Erica Synths Output - DIY Build

As the world of modular continues to grow, there is one module that is a must for any rack or system…. the output module. How else are you going to get your amazing performance to your speakers or interface to record? 

Erica Synths have been around a long time and their eurorack kits give DIY enthusiasts a chance to build their amazing modules. Their open source modules were previously discontinued and hard to come by until recently.

Packed and distributed by Synthrotek  the entire DIY line of modules is now available for you to take on! The Erica Synths Output module is a quick and easy build and is an essential module for any system. 

Before we jump right in...

Erica Synths Output - Completed Front

Since you are dealing with two PCBs on this build, we highly recommend reading the assembly guide when you are putting this module together. Things can get tricky because there are multiple things going on here.

Resistors and Diodes

As usual, the resistors and diodes are up first. Take note that some of the resistors are installed vertically on the main board and they have no specific orientation unlike the diodes. When placing the diodes, make sure they match the silk on the PCB. If you happen to get one of these switched up, you will spend some time either desoldering or just tossing the board away. Once everything is where it should be according to the BOM, tack everything down and move onto the caps. 

Caps, IC and more…

Next up you are going to place the IC socket and the ceramic caps. The ceramic caps do not have an orientation and they can be placed facing either way. Unlike ceramic caps, your electrolytic caps do have a specific orientation. 

The PCB silk shows you which way to install these. Just remember that the long leg on the cap is the positive (+) side and the shorty is the negative. This will help when you get to this point in the build. Place everything in its appropriate place and flip the board over to solder everything in place. (make sure you don’t miss the ones on the back of the controls board)

When installing the IC socket, leave the IC out. This will be the last thing you install prior to putting it all together. (this protects the chip from overheating as you solder). A handy way to place the socket is to take a dab of solder and fill one hole where the IC socket rests. Gently set the socket where it belongs and heat up the pad on the underside. If done correctly and with slight pressure, the socket will snap into place. You can then tidy everything up after you flip the board and let the solder flow. 

Erica Synths Output - Time Lapse Build

Play Video

Headers and fuses…

Before knocking out the controls board, make sure you have placed and soldered the pin headers on the sides of the main logic board as well. This helps mate the two boards (along with a standoff screw). 

Female pin headers and the power header are next (on the controls board). You can install these just like you did the IC socket by adding a small dab of solder into one of the through holes. Then by gently pushing on the component and heating the solder from the underside, the part will pop into place. Tack everything down when you are sure everything is where it belongs.

On the back side of the controls board, the resettable fuses also need to be tacked down. Once these are done, it is time to place the jacks and pots on the front side. 

Jacks, Pots and finishing touches..

With regard to the jacks, pay attention to the mono vs stereo jacks. Stereo jacks have a specific location due to their output. Mono jacks will go on the front of the control board where the silk reads “AUDIO IN L and AUDIO IN R”. The stereo jacks will be placed into the pads that read “HEADPHONES and AUDIO OUT”. Once these have all been placed, install the one pot for volume control. Place the panel of this completed board and then flip the board over to complete the soldering. The two boards are now ready to be put together for the final steps. 

Board Mating… (whoa.. sounds kinky!)

Carefully line up the main board to the control board and gently push them together. Once aligned, the set screw can be placed to keep the boards in their final resting place. When this has been completed, turn the module over, tighten down the jack nuts and install the singe knob that controls the volume. 

Now it is time to test the module and install it into your rack/system. We used our Synthrotek TST module to ensure that the module was good to go prior to installation. (we highly recommend having a couple of these TST modules btw). 

Erica Synths Output - Completed Module

Features and Specifications


  • L and R inputs
  • 3.5mm stereo output jack
  • 3.5mm headphones jack
  • Headphones volume adjustment
  • Skiff-friendly design
  • The module has L and R inputs, if you make stereo patches, but for mono patches R input is normalled to L input, so you automatically route the output to stereo mixer.


  • Visual BOM – Click Here
  • Assembly documentation – Click Here
  • Audio Output Amplitude: line level (optionally adjustable)
  • Width: 6HP
  • Depth: 35mm
  • Current draw:
    • +12V: 20mA
    • -12V: 7mA
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Erica Synths Output- Purchasing Options

Synthrotek offers a several options when it comes to purchasing the Erica Synths Output. Their prices are excellent and the quality of this build is way worth it! If you are interested in buying the kit, the assembled module or just the PCB/Panel/IC, click on the images below and you will be redirected to their site to purchase! Make sure and tell the gang at SR that we sent you!

Our Final Thoughts . . .

In the end… the Erica Synths Output module allows you to interface your modular synth with external gear (mixers or other synths with a 3.5mm stereo jack). Another feature that we really like is the high quality headphone preamp that we can use to monitor our masterpieces. Also, since it has L and R inputs, mono patches are normaled to the the L input so you can automatically route the output to a stereo mixer or mixer module. 

What else can one say about the Erica Synths Output module? Not a whole lot to be honest. It was an easy build but NOT recommended for beginners due to some of the components being really close together. You will want a steady hand when taking on this DIY kit. Lastly, sound quality is on point and the matte black finish on the module aesthetically looks great. At the end of the day, the Erica Synths Output module is a no brainer to have in your case!  

ps. A big thanks to Synthrotek for putting these open source kits together and making it possible for builders like ourselves to get a hold of them. 

Comments or Suggestions?

If you have questions about the build process or suggestions/feedback about this article, feel free to let us know by contacting us  We look forward to hearing from you!

Until the next build … 

~ f i N

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