Hello,
I am a beginner in modular and even more of a noob in DIY stuff, seing LMNC’s videos got me motivated to try and build my own CEM 3340 VCO. I bought all the necessary components but before I start soldering everything together, I would like to understand how to power it up, I don’t want to buy a complete bus board and power supply as I only want to build and play around with this oscillator (for the moment). I looked at the FC power by frequency central but I don’t understand how I would plug the oscillator into it (it’s probably very basic but I’m new to all of this : ) )
Thanks for dealing with me,
Have a great day
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The FC Power is a good choice to start, and it’s capable of powering a whole row of modules before it runs out of steam.
To go with the FC Power you’ll need an AC to AC wall wart. To connect your module to FC Power you’ll need a Eurorack ribbon cable.
See this old video by Sam Battle showing how he does it. He talks about powering the synth case at about 6’50".
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The FC Power has a single 16 pin box header. You can use a standard Eurorack power cable, which is a 10 conductor ribbon cable with a 10 pin IDC connector on one and and a 16 pin IDC connector on the other; plug the latter into the FC Power and the former into the VCO. (You didn’t say which layout you’re looking at, sometimes they include a Eurorack style power header and sometimes they don’t, but it’s fairly simple to add one.) Cables can be bought from various sources, or you can buy ribbon cable and connectors and assemble your own pretty easily.
Alternatively you can install a terminal block (2.5 mm or 0.1" pin spacing) on the FC Power and either put another on the VCO and connect them with wires, or just solder wires to the VCO for power and then screw them into the terminal block on the FC Power.
Or you could dispense with the terminal blocks at both ends and just solder wires, but then the FC Power would be more or less permanently dedicated to powering a single module, which would be silly.
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Thank you both so much for the amazingly quick answers, I actually went for the FC power from Sam’s DIY case build. I was missing the ribbon cable to connect the oscillator to the FC Power, I think I’m gonna go with the simple ribbon directly from one into the other,
If I can ask another question, how does the soldering of the connector on the stripboard work ? I’m using this model btw
I’m sorry for being such a noob, but I really want to make it into this DIY world !
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That stripboard design doesn’t include a Eurorack connector. You may find it more convenient simply to take three wires from the FC Power’s +12V, Ground (GND) and -12V outputs to the points labelled at bottom right of the stripboard. They are those three lines coloured red, black and blue going right away from the border of the stripboard.
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I will most definitely do that ! Thank you for dealing with my questions,
Have a great day / night
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It’s a great choice of circuit to start with. Have fun.
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This is a different circuit but similar ideas apply
Or as said above you can use a terminal block instead like this:
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Could I solder wires directly from the VCO into the +12V -12V and ground of the FC Power or do I need to use a terminal block ?
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You can solder them directly but if you use a terminal block it will be easier to disconnect one item and add another. It just reduces to turning the screws instead of desoldering.
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In this case would it be wiser to use another stripboard as an adapter as @analogoutput suggested ? It seems pretty doable and I got spare stripboard. The FC power is pretty costy for my student budget, I wouldn’t want to ruin it.
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In case you’re wondering, Analogue Output is the expert on this. I’m just another newbie trying to help out.
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haha you’ve been of great help !
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Yo, I’m also a noob, also on student budget - personally I’d suggest committing to building the FC power supply to spec! with a box header and maybe an adapter like suggested. You’ll undoubtedly want to use the supply for some other stuff down the line and if you conform to the standards it’ll make your life a lot easier. Sadly one part of being on a tight student budget is planning to be as flexible down the line so you don’t have to spend more money fixing mistakes
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The terminal block wouldn’t ruin anything, it’d just be a different way to connect to the FC Power.
I don’t think I suggested a separate stripboard anywhere, maybe you’re thinking of @fredrik’s post here. You could certainly do that if you want to go the ribbon cable route, but you also could just put a box header right on the VCO stripboard. And I found another discussion of how to do that with exactly the same stripboard you’re building.
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The great thing about standards is there’s so many to choose from. Kosmo uses 10 pin ribbon cables, adopted from Eurorack, but you can argue ribbon cables are a poor way to distribute power compared to single stranded wires for each rail which is what most other synth formats use. I’m sticking with Kosmo and Eurorack standards myself, but that’s not the way you have to go.
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Sorry I messed up who wrote what on the other post, what would you reckon is the best solution for me ? Oh ok I think I just understood how the box header would work, the ground would occupy the 3 middle spaces of the box header, so its exactly like making a separate adaptor but on the VCO circuit itself right ?
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On the layout you posted, it’s pretty easy to add a header without fudging.
Leave the +12V row as it.
Put three GND rows, and connect them together with short jumpers.
Then put the -12V row, and lenghten the left short blue jumper to reach it.
Solder the header instead of the three wires on the right.
Also, if this is your first project, remember the copper stripes go on the BOTTOM, even if they are shown on top in the pictures.
[Edit: added shrouded connector and red stripe]
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Thank you very much for that, I think I’m going to use the model you just sent with the header, do you have any recommendations for the 10 pin header (where to buy it) ?
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Search for 10 pin or 2x5 pin shrouded or keyed headers on Amazon.
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