Dreadbox Dysmetria - DIY Build
Known for their unique and limited edition synths, Dreadbox has done it again with their latest synth, the Dysmetria. A two part analog groove synthesizer, the Dysmetria has a lot going on in a small 42hp footprint. Since we just completed the Dreadbox Dysphonia, it only seemed natural to take the Dysmetria on right after for our second build of the fall season.
As described by Dreadbox, “Dysmetria uses a subtractive synthesis mode, where 2 VCO’s and a White Noise Generator are summed up into a 2-pole Filter (Low Pass or Band Pass). Then a simple VCA follows. Only 2 Decay envelopes are available, one for the Amp and one for the Filter or the VCOs. Also the powerful FM circuit, helps a lot with its percussive sound”.
Let’s get on with the build….
The Dysmetria kit is rather extensive and consists of a lot of components. You will want to utilize several tools for the build itself. Make sure you have a good iron and plenty of solder. A multimeter to help measure values will also come in very handy.
~ Quick Links ~
The Build ... Resistors and Diodes
Since there are so many resistors to place, it is ideal to measure their values prior to jumping into the build. By taking the few extra minutes to measure the components, build time is decreased by quite a bit. As you can see from the time lapse, we marked each set of resistors after measuring and placed them on both the voicing board and the control board accordingly. Remember that polarity does not matter with resistors, but putting them in the right place does. Take your time here.
Diodes are up next and unlike resistors, polarity does matter. You want to make sure to line up the mark on the diode with the mark on the PCBs. If you mess this part up, your synth will not function correctly. When you have placed all of the diodes, tack them down and move onto the crystal, 5v regulators and trimmers (located in bag 1.2).
The Crystal, Regulators and Trimmer pots
Next up is the crystal and it serves as the clock for the MCU. Polarity doesn’t matter with this part, but make sure you do not leave your iron on it for too long. It can fry the part and you would be S.O.L. Once complete, move onto the 5V regulators.
The 5V Regulators are fed with 12V and convert this to 5V. There are two of them, as you always want to have separate rails for the digital and the analog path. Take caution when placing and soldering these into place. You will want to be aware of your iron heat and how long you leave it on the component leg itself. Be quick and be thorough and then move onto the trimmer pots.
Last up are the trimmers and they will mount to the PCB according to the silkscreen. There is x1 100k trimmer and x5 1k trimmers that will need to be tacked down. After mounting, let the solder flow and move onto the next part of the build. You should have the following parts as leftovers from this step, 2x 2n3904 and the TL431. Put them to the side, as we will solder them later on.
Note: If you need to take a break, this is a good time to do so as we will be moving onto other major components and they require a steady hand and concentration.
Dreadbox Dysmetria - Time Lapse Build
IC sockets and Power Board
Next up are the IC sockets and their orientation does matter. Make sure the sockets are placed firmly on the board. You can start by soldering only 1 pin, flip the board to check and if they are ok, solder them down. If you are choosing to use the synth as a desktop module, you will want to put together the external power board. Since we are only using this synth as a module, we opted to leave this part of the build out.
Capacitors and Remaining Components
The capacitors are up next and there are quite a few of them. Start off by separating them out into piles according to their values as this will help with keeping track of all the parts. Ceramic caps can just be placed and tacked down without regard to polarity. Electrolytic caps have to be mounting according to polarity so make sure you pay attention to their orientation when placing them. (Note: When you come to the 47uf caps, only mount 1 of them). As for the box caps, polarity doesn’t matter with those either. Put them in their place and tack them down. Don’t forget to mount and solder the switch on the side of the PCB.
Remember the transistors leftover from the earlier step? Now it is time to place these and tack them down as well. You will want to pay special attention to their orientation and also remember not to keep your iron on the legs for too long. These parts can easily overheat and short the board. When you have completed this step, move onto the headers.
Flip the voice board over and mount the power header making sure to line it up with the PCB silkscreen. Then, you will mount the board header near the top of the PCB. The voice board will accept the 50pin male header and the control board will take the female later on. When you have completed the headers, the voice board is complete. Time to move onto the control board.
Dreadbox Dysmetria - Build Gallery
The Control Board - Jacks, Pots, Switches, etc
First up are the jacks. You can place these parts and then flip the control board over to solder them into their final destinations. After these, come the push buttons. When placing the push buttons (x2), keep in mind that polarity matters. To figure out their polarity, check their bottom side. The “+” sign should match the square pad on the PCB. Once you are sure regarding their orientation, push them firmly down to their position.
WARNING!: If the button is not pushed correctly, it will touch the aluminum panel and this will not allow it to rest to its OFF position – or it will not be able to be aligned correctly to the whole of the panel.
The next step is to solder the slider potentiometers. These can be tricky but we have found that if you place the pot and then carefully bend one of their legs on the backside of their mounting holes, it helps keep them in place when soldering everything down. The easiest thing to do is to just solder everything from the top down. Being that you just placed the 46 jacks, it can get tight when you solder from the top down. As mentioned previously, just tack one pin down and then flip the board over to finish.
Switches and Rotary Pots
Open the bag 3.4 and locate the 6 toggle switch and separate the ON/ON from the ON/OFF/ON. The ON/OFF/ON switches have a middle position, while the ON/ON have only two positions. Then solder these to the indicated place. Then add the two 10KB rotary pots and the rotary switch, located in the 3.2 bag.
Dreadbox Dysmetria - Audio Demo
Wrapping it all up…
First thing to assemble is the spacers on the control board. You will need the 10mm plastic ones (they have both sides threaded) and the 11mm ones (they have one threaded side and one with a “bolt”).
The 11mm spacers (the 1 side threaded ones) are placed on top, on the same side that components are. You will need to assemble 6 sets of these. Do not use any tool to tight the spacers. Do this with your fingers.
Next, place the ICs, making sure to match their orientation on the PCB. If you mess this up, the synth is toast and it will not function correctly. We used our leg bender tool to get the perfect 90 degree angle on the legs which makes the ICs easier to mount. Then, attach the 50pin female header on top of the male header and place a 15mm plastic header and M3 nut next to it in the open hole. Now connect the two PCBs, paying attention to alignment and orientation. Turn the module straight up to its feet, and solder the 50 pin header that is now visible and into place.
Panel Placement and Final Steps
Lastly, place the front panel on the control board and attach it using the small black bolts. Screw down the potentiometers nuts with your Synth DIY tool or your hand. Finally, place the knobs onto the pots using a small screwdriver and little force. You might have a few spare components laying around and that is to be expected. You just survived a very tedious build of the Dreadbox Dysmetria! Now it is time for calibration and tuning. Please refer to the guide provided by Dreadbox to complete these steps.
Dreadbox Dysmetria ... Our Final Thoughts
As for the assembly of the module, it is not recommended for novice builders. There are a lot of parts and it can easily be mixed up if you do not know what you are doing or how to read a BOM. Tuning and calibration are extensive, but worth it… take your time and go through all the steps.
With regard to the synth itself, we haven’t had a lot of time with the Dysmetria. We can say that it is nice addition to our rack and that we look forward to getting to know it more. Being that it is a limited edition synth, supplies are limited. As of this review/guide, there are still some of these available via the Dreadbox site. If you are looking to pick one up, do it fast as these are very limited runs and they will not be available once stock is depleted!
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 …