Had a spare 3d printer 260 watt 12v psu and with a simple modification i converted it to a variable psu range 4.8v to 19v ..

follow the guide here
http://imajeenyus.com/electronics/20151028_smps_variable_voltage/index.shtml

then i designed the case for it to incorporate the variable pot, led display and two bannana plugs

Parts

IEC plug push fit
rocker switch
led display 0.56" - 0 30v
2 x banna plugs
1 knob

Electronics

2k2 resistor
2k resistor
10k variable linear pot
47nf capacitor