[Milsurplus] Any Tips on How to Drop the AC voltage to the Primary of a Power Transformer?

[Mack]

I need to drop the AC input voltage to a power transformer to get the output voltage where I'd like it to be. I need to drop 120VAC to 85 VAC at .75A under no load conditions. I'm currently using a variable transformer to regulate the input voltage but would prefer a solution that is MUCH more compact so it would fit on the power supply chassis. I tried a household fan and incandescent controller but the high inductance of the transformer primary causes the fuse to always blow using this technique.

I've considered using an approx 46 ohm 40W resistor but I'm not sure about the voltage regulation under intermittent (CW) load. Are there any better techniques than those I've described here?

In case you're wondering about the project: It's my current ARC-5 receiver, transmitter, modulator restoration. I'm using one power supply for all three pieces. The only HV transformer I had it my junk box produces 800 VDC at 120VAC input. I'd like to run the output plates on the transmitter at 550VDC. The power supply output also has taps for the screens, receiver, and oscillator (which is regulated with a 200V 50W zener). This is a VERY stiff HV transformer and is rated at 1A output. I'm also using filtered 12.6VDC for the tube filaments as suggested. 

Thanks in advance for any ideas. 

73,

Mack de WB4MAK
www.nfarl.org
www.sedxc.org