YuSynth Audio/CV Mixer

Introduction

A bare double sided PCB (no need for the wire jumper links shown on the PCB layout) for the YuSynth audio/cv mixer module that can be built up as a 1U or 2U version. The mixer is an utility module to combine signals or control voltages from various sources. Features of each version:

• one that fits in 1U panel with three inputs with adjustable level, a level LED, two outputs (one inverted);
• the second fits in 2U panel with four inputs with adjustable level, a general level control, a DC bias control, a level LED, two outputs (one inverted);

Both are based on the same PCB.

These PCBs are manufactured by Soundtronics with a percentage of the sale going to the creator of the YuSynth - Yves Usson. These are early days for the YuSynth Modular Synth at Soundtronics, our plan is to stock PCBs for all of the projects as well as components, kits and front panels. This is going to take time but will eventually be as comprehensive as our MFOS range.

No components are included with the PCB but check out our Synth Components section where you should find what you need. We do suggest visiting the YuSynth Mixer project page for detailed information including Yves panel layouts but a summary is shown below.

Erratum for Boards Shipped Prior to 17 August 2020

Sorry but there is two small errors on the PCB relating to the MOTM connector. Cut the track between the MOTM +15V pad and the 0V ground track and link the MOTM 0V pad and the ground track (you will need to scrape the solder resist from the 0V track.

1U Version Description

This module is a very useful utilty module in a modular synthesizer. It offers three inputs with adjustable level, a level LED and two outputs (one of which is inverted).
The schematics is really simple and is based on very basic circuits.
Works in +15V/-&(v as well as in +12V/-12V without change.

2U Version Description

This module is a very useful utilty module in a modular synthesizer. It offers four inputs with adjustable level, a general gain level potentiometer, a DC BIAS potentiometer, a level LED and two outputs (one of which is inverted). The schematics is really simple and is based on very basic circuits.
Works in +15V/-&(v as well as in +12V/-12V without change.

The PCB can accept a choice of three types of power connector, it can be either a Synthesizers.com 6 pins MTA connector, a MOTM 4 pins MTA96 connector or a 10-pin Eurorack connector.

1U Circuit

Click on the schematic thumbnail above for the circuit diagram.

This circuit is based on very basic building blocks. U1a is a summer inverter that sums up the input signals. The U2a acts as a simple inverter. D1, D2 and C4 act as a full-wave rectifier and controls Q1 which drives the LED

2U Circuit

Click on the schematic thumbnail above for the circuit diagram.

This circuit is based on very basic building blocks. U1a is a summer inverter that sums up the input signals. The U2a acts as a simple inverter. D1, D2 and C4 act as a full-wave rectifier and controls Q1 which drives the LED. P5 makes it possible to add a DC BIAS (from -5V to 5V) to the positive output only. D3 and D4 create a 0V dead zone in the middle of the run of the pot wiper.

Wiring

The wiring schematic image in the above thumbnails show the panel wiring to the pots and sockets etc.

Setting and Trimming

No setting up or trimming required

Parts List

The parts list below is direct from the YuSynth website.

The parts list excludes knobs although we have standardised on the Cliff KM20B but it does include 1/4" jack sockets. All parts are available individually (use the part number in the search box above) or as a components kit that excludes sockets and knobs.

1U Version

2U Version