What circuit to build with these transformers?

[mozz]

SE? PP? Not enough current for PP 6v6? El84 types heard they do not sound good in SE. I do have some 7189A's that could take 440v, SS rectifier, 90ma might just make it for a pair? I have lots of output transformers to choose from so no problem there. Shows 105 ma at 400v max signal.

[PRR]

El84 types heard they do not sound good in SE. I do have some 7189A's

How many Valve Juniors did Epiphone sell?

I do have some 7189A's

7189 is a 6BQ5/EL84 made with 400V plate stuff. Doesn't change the tone.

[HotBluePlates]

SE? PP? Not enough current for PP 6v6? ...

700v CT ---> 350v x 1.414 = 495v peak
   - You'll want that 5Y3 rectifier, and maybe some extra dropping resistance if the PT doesn't already have that as excess winding DCR.

  - Pencil "450v DC" supply.
  - 6V6 should be able to pull its plate down to 100v, so 450v - 100v = 350v peak swing.
  - Reserve "10mA" of PT capability for small tubes, screens:  90mA - 10mA = 80mA.
  - Convert to peak current:  80mA x 1.414 = ~113mA
 
  - Does our peak voltage and peak current imply a probable output transformer?
      - Impedance = Volts / Current = 350v peak / 0.113A peak = ~3100Ω
      - For Class AB, Ra-a = Impedance x 4 = 3100Ω x 4 = 12,400Ω.
      Let's round-down to a more-common 10kΩ OT primary impedance

  - Can a 6V6 pass 113mA peak with 400v or more on the screen?  Yes, that should be easy (based on a brown Deluxe, Deluxe Reverb).

  - Power Output = [Peak Current² x (Primary Impedance / 4)] / 2 = [0.113A² x (2500Ω)] / 2 = ~16 watts
  - Plate Voltage Swing: 0.113A x 2500Ω = 282.5v ---> 450v - 282.5v = ~168v lowest plate volts (before sag)

... I have lots of output transformers to choose from so no problem there. ...

Got a 10kΩ primary at 10 watts or more?

If not, Hammond has the 1609 which looks like a perfect fit.  Yes, Hammond says "10 watts" but they also rate it down to 30Hz.  Since you won't be going that low, you can shove more power throughput, making 16-20w no problem.

If the Stancor actually delivers a little higher current than the rated 90mA, then you'll get more than the estimated 16w output power from this setup.  The Stancor Catalog (page 14) says to use this PT with a choke-input power supply, in which case it will deliver 350v x 0.9 = 315v DC ---> better suited for EL84 and 6AQ5.  It is wise to use a choke rated over the claimed 90mA capability of the PT.

You can pick parts other than what I outlined, and get a bit less output power.  These days, most folks don't want "all the power/loudness."

[tubeswell]

I'd take a chance with that PT in an early tweed deluxe circuit

[mozz]

 I came across 3 of these transformers. Forgot i made this test unit 10 years ago to test pulls. 3 resistors, about 22uf/600v in there. With a good 5Y3, i get 434v @46ma, 412v@65ma, 362v@116ma. So, nothing too outrageous. Weak 5y3 was about 40v lower at highest draw.  I have made a few 5c3,5d3,5e3, princeton reverbs, etc. So maybe a brown/deluxe this time. No 12.4k output transformers but a few 16 ohm speakers sitting unused so maybe slap that on a 6.6k or 8k transformer, if needed/5ar4. Now out to the garage to find that empty/heavy Acoustic cabinet with 12" speaker cutout.