Hi everyone,
This is my first message here. I am beginning to build a synth. I think I will try to mostly follow the Kosmo specifications.
But I hesitate between 4 way molex terminal headers (or maybe 5 because I would like to have 3.3 and 5V too), and eurorack compatible connectors for the power supply. Fancy connector with every voltage I want, or eurorack + voltage regulator on each module when i need 5V ?
Maybe eurorack is easier to find, more “standard” between different stores online ?
I would like to know why Sam used molex before (as mentioned in his zine n°6), and eurorack now ??
I think it is better to use a known standard. You can then easily use other people PCB’s. Maybe in the future you decide on buying some commercial modules. Most designs tend to add 5V regulator on the module.
And consider that such a connector with all the values will take up more space, even if you don’t need it on a module.
Very few Eurorack modules actually use +5 V, and few of Sam’s do too. Those that do, like the 1222 VCO, use a 5 V regulator connected to the +12 V rail. If you plan on making a lot of use of microcontrollers etc. that need 5 V or 3.3 V, you might want to choose differently.
I don’t know why Sam went with the Eurorack style ribbon cables for power. It’s good because you can leverage Eurorack designs and equipment, not just bus boards but module circuit boards; you can fairly easily adapt DIY Eurorack modules into Kosmo format. On the other hand it’s widely agreed that ribbon cables are not the best choice for power distribution. Fewer larger conductors makes more sense. The MOTM and Frac Rack formats use 4-pin MTA-156 connectors for ±15 V and two ground wires (ground has to carry as much current as both voltages), as do some 5U formats, while others use a 6 pin MTA-100 for ±15 V and +5 V.
It’s your choice. Use what appeals to you, and is technically suitable. Eurorack will give you lots of compatibility options, others may perform better and give you access to more voltages. Nothing seriously wrong with either.
ok thank you for your answers, I think i will choose eurorack connectors.
But on thonk, the 10 pin cables are labeled “NOT POWER” ? I don’t understand why ?
Do power supplies always use 16 pin output, and we have to use a 16 to 10 if we only use 10 pins ?