Hello Victor dear, Noel, consider the formula of power voltage x current = power
If 3 amps are going to circulate through the output transistor and they will remain at 37 - 15 volts = 22 volts
22 volts by 3 amps are 66 watts, the transistor heatsink will have to be huge, imagine what heats a 60-watt incandescent bulb or a 60-watt soldering iron how are you going to get that temperature?
buy a chord transformer or take turns of the secondary you have;)
victor goes my like;)