Four-channel drum synthesizer desktop module
Within a year since the first teasers emerged, The Division Department, a collaboration between two synth nerds (in the most positive sense), delivered their four-part drum synthesizer 01/IV. Chance had it that I just swapped a modded RD8 for an 01/IV, so I thought I’d post a couple of impressions and sound examples. This is more a teardown/decsription of technical aspects than a modding project, although there is some good potential for additional I/Os outlined at the end.
As for a general descripion and manual, check their company website, and have a look at this thread here too, where Covariance, one of the people behind the project, gives some hints as regards their design choices for the 01/IV.
Playing around with the 01/IV
Somehow I first thought of the 01/IV as my next best option to a second-hand Ultimate Percussion K2-X, which always seems to elude me (and is still on my radar because I’m a sucker for Plaid), but I happily stopped comparing after the first minutes with the 01/IV. It’s super fun to play with this thing, and you can easily lose yourself pushing and twiddling. Midi control is also very flexible since you have a variety of options to play triggers, retriggers, chromatically and/or several drum channels at once, and some LFOs and Hex Noise paramaters can be tuned per midi CCs. Although I’ve not not yet bombarded it with data, there were no timing issues or double/non-triggers so far via midi or otherwise.
Each voice follows a classic substractive synthesis pattern, in which a source sound (Tri, Saw, White Noise, Metal Noise) passes through a non-resonant 12db filter (LP, BP, and HP) and final VCA. There are two decay envelopes and an LFO/SH-circuit per voice, and using these can give you fat kicks, zaps, hats and all sorts of electronic sounds.
The overall sound character is clean, precise and has, as Schneider’s put it, “grip”. the exponential character of the envelopes is immediately noticeable and so is that sounds are consistent when triggered several times. This is great for recording sounds dependent on first transients (i.e. kicks) because it reduces the necessity of editing.
If you play the four instrument as separate voices, you can quickly create instantaneous band-in-a-box arrangements or rotating synth figures à la Vermona Perfoumer (although with a different sonic character).
Yet things get really funky when you enage some of the extremely clever modulation options. Besides the Envs and LFO, there are different forms of note repeat that go from slow up into the audio rate, a ramp modulator with different shapes, and you can turn each voice into a drone synth, where pressing the trigger button once starts and pressing it a second time stops the drone (per midi you can have this gated, i.e. as long as you hold the note). Finally, two pairs of voices (1 and 2, 3 and 4) can frequency-modulate each other in different ways, which can result in super lively patterns.
Apart from a great sound that covers a lot (except maybe full-on snares), the 01/IV offers one of the most flexible hands-on modulation options available outside Eurorack turf, which is why it won’t be leaving me soon. In terms of its sonic characteristics, its looks, feel, and possible complexity of sound design, this box is just amazing!
Some gripes but no dealbreaker
All in all, The Division Department delivered a really great box and deserve to do well with the 01/IV, yet some very few things could and one definitely should be addressed.
First of all, the VCO tracking is less than ideal. Testing channels 3 and 4 at even pitch without any modulation, I found them drifting badly apart over the course of one single octave. Yes, this is a drum synth ladida, but my Pharmasonic can do it over a couple of octaves and many other drum synth can too, so I’d really love to see this improved via firmware or information by The Division Department if one of the trimmers inside the unit is for VCO tracking calibration.
Rather a case of RTFM than anything else is that note repeat settings can result in non-WYSIWYG cases, i.e. some sound parameters not corresponding to knob/switch position. For instance, when drone mode is activated via repeat knobs and you change the switch back to a different mode, drone is still active. This is good, since you can activate drone and then start sculpting your sound further, yet it requires you to remember what you did there in your last session. Another thing I’m not sure of is related to chromatic play and trigger – in one setting I dialled in a sound using the trigger button and then played it chromatically via a keyboard, which then also transposed the pitch of the trigger button. I’d wish that the pitch of the note played via the trigger button remains in lock with your pitch pot at all times, because then you just know what’s what by looking at your pitch pot. All in all, however, these setting aspects are possibly just related to preferences, I’m happy to get used to them.
