YuSynth Steiner VCF

Introduction

A bare double sided through hole plated PCB (no need for the wire jumper links shown on the PCB layout) 100x75mm for the Yusynth Steiner VCF synth module. 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 Steiner VCF project page for detailed information including Yves panel layouts but a summary is shown below.

Description

The PCB is designed to use either two matched BC547C (Q1-Q2) or a single 2SC1583 dual transistor.

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.
The module was designed to work with a +15V/0V/-15V PSU but can be used without modifications with a +12V/0V/-12V PSU.

Circuit

Click on the schematic thumbnail above for the circuit diagram.

Wiring

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

Setting and Trimming

Set both trimmers to mid-range position.
Adjusting CV rejection (trimmer T2)

1. Set the audio input potentiometer to 0.
2. Set the cut-off potentiometer to mid-range
3. Connect a square-wave signal (LFO or VCO) with a frequency of 50 Hz and a positive amplitude of 5V to CONTROL#1 input and set the CONTROL LEVEL#1 pot to maximum.
4. Connect the output to an amplifier or an oscilloscope, then you must hear some low frequency sound or view some modulation on the scope.
5. Adjust T2 in order to minimize the low frequency sound. If you cared to match the transistors and use matched resistors for R9 and R13, the minimum must be found close the mid-range position of T2.

Adjusting filter tracking (trimmer T1)

1. Plug a CV/GATE keyboard or a scaled source of voltage in the V/OCT jack.
2. Set the filter resonance in order to auto-oscillate.
3. Adjust the 2k trimmer in order to obtain a V/octave tracking (octave increment for 1V increment). Don't expect a good tracking over more than two and half octave.

Parts List

The parts list below is direct from the YuSynth website. Please note that Yves has identifed some components with a *, these component values can be changed to suit your own particular requirements / preferences. The value in the parts list is the default value and may differ to that quoted in the schematic / PCB silk image.

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.