The reason 10 pins are used to carry only three voltage rails is to enable them to carry more current. If you’re using only one wire per rail, use heavier gauge than ribbon cable.
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I have the components so why not give a try : ) But good to notice, I did not thought about power consumption.
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I wondered this but never asked. I just kinda did it and it works so I figured sure I’ll keep doing what works. Makes sense though.
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I had no idea that Ac adaptors existed! this is a relief… Anyway, can anyone point me toward a good one (12V is probably best)? It seems the only one listed in this thread has given people issues in the past.
Sorry I don’t have one in particular to advise you, but to look for one and if you plan to build Sam’s modules, yes it’s better 12V AC/AC (and 2 or 3 Amp that’s good)
you will also need to transform and regulate the current something like that for example
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Another question about this topic - with a 12v AC/AC adaptor, how do you get ground (0v) from this? Just with a voltage divider or do I need to do something like a virtual ground setup? I think generally op amp circuits require both + and - voltages as well as some reference voltage. Even more, if I have some other chip in my circuit that doesn’t require -V then I will likely need +V and 0v. I have not had good experience with virtual grounds in the past because they are never stable if you have a load somewhere else in the circuit, so I’m hoping there is some other way
One of the AC lines are used as 0 V, the +12 V and −12 V rails are regulated against that one.
(This means that you have to be a bit careful if you connect multiple supplies to the same wall wart; see this thread for a bit more on that.)
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Thanks. Can you explain this to me? I get that with red and black coming off the wall wart, black can be ground and red swings between +/-12v. (correct?) But what circuit do I need to isolate the + and - voltages? A rectifier? Thanks for all your help, I am pretty new to this.
Please get the microbus found in the threads listed above. It solves your problem for you by splitting the voltages and if you are asking these questions, it might do so better and arguably more safe than whatever else you come up with. (not a dis)
Power supplies arnt what you want to be your first ground up DIY project. You can build the microbus kit, but i mean coming up with your own power supply isnt just ambitious, it could be dangerous depending on your skill level.
Its not expensive, and it will give you a good power supply that will treat you well.
Seriously, dont ignore this. I cant tell from your post what you are planning to do with your wallwart.
I dont mean to scare you, the walwart will condition the power to safe(er) levels, i just cant be certain what you would do, and would rather err on the side of not having someone fry themselves.
I am someone always looking to get by with as cheap as possible components etc, but you dont go cheap with this. Even ignoring the safety, dirty power can ruin your creations or just flat out not work.
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Totally hear ya. I will say this isn’t my first project, but I understand your concern, and I appreciate it. I guess I just wonder how there are things out there with op amps in them that just plug into the wall without needing a bus like this?
I guess I should add that I don’t actually want to mess with 120V power anyway, but +/-12V from a wall wart I would consider messing with
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Anyone ever built one of these?
$4 for not just the board but the full kit!? Obviously this isn’t going to be the PS of choice for a large synth but for small portable synths or for testing new modules it might be good.
Also this:
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Haven’t built it, but I did notice it. Kristian Blåsol’s stuff kinda redefines cheap.
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There are many ways to design and power circuits, but people here will generally point you to solutions that known to work well for the kind of modular stuff (Eurorack, Kosmo, …) most of us are building. Using the same standards as everyone else makes it a lot easier to mix and match designs, and also to get help when something doesn’t work.
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It’s a basic 78xx/79xx datasheet design, with somewhat limited smoothing caps (470 uF – didn’t he run into problems with that later?), limited room for heatsinks, and no protection diodes, but if you’re fine with that there’s nothing wrong with it 
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I used 2x2.4A 12V AC/DC power supplies, 7805 with heatsink and 100uF for the +12v line,100uf for the -12v line and 100uf with 100nf for 5v line as I remember. All costed me less than one pound (really, powerful and stabilized power supplies 0,3 pounds each). For making “power delivery tapes” i used single core copper strip-cables - they are often used to mount LED tapes, so 4 cables in one tape, paid 2 pounds for 10m of stripe. Need to glue them properly, but seems to work fine.
2 pin connector for the cable and on/off switch on the back.
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I’ve got the basic Frequency Central power supply, with more on the way… How many modules should that be able to power? I realized things were not sounding right, so I unplugged modules till I got down to LFO, VCO x 3, and Filter till it seemed normal. How would I test when I have reached its limits?
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it depends a lot on your wallwart power supply 1A, 2A or 3A?
2/3 is good,
after if you have enough amps you can put about ten modules per FC (it depends on the modules, some consumes more than others)
the best would be to know how much exactly consumes each module, when you buy ready-made it is often indicated, but with DIY modules …
even if it is always possible with a small assembly to calculate their consumption it is more complicated.
So it’s better to look a little wider for your power supply to be sure.
I have 2 FC in parallel on each 2.5A wallwart
but apparently you must have missed a little power (A), but some here can explain to you in more detail than that I think 
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Thanks Dud. I currently have several 1 amp adapters, probably because that is what frequency central says on their build document, Looks like I can get up to a 2 amp one here.
Found another mention of the 2 amp being used here:
us 2000ma adapter
https://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&pa=2197581&productId=2197581
https://www.amazon.com/gp/product/B00R5CEDRM/ref=ox_sc_act_title_1?smid=A3O3SSGGJLKX15&psc=1
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some info about that review this vid of Sam (power supply at : 6.05’)
and his fanzine 6 :
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