Tiny experimental-ish rack

Hi, I am new to modular synths and trying to build my first one.
Since my synths follow the “east coast” model (vco, filter, eg, vca), I’d like to attempt a different approach, adding 2 VCOs, one LPG, some wave shaping and modulations and an EQ to experiment with white noise (I have seen it on internet and sounds cool).
Clock and sequences are all handled via midi, so I can integrate the synth in my setup (Behringer crave, nord rack 2x, volca beats and bass).
Also I have only 60hp to start with, but I will build another 60hp case for future expansions, so maybe I should avoid large modules (just a thought)
Any suggestion? Does the rack I have put together make sense?

Thanks a lot for your help
Love
F
EDIT: added a complex vco (feedback two59) and removed the doepfer and the EQ. Not sure it works better? I also have 4hp free...any idea please, I am not sure I know what I am doing

EDITED Oct 19th 2020, 15:11

Well I managed to significantly increase the price, but from what you've said you want I'd start with the below:

Quick notes:
1) I personally wouldn't want a system, small or not, without a Maths or similar function generator. It does too much, mixing, modulation, attenuation, subharmonic generation, etc. There are a lot of days where it's my favorite module.
2) Disting is a great swiss army knife in a small rack and will help you understand what you want in that second rack while adding lots more range to this one.
3) FX Aid is one of the top FX modules with a bit of a community around it, for 1 HP more than the Pico FX which is a lot more limited.
4) Links can work here as your mult (not sure that's needed though?) and also as two different mixers for both audio and CV.
5) I'm not super familiar with Sinc Bucina but NE make good stuff and I think this fits your criteria in less HP than Doepfer.

Thanks for replying.
There are tons of alternatives out there, sometimes you don’t know these exist (that’s why forums are great I suppose)
So, surprisingly I understand a bit of what you did.
I see the structure complex vco, lpg,wavefolder, mixer, dsp.
I was looking at disting as it seems very useful to have a precision adder when playing with FM (it does also things I don’t quite get, but that’s the pleasure of exploring). So I am happy to know that I was looking in the right place for that.

Just a couple of questions:
Do I need another vco to modulate the two59 and for FM?
What’s on duty as LFO/random generator Would it be the maths?

Thanks again
F
EDIT: the multiplier was meant to be used to send the clock to multiple modules, not sue now I need it(maybe it is still useful to have one)?

EDITED Oct 19th 2020, 16:48

No surprise that you grok'ed it, you seem to have a solid foundation!

In this setup, you can use both Maths and the Disting as FM modulators, each can do both audio rate oscillation and LFOs. For random, you'd want to use the Disting here as it has a couple random algorithms.

One final note, you also get a Precision Adder in Links, so thankfully you can use the Disting for other things.

See below for an overview of Maths, and another for Disting though they've added more algorithms since this one was made:

EDITED Oct 19th 2020, 17:16

All very interesting! You are right, maths and disting are like Swiss Army knives and are probably worthy every penny spent to buy these.
I am probably in love with the complex modulations you can do with maths.
I am also wondering what happens if I feed the envelope follower with some environmental percussive noise lol..would I need some sort of signal booster for that, or the attenuverter in maths is enough?
External audio signal is low compared with oscillators, isn’t it?
I will definitely keep an eye on those 2 modules.
They seem pricy, but they are probably relatively cheap, compared with what I would spend to buy single modules for just their main functions...

Once again thanks, speaking with you is super useful!

F

Input and output are interesting in a tiny rack like this. For output, I chose to lean on using one of the Maths attenuators as your output (you'd need a 3.5mm to 1/8" cable, I think this would work from prior comments by @lugia) or would suggest an external mixer. For input, I think you'd want to sneak in a dedicated module, for example the Mutable Instruments Ears. I don't process external sources though, so I'm not an expert on that one.

Glad this has been helpful, others may chime in too but either way keep us updated on your journey!

