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User Replaceable CPU - THE DEFINITE THREAD - Which one? When? How? Etc


Still seems brilliant to me!


The idea of having a modular component that is in all cases future proof is an absurdity to me. I can buy an oscillator this week and next month when the MK2 version comes out I’m not entitled to the added functionality nor do I expect it. If I might be able to dream of the ER-301 being able to step into the future, well then that’s an incredible luxury.

If we can experience a CPU upgrade at some future point that effectively gives me a ER-301 MK2 for only $100 to $150 over my original investment instead of having to sell the ER-301 and spend $1000 for the MK2 I think that’s an incredibly smart idea. And if on the other hand my ER-301 is locked to a stable and mature 1.0 firmware that can no longer be upgraded, then so be it.

I have the Mutable Instruments Clouds, Braids, and Peaks - all three modules have been discontinued and are done being updated. I don’t feel burned because they have reached end-of-life. I didn’t buy them with the idea they’d be supported for years into the future. When Olivier releases their successors I’ll likely be one of the first to order those units too. As long as the module works as it was advertised to do, then the contract between creator and consumer has been satisfied.

So I guess there’s a truth in the statement that:

because of the negative reaction the conversation has elicited instead of my more hoped for positive reaction where as the ER-301 firmware matures and reaches feature completion that the more creative among the 301 users would have already been pushing the limits and helping scope what features and capabilities would be requirements in a future CPU upgrade.

Now we can all sit on the sideline as development goes into a kind of “skunk” mode where open conversation doesn’t inflame anxiety among some of the potential and current owners of this incredible device.

All this anxiety and fear of missing out on something over a potential upgrade that was suggested to cost what about 16 stackable patch cables cost. I’m scratching my head in disbelief.


i think this makes a lot of sense. thanks brian.




I would not say so. Of course you are right with the notion that hardware updates often tend to project some taste of obsolence - mostly to people for whom having the newest anything is important for some reason, I suppose. But as long as the MKI is fully developed, working without bugs and still supported if bugs occur I would not consider this a real issue.

Having a continuity break in a product that is also based on developing own software units on it and sharing them on a forum might provoke turbulences though. Take a look at the development of the teletype firmware, where the other Brian is very aware of e.g. keeping everything backwards compatible so that older scripts still work. Although bugfixing on the discontinued trilogy modules is very slow if anything nowadays. I see that maintaining the whole line is a lot of effort for one single person but maybe then starting a new line before the old on is fully developed is not a good idea.

Of course designing the ER-301 with an upgrade option was a great idea though. Maybe changing a hardware design before everything is mature not so much. What I appreciate very much is the openness to discuss it and clear up those misconceptions about just putting on a new board ordered from a third party for a few bucks and everything is better, as we have been used to in older computer days.

I am not sure if offering both versions would solve all this. It might stir up even more trouble when one firmware is developed further and the other is not and developing both would be too much of an effort I suppose. Also I don’t think many people would purchase the smaller CPU version. Not in the eurorack market.

I think if it is possible from an economic point I would keep a gap between the last batch of the old CPU w/ finished firmware and a new version just to prevent those who have recently bought one from feeling bad - if they have a real reason to do so or not.


After all the messages of support I have received I thought I should post publicly to clear a couple of things up:

I have reflected on what I said yesterday and it’s obvious I am not in the right place to do this at the moment, I have done this since day one, almost every day and put hundreds of hours into this. I have a lot of other things going on too at the moment, a considerable number of them very challenging. So I am definitely taking a much needed break, it’s completely 100% my choice to do this.

Of course I will be back at some point, but I really don’t like the tone of an increasing number of posts being made and I can only hope that folk take a step back as I have done and think before they post especially when the outcome is that something a lot of us have looked forward to for a long time is now being shelved. Needless to say I am very disappointed that this has caused an about turn on the hardware upgrade. I can honestly say this is the first truly depressing news I have ever had here.

Have a lovely holiday and see you sometime in the new year.


I am envious of the way Brian navigates through the thick clouds of feature requests and opinions present on this forum, learning something from each – I would probably suffer a very bad case of analysis paralysis myself.

The way I see it, I bought a module under development, which means I get to offer feedback concerning its development. But I didn’t buy O|D shares – I don’t have an actual vote. Someone else is taking all the financial risk, and it’s their product, so it’s their decision, ultimately.

Also, I don’t really get to be disgruntled about things I didn’t explicitly buy into – once the 301 hits 1.0, you’re going to have the product you bought, forever. Everything on top of that is extra – with the 301, there’s no “buy our mark 2 product, now with added features” á la Octatrack mk1/mk2, you get to have extra stuff for a fraction of the cost, by dropping in an upgraded processor. I think Brian’s way of doing this is simply, in all aspects, better than practically every other synth/music manufacturer’s model.




Very strange conversation. I don’t see any problem in the upgrade and the method how Brian has informed everyone. The “mk2” will be more expensive like Brian said and the upgrade will be available for everyone who has already purached the module for the same addition to the total cost. I bet the problem is that the guy who get offended about the upgrade has not used the module and thinks that it’s not usable without the upgrade. Hope we get the upgrade at some point and I’m already happy with the recent CPU so it’s only bonus for everyone when ever that happens.

