Error Instruments TOMO Eurorack Module - DIY Build

When it comes to unique modules in the Eurorack world, a few names come to mind. One being Error Instruments located in the Netherlands. The owner, Paul Tas is like a mad scientist when it comes to his creations and the new Error Instruments TOMO is no exception.

The TOMO is a new 12HP touch interface CV/gate controller for eurorack synthesizers. Originally released as a stand alone module, the “Ketchup” version of TOMO finds its way into DIYers hearts. We picked one up immediately after hearing of its release. 

So whats with the TOMO names?​

Ketchup, Toxic, Blanks, TOMO … these are all different names for the versions or panel colors of TOMOs. The Ketchup is the only DIY version and basically matches the color of our favorite dipping sauce. This is the kit we assembled for this review and build video. TOMO Toxic is a yellowish green color and TOMO blanks is a white version of the glitchy touch controller. 

The original TOMO panel comes in a black and is still readily available if you are interested. They are all available over at Pauls ETSY shop.

Enough with all the filler, let’s get onto the build!

TOMO Time Lapse Build Vid

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Upon receiving the module from Error Instruments, we quickly fired up our soldering iron and laid everything out. To our surprise though, there wasn’t a lot to “lay out” in the kit. It was very simple and the panel was the PCB as well. A few capacitors, an LED, some jacks, some wire, a potentiometer and an IC pretty much made up the kit. We jumped right in and pre-soldered the pads with a little solder to ready them for components.

When mounting the caps, you want to make sure to take note about how they are being soldered to the panel/PCB. You have to cut most the leg off and bend the ends outward to meet the pad.  A quick heat up of the pre-solder and some careful hands and we had the caps all mounted. These will look like they are being mounted at an angle since the panel is the PCB.  With that being said, just make sure you get the polarity correct when placing them on the board. 

Putting your soldering skills to a test …

Once the capacitors were done, we moved onto the IC and the power header. These mount through the panel and are soldered on the face of the panel. This is where your soldering skills will be noticed as these are front facing. A little flux and some solder and we were good to go. Moving onto the jacks, you will want put these on the panel via the thumbscrew.

After being mounted, you want to take the extra wire and connect one leg of the jack to the panel. The jacks are ultimately grounded via the pcb so there is no more soldering that needs to be done with them. 

TOMO (Ketchup) Build Gallery

The jacks on the TOMO are self explanatory. There is one input, one output and one CV out which can be routed to almost anything in your rack that takes CV input. With the CV out function, you can control the parameters of other modules. With a buffered multiple per example, you can multiply the signal and then play several parameters with the touch interface. You can patch the input of an audio source into the TOMO and get some very interesting sounds based upon the incoming audio and how hard/much you press the TOMO’s interface.  

What about that single pot?

After the jacks were completed, we moved on to the LED and the main potentiometer. The large yellow LED gives the Error Instruments TOMO (Ketchup) model its unique flair. It is joined by the single pot that controls how much glitch comes through the module. Error Interments supplied the kit with a slip on pot cover and we quickly pitched that for a real knob. We used a retro style one to help keep the look of the TOMO.

When soldering the back of the pot, take note that it doesn’t line up completely with the pads on the panel/PCB. You have to bend the ends of the pot to mount it flush to the panel which leaves the ends pointing off to the corner of the pads (this happened on two of ours). Some tweezers quickly solved this and therefore we were on our way. A little bit of extra solder to help bridge the gap on one of the ends and the pot was ready to go.

Flux was used throughout the build to help keep our solder joints looking good and this is highly recommended if you plan on building the Error Instruments TOMO (Ketchup). When we were all done with the build, the final step was to clean off the panel/PCB and fire it up. Our good old friend 90% isopropyl alcohol and a toothbrush came to our aid. 

In our audio sample video, you can see the TOMO being the root of all of this chaos. Details of our patches are in the audio sample video itself so you can see what and how we patched it during our short amount of time with it. 

Completed Rear Panel
Completed Rear Panel

TOMO Audio Patching Examples

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Our Final Thoughts . . .

In the end, the Error Instruments TOMO (Ketchup) is a versatile touch controller. With its CV out and ability to expand into other things via alligator clip touch points, the TOMO quickly became a favorite of ours. Building the TOMO was exceptionally easy, partially due to its simplicity. It is a quick build for beginners and its simple interface makes for glitchy goodness when patched correctly … or incorrectly. Hence, that is the beauty of the TOMO… there is no correct or predictable way of using it.

UPDATE: We actually have another one headed our way (TOMO Toxic) and look forward to picking up many more of Error Instruments modules!

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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