HT rectification

[ok_state_blues]

Quick question. While breezing through a schematic lately I noticed only 1 diode being used on each leg of a secondary for rectification. Isn't it customary to use the diamond shape of 4 diodes to rectify. This results in a rectification factor of 1.414. But this schematic only shows the voltage being rectified by ~1.284. Could someone explain this to me?

[PharmRock]

This page should answer your question on this.
http://www.valvewizard.co.uk/bridge.html

I've found Merlin's website very helpful on this and other subjects. 

[PRR]

> by ~1.284.

There's losses everywhere. 9% loss is doing pretty OK.

[ok_state_blues]

So that I gather is the diamond shape is used when the PT doesn't have a Center Tap. Conversely the single diode on each leg is used when a center tap is present? Am I understanding this correctly?

[PRR]

https://en.wikipedia.org/wiki/Rectifier#Single-phase_rectifiers

[66Strat]

The 285 Volt AC notation appears to be a No Load voltage reading. Hammond specs the No Load AC to center tap rating for the 290JX as 280.9 volts. The under load voltage rating is 250 Volts at 69ma. Working backwards, 366 volts DC divided by 1.414 ~ 259 AC. The difference between 259 volts AC and 250 Volts AC is likely due to the AC voltage at the wall being slightly above 120 volts.

https://www.hammfg.com/files/parts/pdf/269JX.pdf

[ok_state_blues]

Thank you PRR and 66Strat. I had a feeling I was overthinking things.