I’m very new to DIY electronics and have only been doing very basic stuff so far, but I’m very inspired to try some of LMNC’s Kosmo Modules!
I’d like to use them as stand-alone modules, similar to guitar pedals (to be independently moveable and not in a fixed rack). I hadn’t thought much about power supply as I naively assumed the modules would need +12v or +9v, also similar to guitar pedals.
I have now realised they run on the eurorack standard, as I understand to be +12v, -12v and GND. Since I’m new to electronics, the +12v and -12v is very confusing to me and I have trouble understanding what the best solution is.
I have read from other forums and seen from LMNC that the Frequency Central Microbus is a preferred way to power the modules. But from what I understand, this format is to power multiple modules in a rack.
Is there anyway to power these circuits more like guitar pedals, where each own module gets its own power supply and you therefore can build them into independent boxes?
Hi and welcome!
There is nothing to stop you building individual units, each with their own power like many guitar effects.
In modular systems using a single power supply for a number of modules is an economic and efficient way to grow a system.
Why a bi-polar supply? (+12/-12)
Many of the standard components used in modular need a bi-polar supply to operate.
Many don’t and use just the +ve and ground as a DC source.
Have a look at lunetta systems or cusi sounds,(on YouTube) 'little boxes’series for 9v based DC projects.
Search here too as many members have produced excellent stand alone projects.
Some guitar FX require 18 to 24 volts DC , some take that and convert the total to a 9 or 12 volt bipolar supply as their components require.
Most important is to pick a project and just make it then decide on what next based on your own experience. All of us here have stood where you are now and we’re all on the same journey.
Now go find a fun project and crack on!
This is an option too if you want to get your own circuit boards made - and it sounds like you may want a fair number, this one would be an inexpensive option.
from our very own @analogoutput - pretty similar to the frequency central ones, adapted for Kosmo format - no 5v, 10 pin power instead of 16 pin.
You will need 12v AC wallwarts for either of these options.
Any of these would be, I think, significant overkill for powering a single module. FC Power supplies 500 mA on each rail. For comparison the average current draw for modules I’ve built is about 21 mA +12 V and 14 mA -12 V, so you in theory can run about 24 modules on one supply. (In reality somewhat less.)
I’m not sure what the appeal of a PSU-per-module setup would be. Modular synthesis is not like guitar pedals where one thing does a useful thing on its own — an oscillator on its own isn’t very useful, a VCA likewise, nor an envelope generator, and so on — you need to put about half a dozen or more modules together before you get anything that starts to be usable. And they’d all have to be plugged into a wall power strip anyway (unless they’re all running on batteries and then you have a whole lot of batteries to maintain). Seems just as easy and a lot cheaper and less fuss to plug them all into a single ±12 V power supply. They could still be in separate boxes, if you wanted that.
Hmm. Interesting. They sell the Eletechsup DD1718pa module it’s based on for £10 but at https://eletechsups.com they sell it at $2.31. Quite a lot cheaper than say the Mean Well DCWN06A-12 I used in the MI Module Tester ($10.64 at Mouser). There’s not much information about it, though, I see no datasheet. FC says “Speak Truth To Power regulates down to +/-12V DC and will supply +12V at 600mA and -12V at 200mA” but Eletechsup says “Maximum output current : +Vo is 600mA,-Vo is 120mA”. Seems a significant discrepancy. Either way, it supplies a good deal less current on the negative rail. As noted above, analog synth modules tend to use + and - voltage at about a 3:2 ratio, so such an unbalanced supply is not a great match.
And I don’t see any information on ripple, line regulation, or load regulation, just “Deviation is ±4%”, whatever that means. Altogether seems a rather sketchy thing to base a synth power supply on.
… and that runs from a decent USB C charger with PD support (although it would work with any old charger). These boards can negotiate up to 20V at 5A for you, although it will only get what the charger is capable of providing, obviously.
I’ve got two power supplies that I’ve made like this (and a third one based on just the buck converter part) and they’ve been really good. I’m just about to order the bits to make another, funnily enough!
first of all, thank you so much for your replies!!
this whole diy electronics thing is definitely one of the steeper learning curves I’ve been on but it really helps with a very helpful community, so thank you all!
It definitely seems more economic and efficient to power multiple modules in a rack with a bus power supply…
The reason why I wanted to have the modules in individual cases (which I probably should have specified in my original post) was to use the modules as an outboard effect for mixing as well, and not only in modular synthesis.
Some of modules that I’m really interested in are ’ The Triple Splashback’ as ‘The Safety Valve’. And I would like to be able to use them as independently and freely as possible.
Say, I’m going away to record some music and I would like to bring ‘the safety valve’ as an effect to use. Then I wouldn’t want to bring my whole rack but only the effect.
Maybe this is not exactly the right format, since it’s made to be in a rack with other modules but I was just thinking if there was a way to do it…
so … make a small case? You can always swap modules out. That’s we we all do. Your use case seems like it would also dictate that you don’t ever really own many modules, so a small rack to house 3 or maybe 4 effects and maybe an output/mixer module doesn’t seem like too far a stretch and is more flexible.
There definitely are some modules that do something you might like to do to a non-modular signal, mainly effects of the kind you mention.
One thing to bear in mind is that synth modules are designed to operate with higher level audio signals than you typically find from, say, guitars or line level outputs. So there exist things like the CGS Stomp Box Adapter, which is a synth module that can boost external signals to synth levels and attenuate synth level signals to levels suitable for external equipment. You’d probably need something like this in addition to the effect module.
Additionally, some of these effect modules take control voltages to modulate their effects, and if you want to do that, of course you need other modules generating those control voltages.
So even in this case you’d probably want at least two modules and maybe three or more to accomplish what you want to do.
They could be installed in a small case with its own small power supply. Doesn’t have to be a big system. You could move modules back and forth between a large modular system and a little effects case.
Or, if there were some effect module you expect to use only for processing external signals, you could build it into a case that includes it, a level adapter, maybe an LFO or other control voltage source if appropriate, and a power supply, and keep it as a dedicated thing separate from a modular system.
