Voltage Standards

So while trying to build a poly for a while I’ve run into a few problems here and there, and because I’m never sure I am doing it right, I thought I would ask and just see if I’m missing something.

Basically there are two voltage standards in eurorack: -5 to 5 volts and 0 to 10 volts. My question is, do you guys use them interchangeably in your system? Or do you focus on one standard and get modules that use that same standard?

I know you can use bias and polarizing modules, but if you are driving 4-16 signals that’s just a non-starter. All that space for those modules, just seems to be the height of waste.

Of course if sequencers and midi to cv were built with both standards in mind it wouldn’t matter, but I don’t think that is a cost effect expectation from a manufacturer either.

What do you all think?

That’s surprising. Do you have a lot of CV inputs without an associated knob for offsetting? :thinking:

So for me the nexuses of my setup are the 301 and SSP. The 301 handles it all, but the SSP only does -5 to 5 volts. You can offset/bias incoming signals there, but that still means you’ll only get half of the octave range. So for full compatibility I have to cater to that need.

To me it just seems ridiculous that this is even a problem. Seems like quite a few things use 0-10 volts, but even more uses -5 to 5. But why does the manufacturer even have to worry about something like this? Why is this a standard that was ever deviated from?

Haha. Sounds like you are being very loose with your use of the word “standard”. I’m sure you already know that there never was any real standard and all of this has just evolved organically.

And to be honest, this kind of voltage range matching problem has only really become an issue as more and more digital modules have come onto the scene. Analog modules (almost by definition) can accept and work with inputs anywhere between the power rails (-12V to 12V minus a few volts for any non-rail-to-rail op-amps). Digital modules on the other hand, have to work with the range limitations of their ADC stages and consider how to distribute their limited bit-depth across that range. You can either provide an analog offset control before the ADC (like Synth Tech) or you can use ADC that support a very wide range (-10V to 10V) and then do the offset in software. Obviously, using a limited range ADC and only providing pre-conditioning in software is not going to “play well” with the other kids on the chaotic playground of eurorack.

I would like to also add, that I do not think a standard is possible here. Sure you can survey the field and come to the conclusion that 80% of all oscillators are -5V to 5V and 80% of all sequencers are 0V to 8V and so on but you should not use that to design the acceptable range for your CV inputs because people will be mixing these signals together in arbitrary ratios.

No, I didn’t really know that. I don’t think that excuses the need for a standard though. Especially as digital modules become more prominent.

Maybe it is just because I am not accustomed to needing a module whose sole purpose is to permit another to work with something else in a much more basic way than even a midi to cv converter which permits something not even in the same format to work with eurorack. This makes a rack unnecessarily cluttered, and needlessly complicates the patches.

I don’t really fault any of the digital manufacturers either. You can compensate for every situation but that adds to the cost of the module, especially if you are using higher level sample rates etc.

This particular problem is getting solved for me, but I don’t like being limited on module selection because of a problem that shouldn’t exist to begin with.

Just my 2 cents.

Thanks for the feedback! And kudos to you for making the 301 oblivious to these things! :+1:

I can of course see the argument of not using digital modules unless they take this (handle all voltages that analog modules can) into account being a real come back, and will say, I can’t argue with that.

We can probably improve this statement to make it less digital vs analog:

“You should handle all voltages that a eurorack mixer or VCA can output without distortion.”

This version of the rule gets at the underlying physical reason better also.

Lastly, if I may add something on the softer fluffy side that has always helped me immensely as a module designer. Do lots of Krell patches. You will learn (or at least I did) that you don’t “drive a module” with the output of another module. Instead rather, each module tunes into the signals presented at its inputs, searching out and then focusing on the sweet spot. This “tuning in to find the sweet spot” is (to me) the most basic operation of the modularist. In other words, the modularist applies his aesthetic sense at the input not at the output. Ignore this at your own risk. :laughing: (Obviously I mean this in the most subjective manner possible.)


I think it might be a matter of how you see your modular and the electrons that are flowing in it. To me utility modules for offset, attenuation and mixing voltages are an essential part to tune everything and find a nice and interesting balance. I like the old fashioned approach. Though it is indeed not easily compatible with something like polyphonic playing. To me the issue seems to be that modern module designs tend to get away from that and especially modern digital modules become more of complete/complex synthesizers or effects with CV control and the ability to mount them in a new rack format instead of using MIDI and a 19" studio rack. Not that this has to be a bad thing but it seems to break the mold of what is practical with a modular system.

Yeah I’m of the mindset that modular synthesis does not have a mold. That is kind of the point. I see what you mean with utility modules being crucial though. Discounting their utility (no pun intended) is probably not a good idea.

