[Milsurplus] need info 440hz xfrmrs and OS-10/U

[Unserviceable but Repairable]

Patrick you wrote

} One thing I have learned is that the turns per volt on higher frequency 
} transformers can be much lower

I tried using a 12VCT 60hz xfrmr as a substitute for a '56 Merc
vibrator xfrmr once thinking that the case.  Vibrators run ~115hz.

Darn if it didn't work fine & it still does.  Of course I was degraded
for not doing the 'accepted.*'  Buying a solid-state vibrator & a 
re-wound xfrmr.

Talked job up to a degreed expert & he sed if you double frequency, you
double a transformer's allowable voltages.  Thinking now I'm sure the 
inductive reactance formula rules

              Xl = 6.28 * f * L

IE, if you halve the inductance (halve 'turns/volt') & double the f,
Xl (in ohms) unchanged.

About the same time I made a gizmo to produce 400hz @ 20W for a 180T/CU991
Collins beaut.  Did a 60hz 24VCT 2A xfrmr bridge-rectified into a Sanken
hybrid 50w amp module driven by a XR2206 sine-wave generator & a NE570
variable gain cell.  Sanken runs a 400hz 6.3V 10A to 110V surplus xfrmr
back-connected.  Like you, output V rectified & adjusted as input to NE570
for regulation feedback loop.

Not too many parts but I don't think as elegant as your described
driver-emitter feedback loop for the 3055 output banks

> Sorry to drone on, but I've had alot of fun with 400hz stuff.

Me too - & matching theory w. results always turns out an 'xtra kick.'

  Marty

*another example.  I've run a Johnson 500 for years w. 2 paralleled
 matching microwave oven xfrmrs into a bridge - 2 diodes 866s, two SS.  
 Oven xfrmrs 'way below point where mag shunts 'kick in' & J500 goes like
 a ring in a bell

 BUT

 Have to float oven xfrmrs on plexiglass since one side of HV secondary
 is grounded.