Starting off a new bad habit

I purchased a Make Noise 0-Coast last week (my fourth monosynth), and it pretty much immediately made me start to feel the itch for a full-on modular. My prior experience with modular-style programming was when I previously owned a Nord Modular many years ago.

I'm planning on using an Arturia RackBrute 6U as my case, and at least for the short to mid-term would like to keep everything contained within that case. I have this rack designed with two approaches in mind:

The first approach is to be played as a cohesive whole with a MIDI keyboard or sequenced from my computer with a single set of CV/Gate, creating complex layered sounds and sounds not otherwise possible on my existing synths. Pretty much this would be the "super monosynth" among my other monosynths (a Bass Station 2, a Minitaur and the 0-Coast. I will be selling my MS-20 Mini to make space for this system).

The second approach is to be able to break it down into 3 or 4 small voices and control those voices with my DAW (Reaper). I already have a Korg SQ-1 as a MIDI to CV converter (bought it with the MS-20 Mini) and also have the 0-Coast available to do conversion as well, and include the Doepfer MIDI/CV interface in this rack to get access to a fourth set of CV/Gate. I'm not going into this with the notion of it being a "polysynth", but rather four independent voices that all sound different and work together.

So I wanted to run this design by people with more experience than I to see if there were any glaring design errors in my proposed setup, or see if anybody had any suggestions on possible improvements to this setup.

Thank You.

It kind of strikes me that if the intent is to avoid duplicating the sound of the other synths, you might want to reconsider that SE 4075 filter. While the Binary Filter does have some non-typical weirdnesses, the 4075 is sort of a rev.3 ARP 2600 filter minus the high-end dullness. Having used a rev.2 for a long time (basically, what the rev.3 was intended to replace after the Moog lawsuit; the sound is similar, but with the high-end mod done to the rev.3, it's very similar to the original 4015 (rev.1 and 2) which I'm familiar with) the sound is...well, it's that old-school LP ladder sound. However, there's ways to get that and a lot more with some other modules, which could give you a lot more timbral options. Or you could rely on the Binary as the 'typical' filter and go off in some stranger directions to replace the 4075; adding something that does CVed formant filtering, for example, gets you into the general zone of things like the Synton Syrinx, a very nifty and rare device.

Don't think that 'basic' is bad...it's actually quite good unless you already have 'basic' on hand and you're trying to push a sonic envelope with the modular...which would be the right move, as modular is often about pushing the envelope. Now, one thing that could be done to get at that might be to drop the Levels and instead swap in...wait for it...FIVE 2hp mixers. WTF?, you say? OK...look at the DixieII+s for a sec. Each of these has multiple simultaneous waveforms, plus a suboctave out. By putting a 2hp 4-in mixer with each, you then get the ability to waveshape by mixing waveforms, resulting in a much greater variety of timbres even before filtering. And you still have two more left, which could be dropped in most anywhere for either audio or CV duty, since they're DC-coupled.

And speaking of DC...which sucks if you output it from your final outs...you might look at an isolating output. Happy Nerding has this 4 hp thing, the Isolator, which offers balanced stereo outs (TRS 1/4") with transformer isolation and a ganged stereo level control. You'd lose the headphone amp, but given that you pick up ground-loop killswitching plus the nice transformer sound, that'd actually be a plus. It's cheaper, also.

Maybe also drop the mults...the space you're in is a little tight for those to be onboard, plus you don't have enough voltage splitting to warrant buffered mults. Instead, reclaim a little more space and use inline mults or stackable cables like Tiptop's.

As for the MIDI interface that's there (an Intellijel uMIDI), it actually does more than this system needs, such as clocking for a sequencer, which you don't have one of in the build. If you're considering using external conversion with the SQ-1 and/or 0-Coast, may as well boot that out too. Just those two devices alone give you two channels of CV/gate, which is plenty; going for four separate signal flows in this small a space is probably a bit of a stretch.

Last thing I'd do here would be to change up the layout a bit. Try and get your audio chain in one row, the control chain in the other. I can pretty much guarantee it'll make the synth easier to use in the long-term.

Thus far, though, the idea's on the right general track. Now try and see if you can mash things even tighter while at the same time reducing the monetary outlay. I think you'll be able to pull that off pretty easy-like!

It kind of strikes me that if the intent is to avoid duplicating the sound of the other synths, you might want to reconsider that SE 4075 filter.....
-- Lugia

So I read over your advice. Thank you very much for taking the time to look at my rack.

