Here’s a type of powersupply you should have. It’s good if you’re dealing with OP amps. I took the circuit from eleccircuit.com and modified it to incorporate 2x printer power supplies instead of an AC transformer. It provides a ground that are both positive and negative. LM317 and LM337 regulators are utilized in this circuit. They are the main components of the circuit. It uses 2 diodes and a 2.2k 2W resistor for each regulator’s adjustment to 0v. It has 3 diodes for each regulator to be used as its protection diodes like capacitors and short circuits. The two 5K potiometers adjust the output voltage at each output. Printer power supplies are perfect for this project since their voltages are not too high or low.
The project is built on a dick Tracy lunch box. With the printer power supplies inside with a c7 power cord splitter. It uses LM317 and LM337 to provide both positive and negative voltages. Here’s a joke: So I guess that means the LM317 and the LM337 are like the yin and yang of electronics!