Analog Lab.Swiss Dual Sub101A - DIY Build
Here at fiN Studios, we are continuously looking for new and exciting modules, synths or pedals to build. Not only do we utilize them in our own racks, we enjoy helping promote other artists or instrument designers.
One of our most recent finds is the Analog-Lab.Swiss Sub 101A Duo which is a dual sub-oscillator eurorack module. There is even have a single version of the 101A if you only wanted one. We opted for the Dual Sub101A and have to admit, we are glad we did.
What is the Sub101A?
The Sub101A is a 6HP Eurorack Module who’s circuit adds a square wave sub-oscillator to your rack. In layman’s terms, it adds more bass or low end to the output of anything going into it. This is accomplished by tracking an oscillator signal from a VCO and then generating a square wave that is -1 or -2 octaves below that. Needless to say, it goes low!!
You can also mix between the 2 sub-octaves which can give the output a sound similar to the famous Roland SH-101 pulse.
Let’s get on with the build!!

Two PCBS … One Panel
If you opt for the dual version of the Sub101A, you will receive 2 PCBs and 1 reversible panel (this was pretty cool). Each PCB has its own individual components laid out with an easy to read placement guide. Carmelo, the owner of Analog-Lab.Swiss took great time in ensuring that his build would be easy for even the novice builders. He also supplied a build guide and some photos on his website and component sheet for reference. With regard to this build, we will only talk about building one of the PCBs as the dual Sub101A build just repeats itself minus a power header on one of the PCBs.
Resistors and Diodes
Starting with the resistors, follow the component guide to place these. You don’t have to worry about polarity with the resistors, but you do have to pay attention to this with the diodes. Make sure your diodes match the silk screen so that they do not short the module.
After placing all of the resistors and diodes, flip the board over and tack everything down (or use top down soldering like we did).
Dual Sub101A - Time Lapse Build
Caps, Electo-Caps and that lonely transistor…
The two ceramic capacitors can be mounted in any orientation but the electrolytic ones must match the silk screen on the PCB. Don’t forget that the long leg on the electro cap is the cathode and will be placed opposite of the white stripe on the board.
Note, there are only 2 electrolytic caps and 2 ceramic caps per board and C3 will remain unpopulated. Solder the pads together or use a resistor leg to bridge them. After the caps have been completed, mount the transistor ensuring that the flat side of the component is facing the appropriate way (towards the edge of the board).
Dual Sub101A Build Gallery
The Power Header, IC Sockets and Solder Bridges
One lonely power header will be mounted on the backside of the PCB. You will want to ensure that you are matching the silk screen so that the module doesn’t fry the first time you plug it in. If you are building the dual 101A, there will be only one power header to mount. The other PCB will have its power supplied by 2 wires connecting the two PCBs. (See photo of completed rear).
Moving onto the IC socket, pay special attention to the orientation of the header as it needs to face the appropriate way. When it has been tacked down, bridge pins 6 and 7 on the IC socket. (See photo of completed rear).
Completing the build…
Flip the board over and place the jacks, pot and LED… but do not solder anything yet. Make sure the short leg of the LED is placed in the – sign/pad on the PCB too. While doing this, tack down the ground pin on each of the jacks prior to placing the panel so they stay in place. Carefully set the panel on top of the jacks, pot and LED you just placed. Use one of the nuts from the pot or jacks to hold the panel in place as you flip the board over to solder everything down. (the same will be done on the other PCB if you have the dual version).
Wrapping it all up…
At this point, if you are building the single version of the 101A, you will be done with the module after placing the IC. If you are building the dual version, you will need to get power from one PCB to the other. This is completed by soldering a wire from the GND pad on one PCB to the other GND pad on the sister PCB. The same will be done with the VCC pad on each PCB. (See the photo above for reference)…
Take a break, pat yourself on the back because you have just completed the Analog Lab.Swiss Sub101A!
Dual Sub101A ... Our Final Thoughts
Overall, we are really pleased with the Analog-Lab.Swiss Sub101A Duo. The low end on the module really adds some “umph” to any thing patched through it. Think your oscillator has deep bass? You haven’t heard low ends until you patch it through the Sub101A. Aesthetically, the module is beautiful and the panel is reversible so you can choose how the module looks in your rack.
The build itself was quite simple but it did have some “gotcha’s” with regard to solder bridges and powering the second PCB. Make sure you keep the documentation handy and refer to it often if you get confused during the build process.
By any means, the Sub101A Duo is a solid module with a lot of future use in our racks. Head on over to ETSY and pick up one of these now… its price is right, the sound is heavy and the build is top notch.
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 …
