Please evaluate this A-100 (Doepfer) system

Hi folks,
I hope some seasoned modular moguls can take a look at the system I'm designing and offer feedback. It's 15U spread across two cases (a Doepfer low cost case (9U) and low cost base (6U)) as seen in the following: (Edit: the bottom case doesn't seem to be displaying in it's most up-to-date layout; clicking the link should display the updated version)

The aim guiding the design involves: the ability to generate a broad palette of interesting "experiemental" and evolving timbres and textures; generative patches; loads of modulation; loads of flexibilty; both control and room for the unexpected; a unique, personalized instrument.

Do you reckon this 2-part system can satisfy the stated aim? Any obvious omissions or redundancies? Something I might have overlooked?

Thanks for your time,
wrecksmoondee

EDITED Jan 8th 2021, 00:05

Hi wrecksmoondee. Looks like you have just about everything you'll need. Maybe some exponential VCAs (unless I overlooked those) and additional attenuverters, though the matrix mixer may work for inverting signals. Will you be adding any external effects?Also curious if you are only interested in Doepfer, or will you be researching other manufacturers too? As much as I really want that A154/A155 combo, but there are very capable sequencers in a much smaller footprint.
You are off to a great start here, though I wouldn't recommend buying everything at once. If you just buy a few modules at a time, that will give you the opportunity to adjust your plans on the fly to incorporate modules that may be a better fit for the type of music you want to do.
Have fun and good luck!

Hi wrecksmoondee. Looks like you have just about everything you'll need.
You are off to a great start here, though I wouldn't recommend buying everything at once. If you just buy a few modules at a time, that will give you the opportunity to adjust your plans on the fly to incorporate modules that may be a better fit for the type of music you want to do.
Have fun and good luck!
-- farkas

Hi farkas, thanks a bunch for your feedback.

Maybe some exponential VCAs (unless I overlooked those) and additional attenuverters, though the matrix mixer may work for inverting signals. > -- farkas

It's true, no exponential VCAs here; I'm hoping to get by with just linear, I guess. Is that feasible? If not, what should be dropped instead? There are a few polarazers there and I also have a couple some passive attenuators (basically little external patchable volume knobs) that I hope will do the trick for inverting and/or attenuating signals.

Will you be adding any external effects? -- farkas

I have a few quirky pedals that I plan to bring into the signal path: Chase Bliss MOOD, Pladask Fabrikat, Red Panda Tensor and Particle.

Also curious if you are only interested in Doepfer, or will you be researching other manufacturers too? As much as I really want that A154/A155 combo, but there are very capable sequencers in a much smaller footprint. -- farkas

Currently, I'm planning to stick with Doepfer; this for reasons both strategic and aesthetic. Strategically, I hope that sticking with Doepfer will be a buffer against getting lost in a constant search for novel modules--there's just so much out there and I would always wonder if the next thing is better for me. And I bet there's a lot to discover right here. Strategically, too, I think working with Doepfer's building blocks will provide a deep education in modular synthesis and "patch programming". Aesthetically, the look and consistency appeal to me. I reckon it's like how some folks dig going for all Serge or all Buchla or whatever.

Thanks again for your feedback!

Sounds like you have a great plan, and I'm sure this system will give you many years of excellent service!
I only have a few Doepfer modules myself, so hopefully some of the other users will chime in with specific module recommendations (or warnings).

Sounds like you have a great plan, and I'm sure this system will give you many years of excellent service!
-- farkas

Cheers mate. As you pointed out, there are no exponential VCAs here; I'm hoping to get by with just linear. Based on your experience, is that feasible?

I'm not sure if my old ears could tell the difference, but it may be nice to have the option. Lugia could probably break down the science of it for you, but changes in volume sound unnatural with linear VCAs if I remember correctly. Here's some additional info:
https://learningmodular.com/linear-versus-exponential/

Start off with the linear VCAs, and if you decide you need exponential, that's what you'll end up buying next. The beauty of modular! :)

Have fun.

I'm not sure if my old ears could tell the difference, but it may be nice to have the option.
-- farkas

I think that the VCA portion of the A-101-2 Low Pass Gate is exponential, so that ought to at least give me a sense of the flavour and provide the option if needed. Thanks for pointing me towards more info!

When I took my first tour of modular synths back in 1998-2002, before taking a break from making music due to life factors, I had a Doepfer system of this same size. It was terrific, and this looks terrific too. And I think you're right... having one manufacturer to focus on takes some of the G.A.S. out of the equation, and also makes the system look and feel cohesive. Enjoy!

