These are many pre tone control circuit, use transistors as main. so low noise,good sound, cheap and easy to buy parts, you can builds with PCB layouts
Cheap adjustable 0-30V 3A Laboratory DC Power Supply. high efficiency regulator circuit by IC regulator UA723-TIP3055 as power.Protect over load maximum 3A
If you need a dual power supply. But you only have a single supply source. So should build this power supply splitter circuit.
Simple DC to DC converter using 555 timer IC. You can build easily it.