kt 120

[Andy Le Blanc]

what you see is the increase of plate dissipation levels.
for conservative designs, 35w/6550, 40w/kt88, 50w/kt90, 60w/kt120

I like the tone of using that increased plate dissipation in that manner...

I've use a 1.7k @ 4/8/16 and mismatched to reflect 3.4k on the primary
the watt rateing was the question, I saw that 50 and 60w opt had twice the current rating per side of the ct and wondered if it were wise

[Andy Le Blanc]

hammond 373hx looks like the one, http://www.onlinecomponents.com

anybody use them yet... they have them for around $170

[Andy Le Blanc]

best yet for power... hammond 278cx

actually in stock at tubes and more, that helps, $120
$135 at parts express
$124 at angela

The real issue becomes the heater winding, KT120 have a hefty fil. current.
The 278cx has a 6A heater winding, twin PT often have 5.5A for the heaters,
kt120 could have as much as a 1.95 draw according to the sheet, a pair could leave only 2A to the pre.
The V is higher 800 ct., 535 ma., should land me around 560 plate.
That will address the low voltage pessimism and meets my design wish,
barley taxing the supply at static condition at design max dissipation.
The rail voltage should fall within screens 600v limit.
It seems really flexible, with the exception of tube rectifier, its a common and affordable part.

It puts the major investment for pt, opt and tube set around $350