My old PSR220 requires a PA-3/3B but I'm using one of those Radio Shack switchable voltage PSUs that puts out 800mA. I did some voltage measurments on it and found the following: set to 12V the off load voltage was 16V, at 250mA the output voltage was 13.5 V and at 800mA the voltage was 10V. Set to 9V the corresponding voltages were 12.2, 10.5 and 7.5. Not what you would call regulated. It works OK with the PSR at the 12V setting because the output chip can take 25V and the rest of the circuitry has regulators which can take care of the overvoltage. I wouldn't be surprised if the the QY has similar hardware.

Bryan