Determining optimal OT turns ratio

[oshifis]

Yves,

It is a typo indeed, the core area is 25 cm2. You have a good point about the Vg2 swing. What do you suggest then?

Laszlo

[hemgjord]

You will have to go down in turns no for the screen winding. This will result in a UL connection but still with separate B+. This should be good for quite some power since you could run the plates at 600V while still keeping the screens below 300.
I know this has been made but i don't seem to find any references right now.
Yo probably have to check the maths to see if screen dissipation is still safe and if the usual approx 40% turns ratio for UL still holds with different voltages on plate and screen.

[2004ex]

Originally posted by lt cdr data
...generally, hi primary Z gives low distotion and low power, low Z gives hi dist and power...

Just found this from a James Transformer dealer's website:
Freq Response at -2 dB (Single Ended 6123HS)
18Hz~67Khz @ 2.5K
18Hz~64Khz @ 3.5K
18Hz~53Khz @ 5K
So can one say that "low Z wins in frequency response and power, but loses in distortion"?

[oshifis]

The reason could be the higher capacity of the high-Z primary winding.