MRG 3310 ADSR Assembly Guide

The MRG 3310 ADSR module is completely through hole. Its build should be considered of medium difficulty given the number of components and steps required.

If you need help, you’ve spotted an error, or just need clarification during this process feel free to contact me . I’ll be happy to help.

Theory of operation:

  1. If you bought the PCB+Panel+IC only, acquire needed components (See Bill of Materials ). All components used in this guide are already included in the full DIY kit.
  2. Build the Main PCB .
  3. Build the Front PCB .
  4. Final module assembly .

Main PCB Build

The suggested order is to start soldering resistors and DO-35 diodes first, and then the rest of the components. The last components to be soldered should be the pin headers.

Step A1. Start by soldering all the horizontal resistors and the 1N4148 diodes.

Step A2. Solder all ceramic capacitors.

Step A3. Solder the linear voltage regulator. Check that each component is laid out as in the picture below:

Step A4. Solder the electrolytic capacitors and the vertical 1N4001 diodes. Check that the diodes are laid out as in the picture below:

Step A5. Solder the timing capacitor.

Step A6. Solder the 10-pin header Eurorack connector.

Step A7. Solder the two TL072 ICs and the AS3310 IC. If desired, you can solder IC sockets at this stage (two 8-pin and one 16-pin), and insert the ICs in the sockets later on.

Everything apart from the two 14-pin headers are soldered on the board now. It is time to solder the front PCB.

Front PCB Build

Step C1. Check the alignment of the PCB (label U1 is the top row), arrange the jack sockets and the potentiometers.

Step C2. Solder the components. Tip: in order to be sure to align the components to the front panel, install the front panel as in photo below and solder the components on the back.

Step C3. Solder the socket headers. Tip: In order to align the Main PCB’s pin headers to the Front PCB’s socket headers, assemble the two PCBs together, as in picture, and solder them in place.

Congratulations! The build is nearly done. All that’s left is installing the front panel.

Final Module Assembly

All that’s left now is to install the front panel, using nuts and washers to keep it attached, and adding the knobs to the potentiometers.

Feedback? Suggestions? Contact me! .