Mini Mixer

This is a Four Channel, Mono Output Mini Mixer. A great tool to have in your home studio or on your pedal board for parallel effect chains. This is a fairly simple kit to build. Follow the Bill of Materials, the Layout Diagram and General Build Instructions. 1 – Mount the potentiometers, knobs, LED and jacks onto the enclosure as shown above. 2 – Populate the resistors onto the PCB. Special note about resistor R10: R10 value controls how much gain the mixer will give. The lower the resistor value the higher the gain/volume you can get from the mixer. We have found that higher gains produce more white noise from the output. We settled on an 82k resistor for the kits since this give about unity gain and keeps the background noise down.

3 – Populate the capacitors and the IC socket onto the PCB. It's good to bend the tall electrolytic capacitors down flat as in the photo below so that the PCB has a low profile.

4 – Solder the wires into the pads on the PCB. Insert the IC into the socket.

5 – Wire the circuit together as shown in wiring diagram (and the photo below). Here's an inside view of the unit we built to give you some general ideas if needed.

Here is a chart of voltages taken at the IC pins. Use these voltages as a guideline. You may not get the exact readings listed, but should be somewhere in the area.

Component

Location

9 volt power supply

Voltage

9v

IC1

Pin 1

4.5v

IC1

Pin 2

4.5v

IC1

Pin 3

4.5v

IC1

Pin 4

0v

IC1

Pin 5

4.5v

IC1

Pin 6

4.5v

IC1

Pin 7

4.5v

IC1

Pin 8

9v