I purchased an accuphase clone 3850 preamp kit based off of Micheal Beany's YouTube video. It requires a 15 0 15 power supply and has 7815 and 7915 regulators on it. Until I get a transformer with the right secondaries can I test it using 2 DC power supplies? I have 2 24v 1amp wall warts that are isolated, can I wire these to the power input before the bridge rectifier or should I solder directly to the input pin of the regulator?
If your wall warts are DC I'd wire them between centre-tap (0V) and the AC inputs to the bridge. The wall warts would need to be joined +ve to -ve (i.e. in series) and that junction connects to the CT (centre tap) of the AC input.