any benefit over just connecting one side of the heaters to the cathode.
Could you try it both ways and report back?

[Johnrcurry]

When I get to actually building this amp I can try it both ways and report back. But I'd like to understand your thinking on that. Why would connecting one side of the heaters to the power tube cathode yield the same result as an artificial center tap?

Thanks

John