[Lewis]

Hi,
My understanding of tube rectifiers is somewhat limited, and I'm hoping
to get some help here.

I've seen the basic schematic of a four-pin full-wave tube rectifier
depicted at least two ways, and I'm confused. I've seen it this way:
http://oldradio.qrz.ru/tubes/foreign/01/5Z3.gif
In this configuration, what is done with the center tap of the 5V winding?

I've also seen it where the B+ appears to be taken from the center tap
of the 5V windings, like http://www.anthemav.com/OldSitev1/pdf/taste.pdf
(page 28)

Assuming both of these are acceptable, which is preferable and why?
Thanks,
Lewis