Circuit Benders UK drumBs - DIY Build
This months modular build comes from CircuitBenders UK. drumBs is a eurorack or stand alone module that we happened to come across while surfing ETSY. Being that there were no full kits available, we opted for a red panel, and 2 PCBs (one logic board and one control board).
Since we are currently working on building a drum rack with multiple modules, drumBs seemed like a natural choice for our system. drumBs is a tweaked version of the Syntom II, an analogue percussion project first published nearly four decades ago in the April 1983 edition of the mighty Electronics & Music Maker Magazine.
According to the ETSY listing and the CircuitBenders UK website, drumBs can “create a wide range of basic analogue percussive sounds and the synth features both a VCO and a noise source, along with a resonant noise filter and an auto roll function. It requires a +5V trigger source to drive the module”. Let’s get on with the build shall we?
The Build (Logic Board and Control Board)
All of the components in this build were outsourced via Mouser, Modular Addict and Tayda electronics. We happened to have a lot of the parts left over from previous builds but it is always a good idea to circle back and double check your BOM to ensure that you have everything you need (including the right values) prior to jumping into the build.
We started the build with the 3x diodes and the resistors. With diodes, just make sure they match the PCB and are sitting at the correct orientation or you will get nothing from the module itself. As for resistors, you can place these in any orientation you choose as their polarity doesn’t matter (like diodes).
IC sockets (Logic Board and Control Board)
Next up are the IC sockets. There are a lot of them so make sure you have the correct socket for the proper build section. There is even one on the control board that you need to be aware of. You can place a dab of solder on one pad and then heat it up and click in the IC socket from the opposite side as you heat the solder dab. Use this same method with the power header ensuring that you trim down the left over solder blobs from the opposite side of the PCB before placing the shrouded power header or 2×5 pin (whichever you chose).
After the resistors, diodes, power header and IC sockets, we turn our focus to capacitors. Electrolytic require a correct orientation whereas film and ceramic do not. Place these accordingly on the front of the logic board and flip the PCB over to mount the electrolytic. The gang over at CircuitBenders were kind enough to mark where the electrolytic caps go on the back of the logic board due to the sizing of the panels and PCBs. (thank you!).
Circuit Benders UK drumBs - Time Lapse Build
Noise adjuster trimmer and the BC108B (Logic Board)
The noise adjust trimmer pot should be mounted on the rear of the board so it can be adjusted when the module is put together. As for the BC108B, this tiny little metal can is mounted on the front of the control PCB and needs to match the orientation of the silkscreen on the PCB prior to soldering.
Stand Offs and Pin Headers (Logic and Control Board)
Next line up the pin headers, both the male and female counterparts and gently place them into position between the PCBs. You will use the 11mm stand offs on the corner of the PCB to hold everything into place as you tack the pin headers into place. Once this has been completed, you can move onto the control board.
Transistor, resistors, LED, jacks and pots (Control Board)
Last up is the control board. Start by referring to the BOM and place the resistors if you skipped this section earlier in the build. There are only 3 of them so it goes relatively fast. When this is complete, place the LED (do not solder) and then solder the transistor into place.
Next up, place the pots and jacks in their relative positions according to the BOM and set the panel on top of the control board. Hand tighten nuts onto the pots and flip the boards over to solder everything into its final resting place. When you have completed this step, it is now time to disassemble everything and set the IC chips on both the logic board and the one on the control board.
Take your time and make sure to bend the legs at a 90 degree angle to ensure their placement. You want to also to be sure to line things up with the PCB. There is often a little notch at the end of the socket and one also on the chip itself…. (no brainer here).
Knobs (Control Board)
After completing the IC chip placement, it is time to reassemble the module with the stand offs and the screws/nuts for the pots. Upon completing this, locate your knobs and start by setting them onto the module as needed. You can use whatever type or color you would like. We used white Davies 1900H clones on our red panel and believe it turned out looking kinda badass. You may now take a break and pat yourself on the back…. you just completed the drumBs by CircuitBenders UK.
drumBs - Build Gallery
Circuit Benders drumBs - Final Thoughts...
Upon completing the build, we knew it was time to calibrate the module and see what we could get it to do. We had watched several videos on the module and in these videos, the bass drums were kicking (you can find them on the CB UK main site). Ours on the other hand, didn’t do this. We did get some hi-hats out of our module as well as some really wild and rad circuit bent sounds in the short time we spent with the module, which kinda just made us smile. With outsourced parts you never really know what you are going to get or what type of sound you might come across based upon the component.
As for the build, it was a semi-easy one that took a couple hours to complete. We highly recommend this module due to the easy of the build as well as for what it can do. At the time of this build, we have already ordered another drumBs in blue color just to add another to the system with the hopes that we might encounter that deep bass sound that we are longing for. Cheers to the drumBs and Circuit Benders UK.
ps. Tell them we sent you if you decide to order up one of these cool little drum 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 …