And the Ipad reference is totally invalid in here you can’t change any part on that one and that is the problem which doesn’t exist in er 301 because Brian has done very customer friendly solution in the structure.

Merry christmas fo everyone! Thanks for Kel, your posts has helped alot, hope this forum don’t get toxic anymore and you come back at some point!




I don’t speak up much here, but wanted to give my opinion. The 301 has quickly become the most used module in my rack. I seldom, if ever, run into CPU constraints.

That said, I find the idea of a future upgrade really exciting and I hope that the work that O|D put into making it possible was not in vain.


I’m also trying to figure out where this took such a strange and disappointing turn, whereas I felt it was more of a reason for great excitement.

I have multiple PCs that run Windows. They each have different processors. I spent a little more on the one that I planned use for audio and video editing than the one that I planned to use mostly for email and web. But when there’s a Windows upgrade, they all get the new OS features, and really, they both meet the minimum specs for whatever 3rd party software I want to load on them. The more expensive one can run more concurrent apps before it starts to slow down.

Isn’t this kind of the same thing?

My read on this was that when you released a new firmware, you’d be compiling it twice, once for each processor. Not that an ER-301 with the AM3352 would be forever locked to a particular firmware version and never get new features. Is this wrong? Because if not, I am just not seeing the downside to an optional upgrade from a consumer perspective other than maybe confusion about it.

Edit: For what it’s worth, I also thought offering two models was a pretty interesting idea. Someone who wants to use it as programmable sampler could easily get by with the AM3352 version, and save some money. Someone who wants to use it as a custom 6 operator FM synth with custom effects might want the upgraded model.


I believe having the ability to use an upgraded CPU is a wonderful feature, especially considering that other eurorack manufactures would often just require you to buy a whole new unit. The fact that there is the possibility of a CPU upgrade is a wonderful selling point of the ER-301, in my opinion, because it means that the unit can continue to grow in power over time as processors continue to become more powerful.

I hope that the tone of the discussion here hasn’t dissuaded you from continuing to do the great work that you do - the fact that you are so communicative with the ER-301 user community and so responsive to feature requests, and so thoughtful about your design choices while continuing to have open dialogue is a very special thing, which is one reason I think people were so quick to jump to your defense - hopefully the tone was just misattributed to cultural differences or the difficulties inherent in textual communication as far as the lack of non-verbal cues.

I was sad to see the harsh criticism that Olivier Gillet received sometimes and how it seemed to change the direction of his adding additional features to his modules, and that made me very sad because to me, one of the big points of his modules were that they were so feature rich.

We should be kind to the creators around us and to each other, I think… This community is very special and it is worth nurturing and protecting.


Sorry to hear that Brian is discouraged about the possible release of a unit with an upgraded CPU. I hope my question about timing didn’t contribute to that shift.

As someone who has 30 HP of a limited 7u rack earmarked for the ER-301, I’m merely interested in knowing my options, since this is a substantial purchase. I agree overall that it’s a tricky combination to develop a product that combines beta releases/firmware upgrades/open community engagement. However these elements are definitely part of the appeal to a potential new user yet it becomes hazy to decide when exactly to take the plunge. Regardless, the openness and experimentation of Brian and this community is what separates this space of audio-technology production from others. No one should shy away from that or feel the need to apologize.


Thank you everyone for the supportive vibes :star_struck: I’m not in a funk or anything (well actually I am but that is because the frame of my very beloved bicycle of 10 years just snapped today as I was blowing off some steam on a hill, grrr!).

Please note: The drop-in upgrade will definitely happen. I’m just not going to start working on it until we get to firmware v1.0 with the current hardware. What does firmware v1.0 mean? Well roughly it means the SDK is live and kicking, all of the major parts of the UI and the bread-and-butter units are implemented and fully documented.


The ER-301 is a fantastic module as it is already. The firmware is constantly changing. I find Brian’s job fabulous. By buying the 301 I knew exactly what I was going to receive. Now that I have spent many hours with the 301 I am (as for the 101/102) more than happy to have made this choice.

Sincerely, stop whining for an upgrade or have the 301 make you coffee in the morning and iron your shirts …

And if you need more power, buy a second one. That’s all :stuck_out_tongue:


That sucks, what kind of bike was it? :grin:


A no frills touring bike with a custom Cherubim steel frame that I bought used and built up from there. :cry: I guess I should have been more careful about inspecting it for small cracks. I used it for everything. I often strapped module shipments to the rear and front carriers of this bicycle to take to the post office. :sweat_smile:


I also want to contribute and say that I was/am an early adopter of the er-301, and in ALL my use I have never ran out of CPU.


Uff, my condolences, those are nice bikes. I feel your loss. Steel frame though, could you get it welded?

I have a steel frame Trek fixed gear that I ride everywhere, though the first big snowfall in Toronto just landed, so that’s that for the next 4-5 months. Sigh.

As if I wasn’t impressed with your operation already, the vision of you delivering modules on a bike to the post office brings a smile to my face.