This module is part of my Eurorack series. It is a simple mixer with four channels. There is an inverted output signal in addition to the not inverted one.
Buy kit or PCBs in my storeKey features#
- four channel mixer
- for audio and CV
- additional inverted output
- easy to build, all through hole components
- 6HP
How it works#
The four channels are summed up and can be attenuated individually. In addition to the normal output there is an inverted one. This makes it not only great as an output section for your modular but can also be used to mix control voltages.
Assembly#
The build is pretty straight forward. The module only consists of through-hole components and is easy to assemble. There are three boards: a front panel, a board for controls/jacks and a board for the circuit.
First, solder all parts on the component board. Keep the jacks and potentiometers for the end. Begin with the components with the lowest profile and work your way up. Screw the jacks and potentiometer to the front panel before soldering them. All components have a fixed designator and a component value printed on the board. Additional information on the parts can be found in the BOM below.
See the Component Basics guide for help identifying parts.
BOM#
Link to interactive BOM of the component board
| Reference | Value | Footprint | Description | Qty |
|---|---|---|---|---|
| C1, C2 | 10u | Capacitor_THT:CP_Radial_D5.0mm_P2.50mm | electrolytic | 2 |
| C3 | 100n | Capacitor_THT:C_Disc_D3.0mm_W2.0mm_P2.50mm | ceramic | 1 |
| J7 | EXT | Connector_Molex:Molex_KK-254_AE-6410-02A_1x02_P2.54mm_Vertical | additional inputs, optional | 1 |
| J8 | CONN | Connector_PinSocket_2.54mm:PinSocket_1x05_P2.54mm_Vertical | 5-pin socket 2.54mm | 1 |
| POWER1 | Conn_02x05_Odd_Even | Connector_IDC:IDC-Header_2x05_P2.54mm_Vertical | IDC 10-pin | 1 |
| R1, R2 | 10 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | 1/4W 1% resistor | 2 |
| R3-R5 | 100k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | 1/4W 1% resistor | 3 |
| R10, R11 | 1k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | 1/4W 1% resistor | 2 |
| U1 | TL072 | Package_DIP:DIP-8_W7.62mm_Socket_LongPads | 1 |
Link to interactive BOM of the control board
| Reference | Value | Footprint | Description | Qty |
|---|---|---|---|---|
| J1 | IN1 | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | Thonkiconn 3.5mm jack sockets | 1 |
| J2 | IN2 | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | Thonkiconn 3.5mm jack sockets | 1 |
| J3 | IN3 | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | Thonkiconn 3.5mm jack sockets | 1 |
| J4 | IN4 | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | Thonkiconn 3.5mm jack sockets | 1 |
| J5 | OUT_NEG | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | Thonkiconn 3.5mm jack sockets | 1 |
| J6 | OUT | Connector_Audio:Jack_3.5mm_QingPu_WQP-PJ398SM_Vertical_CircularHoles | Thonkiconn 3.5mm jack sockets | 1 |
| J7 | CONN | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | 5-pin header 2.54mm | 1 |
| R1-R4 | 100k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P10.16mm_Horizontal | 1/4W 1% resistor | 4 |
| RV1-RV4 | 100k | Potentiometer_THT:Potentiometer_Alpha_RD901F-40-00D_Single_Vertical | linear, vertical, threaded, 6mm | 4 |
Schematics#
