I'm always shuffling though my parts pin to find the right power supply so I bought a mini buck converter unit to create a variable voltage power supply.
I connected this device to a 31.5 VDC laptop power supply and now I can adjust the output voltage to whatever I need.
Input Voltage: DC 5~40V
Output Voltage: 1.25V~37V (continuously adjustable, the input voltage must be 1V higher than the output voltage)
Output Current: 2A(normal and stable), 3A Max.
<$10, DROK Brand Voltage Switching Regulator at Amazon:
(Make sure to choose the option that has the LED display & heatsink!)