I've been using a Doepfer A-119 input with envelope follower. It's great and very inexpensive.
https://www.modulargrid.net/e/doepfer-a-119

Yes, I have noticed that doepfer generally has more affordable modules. On the other hand they tend to have 1 function per module. I mean, to put together the equivalent of a disting I would probably need 84hp.
They sound great for what I have heard, though.
The envelope follower is interesting, I think I will leave it aside at the moment, depending on how far I go with the idea of integrating other sounds/instruments in my setup.
At this stage I have only built the case out of a plywood sheet and a synthracks frame And today I purchased the power supply...soooo....1 module a month...I can’t wait for the next one. Hopefully with this approach I will have time to explore each module and get a better understanding of what it does before adding the next one

Took a whack at this, although I didn't bother with the 1 x 60 idea at all. Too small, really...you COULD probably jam all of that into 60 hp, but this 2 x 60 variation shows where a build like this could go...and it might be something you need to be thinking about right now, because if you have an indication that you might need to go bigger, you should DEFINITELY follow your gut and build THAT.

OK, let's look at this thing. First up, the layout is VERY different. Most of the audio (except the noise/EQ setup, more on that in a bit) is in the top cab. After the P/S (went with 4ms Row 25s here...ample current, plus easy daisychaining from just a single external "brick") you have a NLC input module with full envelope following. This then has a Warps next to it, primed to scramble the hell out of any external audio as needed. A Klavis Dual Waves gives you your two VCOs...albeit these also have some interesting extra features, one of which is internal quantizing (with several scales). Intellijel's new dual wavefolder is after this, offering dual inputs so that you could ALSO use the wavefolder as a wave-mangling 2-channel mixer. If not, then you can just as easily use the Optomix (your LPGs) for a "clean" mix via two LPG inputs and a third fixed-level AUX in. A Happy Nerding 3xVCA gives you breakout-able VCAs and/or mixing for your audio, then this outputs to the Purrverb digital spring, since spring reverb was a big part of the Buchla sound, especially in the 100 series. And since this can go mono-to-stereo, I put a Happy Nerding Isolator in as your stereo output level control, plus it offers transformer isolation, which can be a major asset if/when gigging...plus you can push the transformers a bit for a little more warmth via a bit of saturation.

Bottom row: after the other Row 25, you'll find an Expert Sleepers FH-2. Not only is this a user-configurable MIDI over USB interface, it can ALSO function in USB host mode, meaning that you can grab this, a USB-MIDI controller like a Keystep, and you've got your "go kit" since you can jack the Keystep (or any other USB controller) directly into the modular. Then, Maths. Of course. An After Later DVCA (1/2 of a Veils, basically) gives you curve-adjustable VCAs for either audio OR CV/mod level control. Then a dual ADSR for "normal" envelopes. After this is your "noise voice", which starts with Doepfer's A-118-2, and this also provides a random voltage source, an extra clock source, track and hold, or sample and hold...all of which will definitely be of use for the entire rig. The noise can feed on to the EMW Fixed Filter bank...which not only gives you graphic EQ-type timbral control, it ALSO has individual outputs for each band! And you can feed that to either the 3xVCA or the Optomix.

This is a much better look at where your build should be heading, according to some indications you gave about the 2-row upgrade. I simply opted to do that in THIS build, which hopefully gives you a much clearer idea of how to proceed so that the jump from one to two rows isn't such a hassle. Hope this helps!

Thanks for your contribution Luigia.
Here I see a few interesting diversions I will certainly explore.
the idea is to expand the setup over time.
Music is my (potentially bank-breaking) hobby, therefore even if it probably wise to think bigger from the beginning as you suggest, I am not in a rush and can consider the direction I want to take while I am on my way.
I will take some time to analyse the info I have so far and see what I come up with (When I was talking about equalising white noise I had in mind something with individual outputs which I could mix with an external mixer....you really hit the nail with that)

Thanks
F

EDITED Oct 21st 2020, 15:33

Yes, I have noticed that doepfer generally has more affordable modules. On the other hand they tend to have 1 function per module. I mean, to put together the equivalent of a disting I would probably need 84hp.

-- Startics

more like 8 * 84hp - average size of doepfer module is about 8hp - and there are over 80 algos

what puts people off disting a lot, is if they try to test everything, constantly and have to refer back to the manual everytime to remember what every input and output is doing... if you set it up to use favourites - say a dozen algos, and then concentrate on those and replace the algo with a dedicated module, say you find 70% of the time you are using disting as a delay - buy a delay and replace the delay algo in favourites - it is much easier to work with - the menu is about as deep as a puddle!!

just to add to what Lugia said - you could probably get away with a single rack wart (power module) to power both rows - although much easier with a single case

sometimes when trying to do things cheaply you need to spend more upfront to actually make the savings in the long run - it's like buying from a warehouse store (like costco) as opposed to a deli - work out cost per hp for the DIY powered case - and then work out how much a Mantis costs (I checked Mantis at sweetwater the other day at $335/204hp = $1.60/hp ish) and it's a respected case with good power etc etc and it's still portable, unless you are a small child

the easiest way to make a small eurorack system is, like how to make a small fortune, start with a big one!!!