I did some looking around, but I really couldn't find a filter that struck my fancy in a way that would make me say "I'd totally ditch the 4075 for this". I'll do some more looking and hopefully come across something. I have plenty of time to shop, as my plan is to purchase one row worth of modules first and then a second wave later, and the 4075 or whatever I get will be part of the second wave of modules. The Lifeforms Binary Filter will be in the first wave, so I'll have that to play with.

The 2hp mixers....holy shit, that's good advice. I did exactly as you said and put five of them in the system in place of the Studio Electronics mixer (I spread them out so one's adjacent to the oscs and the disting with a final one after the wavefolder). I also decided while I was at it to drop one of the Dixie II+s to just a Dixie II and added a 2hp comb filter as well.

Where do I get the Happy Nerding Isolator? I didn't see it listed on Analogue Haven, and I also didn't see anything from Happy Nerding on Perfect Circuit Audio. Searching it on Google yielded a lot of pages in German. I'm keeping the Lifeforms Outs there just as a planning placeholder until I figure out how to secure an Isolator.

At what point does a CV signal get so spread out that a buffered mult becomes necessary? I've been building with buffered mults because I really have no idea how many times you can split before you need to use a buffered mult.

I did contemplate ditching the MIDI interface, but decided that I'll hang onto it. Reason one is that it offers much more control from a single channel of MIDI than my other converters. Reason two is that I'm sure I will eventually get around to getting modules that call for clock signals. I do have a 7' tall 19" rack in my room that will eventually become home to a few rows. I'm just opting to use the RackBrute so I can have this first system set up on my desk.

Finally, I did some rearranging after all of the above. My audio train is longer than my control train so some of the audio modules had to be left on the top (specifically the Quad VCA and the Reverb), but everything else in the audio train is on the bottom and the entire control train is on the top.

Once again, thank you for taking the time to look at my rack.

Schneider's Buro shows the Happy Nerding Isolator on their site, but lists it as 'coming soon' in its status bar. My guess is that we'll see it available right after Musik Messe, which should be in mid-April. IMHO, something like that might be worth the wait, plus if it's in your second buy, it should be on the street by then.

Buffered mults...well, when you need them depends on what you're splitting up the voltage TO. Some modules drop the voltage worse than others, depending on the impedance loading at the CV input. But since we're dealing with three Intellijel VCOs and a MakeNoise Mysteron, I'm not inclined to think that either David Dixon or Tony Rolando would design something with crap loading on the inputs. Generally, the rule of thumb should be that once you pass six splits, then you need to regenerate voltages, but some VCOs...not these, though, I'm sure...can be problematic in a split between just 3-4. If you're still concerned, just drop one of the buffered mults; this leaves plenty of regenerated signal off of just the one remaining. Mind you, the critical need for buffered mults only really comes into play when you MUST have the same exact voltage scaling between the splits; if you're splitting gates, triggers, or non-critical signals like LFOs or other modulation CVs, they're not all that necessary.

ooooo...comb filter! Have I got a filter idea for you: a Doepfer A-106-1. Sallen-Key pair, like in the Korg MS-20, but with a sick little twist: an insert point in the resonance circuit! Now that little detail opens up a lot of weird stuff, especially when you drop a short delay into it like...well, a 2hp Comb. What would be happening in such a configuration is that the regeneration for resonance is being delayed by a teensy bit, causing the whole filter setup to 'whunnnngggggg' very strangely, creating (in theory) another resonance structure in the path. I like this filter...I've loved the nasty, alternately fat and yowling character of the MS-20 for decades (and Dieter claims his version is even grittier and nastier than the original!), and having something utterly insane like that insert is a bunch of plusses. Another bit of filtering bad craziness is the Mannequins THREE SISTERS...formant-structured, but with this odd 'centre' input that causes the formant spacing control ('span') to go into warped FM-type behavior in the filter circuit. Consider: mult your input signal to that, and split one feed off to the Comb, then send it from that into the 'centre' input. Wooooooooo.... Happy Nerding, also, has an unwell filter, the MMM VCF, that allows you to either use it as two ganged state-variables (that also happen to have a 4-pole LP out, atypically)...which you can also feed into each other in various configurations to create some very weird filter behavior, plus the Comb can be linked into that sort of a signal tangle to make things even more unreal. Basically, anything that lets you subvert the normal filter behavior in some weird way or another, like those three examples, might be the sort of thing you're looking for. Loads of abuse potential...just like adding those 2 hp mixers; a little alteration in the way of thinking about the signal flow can yield amazing results, very unlike the things you find in a typical analog modeller.

