A discovery...or am I mistaken...?

[eleventeen]

To achieve a nominal B+ voltage from a too-low-volts power transformer with no CT, a voltage doubler is indicated.

On a salvaged power transformer from a full-wave set (like an old TV power transformer) it's pretty much a given that you'll not find a bias tap, hence you'd normally take a leg of the HV secondary, throw in a reverse diode, work out a sufficent dropping resistor, and make your negative voltage.

But you cannot do both!

You can't grab one of the HV output legs of a non-center-tap power transformer and make a bias supply using a reverse-biased (eg; "backwards") diode IF your B+ circuit is a voltage doubler.

In other words (or symbols, actually) THIS WILL NOT WORK! 

[Ritchie200]

Can't you just pull it of the leg before the doubler?  Or am I mistaken!  Someone else weigh in please!
Jim

[Dave]

Any of the Bogen CHB amps did it.

Dave

[eleventeen]

Dave, you're absolutely right. I knew it had been done somewhere. Must be that .22 cap separating the voltage double from the bias section.

http://schematicheaven.com/hifiamps/bogen_chb100.pdf

^^^^^^^^^^^
Update: It worked!

[bluesbear]

This looks like a job for cathode biasing!
Dave