My concerns here are that there's too much attention being devoted to aesthetics and not enough to functionality. Doepfer modules are really excellent...but they're often pointlessly big, an issue which Dieter has been working on fixing with the new, smaller modules.

Take the A-141-2, for example. ONE single CVable ADSR in 14 hp, costs $190. But then, look at the Livestock Leap...also one loopable and CVable ADSR, but which ALSO offers offset and inversion. So, right there, you'd wind up eliminating the A-141-2...AND the A-183-2, AND half of the A-133. And it costs $5 less.

The real power in Eurorack and the plethora of modules that exist for it is in being able to mix and match things. Sure, it looks cobbled-together that way. But you can effectively jam MORE functionality into the same space, and in quite a few examples, you can save money while doing that. I wouldn't suggest making the various modules smaller in this size of build...but I do suggest that you can wind up with a far more potent system by NOT locking yourself into a certain "look", and building more along the lines of maximum capability. In the end, nobody cares what your system looks like, but they sure as hell will know that building for more function will equal far more musical flexibility...and THAT is what an audience looks for.

Oh, yeah...explaining linear and exponential...with LINEAR VCAs, envelopes, etc, you're imposing a change on a signal that follows voltage scaling. If you need to change the voltage scaling so that everything still tracks properly as far as CV values, you use those. It's also why linear VCAs are almost always DC-coupled, because they fit better at modifying CVs, modulation, etc. EXPONENTIAL VCAs, envelopes, etc, though are AC-coupled, as exponential relationships are what governs how we perceive "apparent loudness". Remember: the decibel scale is a LOGARITHMIC curve of values, and NOT linear. Note, though, that you can get away with only linear VCAs in a build as long as you have exponential EGs to make them conform to the exponential loudness curve. See here for a more in-depth explanation of this: https://en.wikipedia.org/wiki/Loudness

My concerns here are that there's too much attention being devoted to aesthetics and not enough to functionality.
-- Lugia

Thanks for your feedback, Lugia. I hear you, and I reckon that I could cram more in a smaller space by mixing and matching. But given what I've presented here and the stated aim, am I actually falling short functionality wise in the sense of failing to realize the aim?

To fill in the background a bit, I can confirm that I will be the only audience; this is a hobby instrument for my own pleasure, so aesthetics has its place; and I think the risk of an endless search for novelty/increased functionality is a real one--folks confess/lament it frequently, so I think a strategic buffer against that (by aiming to stick to Doepfer) might be wise.

Note, though, that you can get away with only linear VCAs in a build as long as you have exponential EGs to make them conform to the exponential loudness curve. -- Lugia

Any insight into whether these Doepfer EGs are exponential?

EDITED Jan 8th 2021, 03:55

The only thing that I can see that's got an exponential response is the A-138 in the lower cab. However, since most everything IS linear, what you might consider would be to yank the A-130-8 and replace it with the A-132-4. This is a similar module with four exponential VCAs, and losing the other four linear VCAs really wouldn't be an issue if you dropped the A-138u for an A-132-1 to replace two that you'd lose. This would then give you six linear VCAs and four exponential.

Another idea would be to drop the A-138u, move the A-183-2 to where it was, then swap the A-133 for an A-133-2, thereby opening another 8 hp. At that point, you could then move the A-130-8 to that newly-opened slot and then put an A-180-2 mult next to it. This then takes you to 12 linear and four exponential VCAs...MUCH better.

I'm gonna bang on this a bit and see if I can up the functionality in some other ways as well...even while staying 100% Dieter here.


That was interesting...I still felt constrained by Dieter's module sizing + a few missing "go to" modules that weren't Doepfer, but I think these beefed up pretty nicely. Considerable changes...here we go...

ngin, Row 1: Added an external input/envelope follower for processing external sources. Then I put the buffered mult next to that, and added a dual slew limiter for portamento (#2 has direction selection). Eliminated some of the VCOs so that I could add a Quad VCO with a Quad VCA, which allows you to CV the mix of the four VCOs. A-110-6 remains, but then there's a uPVCO which is there as a "driver" for the PLL module. These last three generators are more or less intended as individual voice oscillators, but there is a small 4-in mixer there to allow mixing, if desired. After that is the Wave Mult I.

