Bananifying Eurorack Modules

Hello everybody!

I’ve been thinking about converting some eurorack modules to bananas for a while now. A couple of days ago, with a module that I don’t use too much, I cut one of the pins of the Thonkicons that carries the ground and through the plug of the minijack I inserted a banana cable. At first they are a bit hard, but they enter without problems … The fact is that in this simple way I think that the input could be converted to banana mode, leaving a common ground connection to connect the rest of the devices. My Lorre Mill Double Knot recieved the signal without any problem, so with this module it worked!

As I don’t have much idea about electricity, do you think this solution could be valid? The good thing is that it would allow the modules to be reconverted back to eurorack in the future by changing the connectors, but not having to make major modifications.

I await comments in case somehow I end up burning something … :slight_smile:

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First thing i think of is that befaco started out that way. Maybe good to look into their old modules.

Second thing i think of: take care of modules which really heavy on normalizations for context mosy mutable modules and the run jack on just friends. I do think it can work on some modules but not on all.

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There are really 2 things to be aware of:

  1. Voltage range: some eurorack modules may have different expected or outputted voltage ranges vs banana synths, especially negative voltages (e.g I think some Lorre mill synths don’t like negative voltages).
  2. Grounding: every 3.5mm connection bridges the ground between the connected devices: this isn’t true of banana jacks. Assuming the voltage is acceptable, you can connect the tip of a eurorack module connection to a banana jack port, if there is at least one connection between the ground of the eurorack modules power bus and the banana synths. Banana synths often have a ground port, so if you connect that to ground of the power bus of the module, you should be good.

On the subject of ground, I wonder if there is 2HP module that is just one banana jack connected to ground for the bus? This could be used to bridge ground, along with passive 3.5mm TS to banana adapters (which connect the banana to the tip).

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I actually have a format jumbler, but I’m not using it because I’m connecting all audio outputs from both eurorack and banana synths to the same audio mixer, so the ground is already there I guess …

I know the problem with voltage ranges and negative values. My idea is just use several modules to do this conversion. For example, Pressure Points, Teletype, the TXo, and a few more … I think all of those modules work in a positive range of voltages …

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TXo covers -10…+10V range, so you’ll have to be careful if using it with something that doesn’t like negative voltage (you can use TO.CV.OFF and TO.OSC.RECT ops to shift LFOs into the positive only range).

Oh! That’s a great tip! Didn’t know about those 2 TT ops … So by using a rectified Oscillator from the TXo I could use it to FM the Lorre Mill DK with only positive values, right?

depending on the rectify setting yeah, you can get it to send only positive voltage by either clamping or inverting negative values.

Finally I managed to convert the Teletype and TXo to banana cables. The good thing is that they still work with normal eurorack cables, so the question is, for what is the ground connection on the Thonkycons needed?

Anyway, the big problem was that as most of the eurorack modules have an aluminium faceplate the current is shared to all the cables connected, so I purchased several T-shape nylon rings from Mouser o avoid the jacks and the nuts touch the faceplate. Now each jack is isolated from the rest and the system is working …

I will try a few more modules, like the Pressure Points and a VCA …

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really depends on what you are aiming to do. I would say the converting existing modules is a huge work and if you don’t really know what you are doing you may accidentally damage something very expencive. Why not just buy modules already in this format? There are plenty of options from buchla or serge (or from many of these derivates) systems as already discussed in this earlier thread.
One comment about you picture: make sure to establish a ground connection between two systems when cross-patching systems like this.

I would absolutely love to see more solutions here from Low-Gain Electronics

Its been awhile since I’ve visited his site and there seems to be some new solid things he’s done! But if it was me personally Id look into a solution as to where you convert the CV rather than the module itself.

Shit, at the same time if your are planning to lots of conversion boxes you will have an absolute rats nest before ever playing a note! :sweat_smile:

I’m wondering what you mean by this: do you mean that you can plug a 3.5mm TS cable into the banana port and connect it to another eurorack module and a usable/reliable connection is made?

What I mean is that you can actually connect banana cables between converted euro modules or TS 3.5 cables. For example, in the attached image I’m sending a BPM trigger from the TO.TR 1 into the TT input 8 to divide the pulses with a banana cable, but I can also use a TS 3.5 cable … The result is the same …

My main purpose is not to convert all my euro modules but just a few of them. I have a case with a full set of Random*Source euro modules. I probably should have taken the banana way earlier, but anyway, I’m pretty happy with them. I use this set to record sounds and use them in live performances with or without the Serge system itself. A few weeks ago I purchased a Lorre Mill DK, and I’m very happy with it, so I guess I’ve started the banana pathway … The thing is that being able to use other euro modules with banana systems without a format jumbler is very tempting, so I’ve started with Teletype and the TXo (right now I’ve finished the Tallin too …), and tomorrow I will convert a Radio Music and the Pressure Points.

Changing my setup is not in my plans. I’m happy with the system and also in pure banana systems there are limitations too (no sample players, for example), but being able to trigger sequences, samples or control pitch sequences from TT to the DK is fantastic for me.

Yes! In the picture there’s a banana going to one side of the small euro box where the ground is shared by the 2 systems. If this cable is not connected, it simply doesn’t work …

My only suggestion would be to do little research about the modules you plan to convert beforehand to see if there already is 4U/banana alternative for these. I know that there exists (unofficial) 4U versions of some Mutable Instruments and also Music Thing Modular (and some others) so it’s maybe worth to check. Also, as mentioned by @chalkwalk and others - be careful with polarity while patching CV from eurorack to Lorre Mill (or buchla or serge). Other way round should be safe.

I considered doing this as I had about half a setup in banana and half in euro. I then bought a Coco and just pretty much got rid of almost everything in euro and found substitutes in banana. Honestly some things I didn’t find substitutes for like Pressure Points I don’t really miss actually.

What I did before the switch, was just make a bunch if cables that go from euro to banana. It was helpful but tbh banana to banana is my favorite.

Youtube just recomended me this video and i thought of this thread:

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Wow! If I have time some day I could do a proper mod, but for now I’m not going to touch my euro Serge modules … :slight_smile:

not sure how much resale value these modules will have after a permanent mod like this. All the R*S serge modules are available in a convenient 4U banana format in their website.

Love this but wouldn’t the banana jacks short with the ground plane?

I’ve done a load of mine. I chose to only do pieces that had no normaling and socket/pcb configurations that were conducive to the switch. In most cases it’s a doddle, you can do a few in an hour.
I missed the normaling on one piece but can get around it by remembering to leave that socket patched. If there’s space you could fit a switch?
It might have lowered the resale value of them but I like them better this way.
As suggested above, in the time that it took you to banana a module you could make some ts->banana adapter cables which would work as well.

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