12AU7,12B4A PSE schematic needs finishing!

[Richard Ellis]

OK...I have acquired a slug of tubes & this is what I came up with, A two stage Parallel SE using 12B4As' paired up and a single 12AU7....The power section I pirated from an existing schematic using a single 12B4A...paired up for more than 1.5 Watts...upping the power to 3 Watts. It is the 12AU7 I need to calculate....according the the loadlines i've scanned over, I can run nearly to zero for the biasing. Perhaps -2V....don't want to run close to Zero.
Undoubtedly programs exist out there....."in the cloud" whereby someone can plug in the schematic & get some values in the .245 Sec................if not I'll just get out a dozen clean sheets of paper & start drawing out some loadlines off the curves.

__________________________________________________ ________Rick...........

[jerluwoo]

Here's a design that should work well. Not sure what schematic you lifted the output section from but 1.5 watts doesnt seem realistic without running the tube well above spec. At least thats what the load lines indicate. This design will get you a fairly clean 2.2-2.4 watts, and the 12B4's are within spec.

[Richard Ellis]

Well......heres the TX 'we' have available down here.A 200-0-200 150mA, 3.15-0-3.15, 5V @5?A. And some 6W, 2500-Ohm SE TXs'. Its a local house in Buenous Aires..............where I found a relative who had a stash of tubes.
A bunch of 12AU7s'...(5?) and some 5U4 rectifyers. See "Bag-O-Tubes"..

I have een modeling some PS with Duncans program...trying to nail 200VDC........by the way, how much current will your schemo draw??? So I can plug in the values on Duncan PS ...I have a pair of 200V, 470uF, paired up to 400VDC, with some 470Ks' for balance & bleeding.

Thanx a bunch.

__________________________________________________ Rick..............