Row 2: Quad LFO with a 4-in mixer, which allows you to blend up complex modulation in a minimal space. Then the VC Delayed LFO went in, more or less an upgrade because of the delay circuit...very useful. I kept some of the quadrature functionality in with a VC Quadrature LFO; you don't necessarily hear quadrature relationships in audio, but for modulation, well...that gets interesting, with the ability to mess with phase. There's a point to it in a bit, same row. Then the A-143-1, and after it is a dual VC Polarizer, which allows you to tamper with modulation results even further. I made some significant changes to the VCF lineup, also...starting with the VC Xpander VCF (replaces the SEM VCF, as the topology for its 12 dB LPF will essentially be the same) which gets tandemmed with the VC Dual Crossfader (hence the Quadrature LFO) which allows you to "morph" between a few different VCF topologies, resulting in some potentially-complex VCF behavior that wasn't there before. Multimode VCF next, then your LPG.

Row 3: Noise/random/S&H starts this off, using that as a replacement for the original noise source to save some space. Then the VCS clones and the VCADSR. After that, I added two more non-CV ADSRs, which now brings the EG complement up to seven EGs totalled. Then the Bit Mod and Spring...although I admit to being a bit torn as to whether the Pedal Interface might've been a better fit for BOTH of these, allowing you to employ external processing for both slots. The BIG fix is next, though...you'll notice the Quad Exponential VCA right next to the 4-in Performance Mixer (and its output module). This NOW lets you have a stereo output from the synth, plus you also have an AUX send/return on the Output module so that you can parallel-process an effect (spring would work well with that). And you also get CV over your mix by patching each of the Exp VCAs to a corresponding Performance Mixer input. Again, you might consider using the Pedal Interface in both of these 8 hp effects slots, as this would then let you slot in any sort of pedal for both...and you can STILL use one of those as an AUX insert with the Performance Mixer.

ctrl Row 1: There's the A-149-1/2, then a Diode OR for combining gates...which is useful for various trickery with the Boolean logic module. A-152...then the Octal Linear VCAs, as these are better suited for CV and modulation, hence the relocation to the "ctrl" cab AND their relocation next to the Matrix Mixer, which then lets you have a similar CV capability as the audio mixing setup in "ngin"...but with VCA control over both the outs AND the ins of the Matrix Mixer itself, if you desire. A switched mult is next, which I added to help with performance-type CV bus switching on the fly. After that is the Dual Quantizer...so the Switched Mult can behave as a manual "router" for your quantized CVs between two different VCO groups.

Row 2: The clock mods are now paired with the Sequencer control for ease of patching. And the 2/3/4-position VC Switch is down at the end of the sequencer, where it needs to be to shift from dual 8 to single 16 CV row behavior.

Now...while making these changes, I tossed a lot of the less-densely-functional modules while trying to make sure that those functions were being replicated elsewhere, so that the functional density (and potential) of the build could be upped while losing as little as I could manage. A few functions didn't exactly make the cut...but not many, because once you start diving into how a lot of the added modules work and what they're capable of, you'll find that most everything from the original builds are still present...and by mashing the crap out of the space, it allowed me to drop in things that really up the capabilities of the build. Also, you'll notice that everything is function-grouped now, running left-to-right and up-to-down on signal flow. This also keeps the end of the audio at the bottom right of the "ngin" cab, making the entire "ctrl" cab purely control-dedicated. Plus, by swapping the sequencing modules to the "flat" row, you now have the system's primary controller where it belongs.

...and it's still 100% Doepfer! Whatcha think?

EDITED Jan 8th 2021, 07:13

^^ This is definitely even sweeter!

Considerable changes...here we go... ...and it's still 100% Doepfer! Whatcha think? -- Lugia

Considerable changes is a considerable understatement; it's a radically different instrument! Before I go in to why it won't be my instrument, I want to thank you for taking the time to complete this exercise--it's like crosswords or sudoku, isn't it?--as it's helpful for bouncing ideas around.

I'm gonna bang on this a bit and see if I can up the functionality in some other ways as well...even while staying 100% Dieter here. -- Lugia

So, having studied your model briefly, my impression (and this could be founded on my own inexperience) is that more has been sacrificed than has been gained.

In opting for a "larger system" (15U is nothing to sneeze at, I think) I don't think I should have to sacrifice ergonomics to the slimline series, so I've deliberately avoided those. They were designed, according to Dieter, for situations such as the little beauty cases that people like to put together. I'm happy for a few fewer, but easier to "handle" modules. And, again, I don't think much (if any) functionality is lost in my case.

Some of the more interesting VCOs that I think would have offered a more interesting timbral palette (especially the A-110-4 Thru Zero VCOs) have been lost; this deviates from the basic aim of the build, namely interesting timbral variety.

