MRG ADSR Assembly Guide

The MRG 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.

adsr pcb

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

adsr pcb

Step A2. Solder all ceramic capacitors.

adsr pcb

Step A3. Solder the linear voltage regulators, electrolytic capacitors and the vertical 1N4001 diodes. Note: on both diodes, the grey line (cathode) is up!

adsr pcb

Step A4. Solder the 10-pin header Eurorack connector.

adsr pcb

Step A5. Solder the timing capacitor.

adsr pcb

Step A6. 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.

adsr pcb

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

adsr pcb

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

adsr pcb

Please Note: There are two types of potentiometers required. One A100K and three B5K. B5K goes in slots U2, U3 and U5. A100K goes in slot U4 (see picture below).

adsr pcb

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.

adsr pcb

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.

adsr pcb

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.

adsr pcb


Feedback? Suggestions? Contact me!.

Bill of Materials

This is the complete list of components needed to build the module if you buy panel + PCB + IC only.

Note: Use of 1% tolerance resistors highly recommended.

ComponentQuantityPackage

ICs:

TL072BCP2

Resistors:

4701
1K3
10K4
30K1

Ceramic Capacitors:

3.3nF1
10nF1
100nF7
220nF2

Other Capacitors:

39nF PP Film Capacitor15mm pitch
22uF Electrolythic Capacitor2

Other Components:

78L051
79L051
1N40012
1N41486
14 Pin 2 Row Header2
14 Pin 2 Row Socket2
10 Pin 2 Row Header1
A100K1Alpha 9mm Pot
B5KK3Alpha 9mm Pot
PJ398SM 3.5mm Jacks4