I am building a +/- 45V power supply to drive a master-slave amplifier for a sonoluminescence experiment. I am following a stock design, and am having massive sag problems. The circuit powers up fine, but if I engage the LED indicators (each draws about 0.015 A), the supply starts to sag, and the voltage drops to around 10 V. Hooking up a power resistor is much worse - 75R 100W should draw 0.6 A, but the voltage plummets to less than 1 V almost immediately. I tried disconnecting the Varistor network, but that didn't fix the problem. The bridge is rated at 6A 600V, so that shouldn't be the problem. Diodes D1 and D2 are 5 1N4001 diodes in parallel, to allow more current (and because I had them laying around).
I am using the schematic shown below, based off of standard circuits in the data sheet for the LM317HV and the LM337HV (HV = high voltage versions, these can handle +/- 45 V), and Rod Elliott's Bench supply, found at: https://sound-au.com/project44.htm.
So here's what I'm using:
I plan on adding protection diodes to the output, to prevent external voltages from feeding back into circuit, but I haven't done so yet.
I would be happy to answer any questions or perform voltage/current tests to try and track down the problem.