EDITED Mar 16th 2018, 04:28

Good call on the A-106-1. I'm actually probably going to sell my MS-20 Mini so I can have room on my keyboard stand to set up this rack (It's a pretty sturdy stand which will hold a RackBrute 6U without issue). If I'm satisfied with the Binary as a "bread and butter" filter, I'll go for the A-106-1.

I've actually had a love-hate relationship with the MS-20. I can get interesting sounds out of it, but it has always left me wanting more options (the filter just begs to be fed oscillator sync, just as one example). This seems like a great way to have my cake and eat it too.

Below will be my first wave of purchases

EDITED Mar 16th 2018, 17:32

From the examples I've heard, the A-106-1 is every bit as capable as the v.1 MS-20 filter (same as both MS-20s I used from the end of the 1970s to the mid-80s, then from the early 90s until this past year) which is the same as the Mini (and, I'll also note, the Mini sounds like that first MS-20, fresh out of the box in 1979; many people claiming the Mini doesn't sound like a 'real' '20 are not taking component aging into account and probably have never heard one back during its original retail availability)...and those are super capable when prodded the right way. It can boom like a mo'fo in the low end, sound bubbly in the mids, and tear your head off up high. And yes...that's the point behind the A-106-1; Dieter wanted a Sallen-Key pair that was 'more'. The insert point evilness is just the cherry on that cake, but having all of the FM capability already puts it beyond the MS-20's Sallen-Key pair.

One other thing...if you're doing the Rackbrute, have you considered coupling it with something like a Minibrute 2s? The pairing is a natural, plus since your 6u is all voice, linking it with that sequencer + some extra patchpoints for $649 seems like it would make sense. It's definitely on my list to do here.

In the short term, space is finite so I really wouldn't have room to accommodate a Minibrute 2/2S and the Rackbrute on the same stand (I'm probably going to have to do some engineering to secure the Rackbrute to my keyboard stand). In the long term when I finally get around to rearranging my studio I'll probably connect the Rackbrute to another Rackbrute =D

Not a bad idea, that...Arturia really hit a home run with this system. Built-in handle, mateable to the new Minibrute 2 versions or another Rackbrute, and the whole mess folds up with the support stand turning into a handle for the whole contraption. But the reason I was thinking that might work is that you can attach the Rackbrute to a Minibrute 2 or 2s, letting it sit on the stand, and then have the Rackbrute on its attachment above the Minibrute. However, I'm not quite sure how the back supports of the Rackbrute stand will work on a typical keyboard stand; my plan is to have it on a flat surface, which is how I'm usually seeing it set up.

Just wanted to let you know I decided to go ahead and pull the trigger on the entire system as configured in the link (or hopefully pictured if the top picture has updated for you).

I have a 19" rack tower (about 2 meters tall) and have decided to build into that rather than a RackBrute. Lost some space, but building into a rack that can accommodate 13 rows of Eurorack on one side will be years of joy.

I'm a little impulsive, so I wound up going for the Pittsburgh Modular Outs because I couldn't find anywhere in the US that even had the Isolator listed. I'll pick that up whenever it finally comes around.

I dropped down to 3 2hp mixers because I wouldn't have sufficient power connectors. I also got mixed reports on whether or not a buffered mult would be necessary (some people agreed with you, some people said they had problems with splitting), so I went ahead and got two in addition to a passive mult. If the passive mult or stackable cables wind up working for pitch CV purposes, I'll probably swap out the 2nd buffered mult with another 2hp mix.

I totally went for the A-106-1 filter and will have the 2hp comb filter right next to it =D

I also decided I would bypass the MIDI interface and just got a second SQ-1. I also swapped out the Make Noise Function for a Batumi.

So thank you for your advice. It was absolutely influential on my final system and will continue to influence my decisions in the future.

EDITED Mar 22nd 2018, 00:49

Hey, the sheer allure of 13 x 84hp is hard to pass up! Can't blame you there...

Yeah, saw that build in the other thread...it's a LOT tighter now, and with the plan to expand, it's going to grow into a veritable kaiju monster of noise over the next few years. A helluva start, to be sure!