Yes, I concur with your approach to disting. I believe also troux suggested that module to try new functions and decide what will need in the future. So that’s a big yes

Re the cases, that’s purely the pleasure of diy (I took that from dad :-) I could have done it 84hp to start with but ok, I can build an 3-tiers rack 84hp per row with less than 100 pounds probably and stick inside a doepfer power supply and save so much..even though the main thing here is the satisfaction of doing it.

Thanks
F

couldn't agree more - I have 4 cases of which 2 are DIY (both 9u/104hp) - rails, threaded inserts, screws and wood - about 110€ each - power is where the cost is - the Doepfer PSUs are good - but often stretch at 9u/84hp due to modern digital modules - I'd pay attention to power draw if I were you!!

Yuppers...ALWAYS watch your amperage loads! I usually tell new builders that they need to install a power supply that can provide at least 25% more (and preferably 1/3rd more) current than the modules connected to it require. The reason is due to "current inrush"; when you first power on ANY circuit, there's a tiny interval where the components can draw more than the module's "operating" current. If that exceeds the P/S rating by TOO much, P/S go "pop!" And P/S go "pop!" isn't good, because different supplies can do various destructive things when they fail. If you're lucky, nothing happens. If not, you get some horrific spike across a DC bus that wreaks havoc on the whole damned build!

The other reason for overspeccing the power is heat. Heat gets generated by power circuits in direct proportion to current draw if the voltage is fixed. And heat in a synthesizer is NOT a good thing! Not only will it contribute to tuning instability and potentially increase noise factors, heat over long periods gradually causes component breakdown. And this is worst in the P/S module itself, which is also under the heaviest burden due to what it's doing. By going with a P/S that has considerably more current potential than is needed, the P/S can loaf along under a much easier load, and this prolongs its life and, by extension, the entire build itself.

Ok, you definitely have a good point. I got a question on this topic: would it be a good idea to drill a hole in the case to allow air to circulate better?
Given the power required by my small case I believe I could be ok with 2000 mA, which should allow me to power 120hp with no problems. Am I right?

Thanks
F

EDITED Oct 21st 2020, 15:33

by the look of it one of those row power 25s is powerful enough to power all 120hp

Ok, you definitely have a good point. I got a question on this topic: would it be a good idea to drill a hole in the case to allow air to circulate better?
-- Startics

Nope...try to avoid messing with the integrity of those Moog skiffs. They're pretty beasty, and drilling into them would sort of waste that.

But what I WOULD suggest as a solution, since the Row 25s have so much "uninvolved" panel space, might be to add a little heat sink of some sort to the front panels of each one. That way, heat that could build up on the front panel (many little P/Ss do this...the uZeus, in fact, has a little warning about the excess heat on the front panel) would instead be dissipated. And since metal transmits heat better than air, that ought to draw the heat off admirably. Just make sure to use a little bit of the same sort of heat transfer paste you see used to seat heat sinks in computers before epoxying the heat sinks down...heat paste in the middle, epoxy bits at the ends, and that should be golden.

“Nope...try to avoid messing with the integrity of those Moog skiffs. They're pretty beasty, and drilling into them would sort of waste that.“

Ehm...Moog skiff? That’s not my..case..(lol). I have actually build it with plywood, it is deeper than the usual skiffs you can buy around, as I originally thought to fit in some doepfer modules. It could be easy to cut it and cover the hole with something to avoid dust getting in

But I get your advice, I should definitely go for a 4ms or maybe a Koma Strom PSU, they have passive expansion. Probably the ideal solution to power just another 60hp row.

EDITED Oct 22nd 2020, 00:50

The Koma ones are 100% recommended...the Strom+ has plenty of juice, plus I like the 4-pin Molex linking method. The only reason I didn't go with them is that their availability can be a bit erratic; it's probably best to try and get their stuff either direct or from someone in the EU like Schneider's.