The only thing that I can see that's got an exponential response is the A-138 in the lower cab. -- Lugia

I intend to use this as the final output, plugging either a pair of headphones into here or using a longer cable with a 1/4" adaptor to go into my external passive mixer (Art SPLITMix4) which connects to the home stereo system. From what I've read online, it's common to use the A-138 as the final output. Also common, from what I've read, is people using linear VCAs almost exclusively, even for audio, contrary to the received wisdom in lin=cv, exp=audio. So I think I'm going to try my luck with linear VCAs and adapt if the need becomes obvious.

Added an external input/envelope follower for processing external sources. -- Lugia

This, instead of the FX insert that I plan to use to bring a few interesting pedals into the signal path. You mentioned you were torn about the this module, but I'm keen the keep it along with the reverb and bit crusher, which latter ought to prove interesting for cv too.

And the 2/3/4-position VC Switch is down at the end of the sequencer, where it needs to be to shift from dual 8 to single 16 CV row behavior. -- Lugia

My impression is that the A-150 Dual VCS is sufficient for shifting from dual 8 to single 16 CV row behavior on the sequencer. Is that not the case? That would free up the s/3/4-position A-151 Sequential Switch for more interesting applications.

Plus, by swapping the sequencing modules to the "flat" row, you now have the system's primary controller where it belongs. -- Lugia

I've read that the sequencer or controller may not fit comfortably in the "flat" row due to the power supply; I had originally intended to place it there until I read that. It's not a dealbreaker for me at all.

So, I want to thank you again for engaging in this exercise with me. Given my resistance to your radical revisions, I imagine it might feel like thankless work, so I want to make sure I have enough gratitude buffer in here.

I want to conclude by reiterating this general question: given the stated aim (the ability to generate a broad palette of interesting "experiemental" and evolving timbres and textures; generative patches; loads of modulation; loads of flexibilty; both control and room for the unexpected; a unique, personalized instrument), am I actually falling short functionality-wise in the sense of failing to realize the aim? I grant that the aim could be achieved differently and with smaller modules, but that's another matter.

Cheers Lugia!

>
I want to conclude by reiterating this general question: given the stated aim (the ability to generate a broad palette of interesting "experiemental" and evolving timbres and textures; generative patches; loads of modulation; loads of flexibilty; both control and room for the unexpected; a unique, personalized instrument), am I actually falling short functionality-wise in the sense of failing to realize the aim? I grant that the aim could be achieved differently and with smaller modules, but that's another matter.

-- wrecksmoondee

I think each of us has a different definition for "functionality," so your approach to a unique, personalized instrument is vastly different than mine, which is great. Yes, this will likely do the things you want unless your idea of experimental evolving textures includes sounds that you would find in something like the Spherical Wavetable Navigator, Panharmonium, Rings, or other wacky digital modules. I like some stuff like that, so your plan wouldn't be quite as functional for me.
Either way, it seems like you have a good understanding of synthesis. Dive in. Buy some modules. You'll know if your plan is a good one once you start patching. Have fun with it!

I think each of us has a different definition for "functionality," so your approach to a unique, personalized instrument is vastly different than mine, which is great. Yes, this will likely do the things you want unless your idea of experimental evolving textures includes sounds that you would find in something like the Spherical Wavetable Navigator, Panharmonium, Rings, or other wacky digital modules. I like some stuff like that, so your plan wouldn't be quite as functional for me. -- farkas

That's a good point; some of this stuff is subjective but here I am looking for an objective answer to a question phrased in objective terms. I guess fundamentally I'm checking whether there's some obvious blind spot in my plan--as is often the case in these kinds of posts from what I've seen--but I've been fairly reassured.

Either way, it seems like you have a good understanding of synthesis. Dive in. Buy some modules. You'll know if your plan is a good one once you start patching. Have fun with it!

-- farkas

Cheers farkas, thanks for your time. I hope you have fun too.

I would still recommend buying a few modules at a time and allowing for a change in plans. My actual rack is much different than my initial plans.
I’ve argued in favor of the aesthetics being an important part of modular in the past. Just as guitars use flame maple tops and drums have glitter finishes, it’s OK to want your instrument to look cool too. With that being said, if it only looks good but doesn’t have the right parts for YOUR style of music and patching, it becomes an expensive attractive paperweight. I would advise placing function over form as you begin assembling your instrument. Use the thing, don’t just look at it. And if you buy a module that doesn’t fit in, sell it for a small loss and move on quickly to something that actually works for you.
That’s about the best advice I can offer. Let us know how you progress in the journey!

