I tested the minimum voltage to be applied on the kit to get a good regulation from the LM317 and LM337.
The regulators give an output voltage between +/-11.4V too +/-11.6V following tolerance of the resistors.
To obtain a good regulation and a minimum of noise, we must supply the kit with 2.5V higher than the output voltage.
Thus, the kit must be supply with (11.6V + 2.5V) 14.1V minimum.
It’s why I propose to use a minimum voltage of +/- 15V to supply the kit.
That will avoid some problems, like loss in the line, temperature problem, etc.
I do not think that the little "Universal +/-15V Power Supply" will help you.
There are already all components on the KIT.
You just need a transformer, 2 diodes and 2 capacitors of 1000uf/63V to build a symetrical power supply.
Like Dimitir say, on the PDF file I suggest some alternatives to build a fast, simple and not expensive power supply.