Motivation
I was in need for a simple precision adder for my quad system. Used for tuning four VCO. So I took my existing precision adder and removed not needed features to make room for the fourth adder. Two input voltages each are precisely added to the output. The accuracy depends on the used operational amplifier and the matching of the resistors. For pitch CV I recommend precision OpAmps like the LT1014 or similar.
Specs and features
- Eight inputs, four outputs. Each two inputs added precisely to one output.
- Runs on +/-12V and +/-15V
- Power consumption below 10mA each rail
Implementation
Schematic
Quad Precision Adder: Schematic control board
Quad Precision Adder: Schematic main board
Description:
...
Calibration
- None
Building hints
- Use precision OpAmps. Match resistors to 0,1% or better. Recommended 25ppm.
Special parts
- None
Download
Quad Precision Adder control board documentation downloadQuad Precision Adder control board Gerber files download
Quad Precision Adder main board documentation download
Quad Precision Adder main board Gerber files download
Quad Precision Adder front plate Gerber files download
Quad Precision Adder *.fpd file
Quad Precision Adder: Front view
Quad Precision Adder: Populated control PCB
Quad Precision Adder: Populated main PCB
Quad Precision Adder: Half front view
Quad Precision Adder: Half back view