This is one of the reasons I like the ER-301 so much, it makes all the variances disappear.

I am sure it’s been mentioned before, I’ve gone on about it here and there, but to get extra fine control just stack a couple of VCAs. The first gives you course control, the second gives you fine control within the range set by the first - really simple, but really nice for those occasions when you need it.

I agree… completely! But it does make me curious about some of the design choices in some of the units, for example, what is the rationale for the level control at the output of the oscillator units?

Not saying there’s anything wrong with this, or that I want it to change, it just seems like the opposite of this philosophy and I often find myself ‘going back’ to the oscillator to make adjustments so I can return my focus to the inputs.


Neil forced me to put it there so that he would stop blowing up his speakers. :laughing:


Oh yes - I remember now!! :smiley:

Thanks for the reminder… As I say, no need to change anything

that is why i think polarizers, offsets, attenuverters, rectifiers, comparators etc etc are the core of a modular system. if you go the “one manufacturer - one system” route then voltages play nicely together…but, to be perfectly honest i then have more a feeling of using a fixed architecture synth with patchpoints rather than a modular system. the beauty, at least for me, is to make things fit, to bend voltages the way YOU need them. the krell example brian wrote about is a really good example, it’s like playing jenga. the way i “play” my modular is basically to have all my fingers near these utility modules and then try not to break the patch. the most satisfying and also the most random/boring patches come out this way. in a way these missing standards keep me loving the modular synth, it forces me to really build my own sound. the only standard that should be implemented imo is the ongoing power problem with eurorack.


I totally see your point! I just think when trying to do poly, it’s just not realistic or economical, and the depth that it brings to the sound, etc. is subjective at best.

I do have another 3U I’m thinking of just loading up with some stuff, and just be done with this. I’m just stubborn.

We just need more utility modules that were designed for poly patching! :wink:

Pretty soon @anon83620728 will start talking about Argos Bleak. :laughing:


Except inside the ER-301 - then it’s super straightforward, you have endless utilities and with the recent performance improvements 10 voices is well within it’s capabilities. You can even patch up chords using a single melody line to drive them - all it takes is some imagination and some clever routing.

Haha, just seen your post @odevices, Argos Bleak is pretty darn crazy (it is IME after all what else would you expect?), but also Teletype, Ansible, Endorphin.es Shuttle Control, even MI Yarns - they all provide excellent polyphonic opportunities! Teletype is off the charts… really not a problem to program complex polyphonic arrangements over i2c.

I agree about the power issues… sheesh! It can a nightmare… I am lucky in that I don’t really have any issues, well, one or two very specific use cases for one r two modules display undesirable behaviour when patched and set in very particular ways, but the issues are easily overcome with a little more patching.

I’ve struggled with this a bit myself, @2disbetter. I have been a keyboard player for many moons, and with modern digital keyboards and VSTs, I am rather accustomed to having any patch that I make having somewhere between 12 and 128 poly just gifted to me without having to do anything special. Coming into the modular realm where getting duophony can sometimes feel like a lot of work feels a trip into the history books at times.

So though I’m not taking the same path, I’m on the journey with you in a way. One thing I try to keep in mind is that I still have my keyboard synths and VSTs. They still work and sound great. So if high polyphony is a need, why wouldn’t I just use those rather than trying to tediously get the modular to have 4 or 6 or 12 of the same voice? Chords or even entire tracks could be recorded into the 301 and further processed in the modular doing the things it’s good at that would be very difficult on a fixed arch synth.

I know I’m going a little sideways on your original question/post. And I’m not saying building poly patches in Euro is not worthwhile, at least at times. It’s an interesting topic for me, and always interesting to hear how others are approaching it.


It is a good point for sure!

Before I decided to get into modular synthesis, I had been peaking at it, and reading up on it for years. For me, part of understanding the inner workings, led me to believe that there was an ultimate solution. That solution was actually just whatever synth solution meant the most sound molding options. The solutions that didn’t close any doors, so to speak. Modular synthesis seemed to be that solution.

So when I started building my eurorack, I saw how against digital everyone was, because it violated some arbitrary notion of what modular synthesis was. To me though it is not only necessary but crucial to accomplishing my goal. Can you use a VST on your computer to accomplish a lot? Absolutely, but getting that to integrate with the modular, which is the bedrock of options, is not a given and is expensive.

I’m not loyal to any one format. I’m just trying to accomplish/reach a goal. While I think in the long run digital will do everything, and do it way better than anything else, right now the hybrid analog / digital eurorack is just the ultimate synth I’ve been looking for. Poly is just a big part of that.

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A little 10kHz at full-scale never hurt no-one! :wink:


I can’t stop thinking about this, I need to explore that approach more…