Teardown and rudimentary technical description
Chassis construction and performance controls
The metal chassis is sturdy and beautifully designed. All connections on the back are wobble-free and (ecxept for the power switch) flush. The whole thing stands even on its four rubber feet.
The control layout is very clear an logically organized with all four channels having an identical set of switches and pots. The potentiometers run smooth and just easy enough. Mostly the scaling of parameters is exactly right and the range well-chosen.
I’m not a live performer, so my input as regards gigging with the 01/IV will be limited, yet what I noticed is that you can easily change pitch accidentally when flicking the switch above. The non-velocity sensitive trigger buttons for each instrument are a joy to play, really! They are placed on a spring, have very light action, and although there is some sideways movement, you cannot manage to get them stuck or produce glitchy double/non-triggers.
Disassembling the 01/IV is easy. Remove the four bottom screws, then remove the 64 pot caps and nuts, remove the 8 copper spacer screws on the bottom of the PCB, then flip the unit so that the top chassis is facing up and lift the latter gently.
Both chassis and the single PCB are excellently engineered and protected. A total of 12 spacers connect the PCB with the chassis and all pots are PCB mount, panel mount, and protected against dust and dirt with thick plastic washers. The trigger switches are sealed, and the PCB itself is sturdy.
The PCB layout itself is very structured and all parts are clearly labelled. There are three power rails (-9V, +9V and +5V) and a plethora of testpoins (three per voice, and then some) and trimmers (a total of 16, so let’s hope that four of them are for VCO tracking). The individual voice outputs are switched jacks, with each plugged jack subtracting the respective voice from the main mix. There are two microprocessors, which, I assume, are for handling midi and modulation duties (note retrigger, LFO/S&H, and ramp).
As mentioned, each of the four voices have identical features, which is also reflected in the parts used. VCO, VCF, VCA and envelopes are analogue, while the LFO/S&Hs apear to be digital (need to verify the latter).
Per voice you have two 4069UB CMOS hexinverters (for VCO and filter), one TL064 op-amp, three TL072 op-amps, 14 matched transitor pairs, 6 single transistors, and a bunch of passive components. The VCO revolves around a 4069UB CMOS, and so does the 2-pole state-variable VCF, while the VCA and the envelopes are built around op-amps. As regards design, these sections are clearly transferred from the Pearl Syncussion, with the difference of the latter sporting two VCOs per voice but no state-variable filter. While the white noise is based on TR909-style filtered digital noise, the metal noise is of the TR808 kind, consisting of six square waves (tunable per midi). In terms of sonic choices, I find this circuits excellently curated and bound to keep your ears happy for years.
Potential for (DIY) extension boxes
What would be most interesting to me in the future would be an extension panel/box with lots of I/O for modular use. Hopefully The Division Department will come to the rescue and offer something. In the meantime, here are some preliminary points on potential DIY connections. What could be achieved easily :
- VCO direct outputs: you can tap the VCO selector switches directly via their pins at the back of the PCB. The pins don’t carry Tri and Saw simultaneously, but white noise and metal noise are available at all times.
- VCF outputs can be had via the filter mode switch pins (separate LP, BP and HP outputs are present there simultaneously)
- Modulation CV inputs for VCO pitch, VCF cutoff and VCA level can be addressed separately via the modulation switch. I did not measure voltages, but the acceptable range seems to be between +/-2-3V
- I did not check with a cope yet, but LFO/S&H should be available for outputs, so should be the outputs of the two decay envelopes (via the pins of the RANGE and FILTER pots) – this needs verification though
- Equally up for verification are the testpoints per voice.
Analogue triggers speculation (clickbait much?)
When asked whether triggers were planned, Covariance stated on GS that there were plans for a Tigger-to-Midi Eurorack module, which is also linked on their website by now. Fair enough, yet direct triggers might be desirable for some, and it’s interesting to see that there is an upopulated place for a resistor besides each trigger button on the 01/IV. On the trig button picture above you see R1D unpopulated (so R1A through D are free). Didn’t dare testing yet though, and the fact that the resistors are not populated does not need to mean anything as it is not uncommon to plan for components and then decide last minute against them (have a look at the PCB of the TD3 by Behringer, for instance, where you can find many such changes).