Hm...about 7 this morning, I got hit with an idea about this thread. Kind of a nuts idea, but consider this:

So, you want something that's exploratory, that has an unlimited palette of sonic potential, that you'll live with and use for a LONG time without exhausting the fascination, and that's got a unified aesthetic. So, I got my dead ass out of bed, came up to the studio, and started cooking.

And cooking.

And then, it all pretty much clicked in place. Now, this blows your budget totally. By orders of magnitude, even. But it IS everything you're seeking. And it will take some time to assemble this, given the expense, unless you've got deeper pockets than most MGers. However...it's not Doepfer. It's not even Eurorack. This...

...is what I came up with. Now, bear with me for a bit...

This Serge system might seem pretty large. But it's not. Each "boat" (there's eight here) is only 17" long, maybe a couple of inches deep. And yes, you can get brackets for the Serge boats that allow pairs to fold up, so it's actually got a certain degree of portability to it. But it REALLY is at its very best when it's placed prominently in a nice space...the 21st Century postmodern equivalent to having a Steinway in the drawing room, I suppose. So this isn't simply an instrument for playing...it can be set up for generative music for gatherings, and it'll REALLY raise eyebrows with just its presence alone. So, aesthetic AF.

But as I noted before, that's not really the point. FUNCTION is the point. And frankly, you simply cannot get denser functionality than is found in Serge systems. Not even with much of Eurorack, either...because many Serge modules are capable of doing several different things depending on how you've got them patched. For example, while there's only five things labelled as "oscillators", the system here has many more things that can function as that, since even the LFO-type oscillators can track well into the audio range, and modules such as the Universal Slope Generator (yep, the core of the Maths...so the 2nd panel, 2nd row might just look a tad familiar) can also track into audio...so that one panel with two DUSGs is also "hiding" four more VCOs. Similarly, you might wonder where are all the VCAs? You only see four, right? Well...no. There's those, then the four more in the Stereo Mixer, then ALL of the modules marked as "Active Processor" are also VCA-able, plus the X-Faders work that way, too. And there's probably something else that'll do that as well...working with one of these is sort of like sculpting sound, not simply arranging signal chains.

Oh...yeah. No mults. Anywhere. Serges use single banana patchcords...which are stackable. So this thing might seem to have limitations until you realize that sources of audio or modulation can be spread across the entire system, more like building a spiderweb of signals. And really, it's more like audio and modulation sort of...break down with these systems, you don't have a clear division between the two. And that makes the potential for complex sonic exploration go right off the scale! But at the same time, you only have ONE cardinal rule: don't connect RED to RED. That's IT. Otherwise, anything connects to anything here, and functions of circuits can change just based on what you're feeding them with...and can they even change just by changing a signal's basic value: lower, something thinks its an LFO...but jack up the CV, and it's outputting audio. Or modulators turn into sound sources. And on and on...yeah, when I said "exploratory", I really meant it!

Now, yes, this isn't where this started. Not even CLOSE. And one stumbling block here is definitely the price tag. But even though this is a $28.5k budget imploder, the most expensive panel is the last one on the third row, and it's $3k because it has both the Frequency Shifter AND the coveted Wilson Analog Delay on there. Most of the rest (even the TKB Sequencer) float between around $1500-2000, which...if you think about it...if the Doepfer system I slapped together was around $7k, that amount would get 3-4 of the 8 space panels. If you can budget properly and spread the cost out over time, it really won't be that much of a hassle...it'll just take a while, with a hellacious payoff once it's all assembled.

But at this point, it probably looks utterly absurd. That's why, before rejecting this offhand, I think you should take some time, see what this can do...plus what it might do with some hands-on discovery time...and consider if this might not be what you were aiming at the whole time. Copy it to your account (and yes, it'll be fine with a non-Unicorn account), dive into the build, check out the different submodules, and start puzzling what you might be able to pull off with a system on THIS scale. It's not what you'd expected, sure...but surprises can be truly fun, and this'll have an infinite supply of surprises!

Man, that would be sweet.

Man oh man, a fellow can dream. I couldn't justify the expense for a hobby, but it's fun to imagine.

Hey, if you've got aging boomers who buy old cars and pour THOUSANDS into restoring those...and all they do is what they did in the first place (drive around, waste gas, etc)...I'd think it's a zillion times more virtuous to put that same type of money into something like THIS, get creative, and get some art out to people who can benefit from it. Both hobbies...but one has a lot more cultural potential than the other.

Ha, I think this has do go down as one of my favourite threads on here. :)

What a great read!