DIY Eurorack Case Part 2: Power Supply

[@bobmichelle]

Planning my first case here... that helped a lot thanks ! This DIY power supply build is way cheaper than classic power modules, I like that :)

[@michaelprado9259]

Thanks for composing this video! I followed your guide and BOM to finally build in some decent power to my home-made cabinet. Goodbye inadequate flying bus!

[@ozerik]

Hey.... your comment disappeared from my video hmmmm... The output of that reverb needs to be amplified, which is taken care of with the output mixers. The wet/dry levels *should* be about equal but it's easy to mess that up -- one of my My Favorite Reverb modules has the wet level louder than the dry. Can be cool while performing -- keep the signal dry dry dry then twist the knob to dump some signal into the reverb and "BWAAAaaaahhhhhh" that reverb signal lives in the output till it fades :D By the way, GREAT case, great production on this vid -- glad to find another synth DIY person!

[@heyudude]

Enjoyed this build of the basic PSU, thanks. The outro was super 😀

[@MChristian]

This is such a clear and informative walk through. Thank you!

[@mikegeary8056]

Piston Honda mk-1! My favorite

[@soejrd24978]

I just got my PSU in the mail today lol (think it's the same one). I'm building my case too this week. 126HP 9U, total is about €75,-

[@extralifedisco]

Nice timing. That'll be a monster case! Good luck with the install

[@Karedu.]

@@extralifedisco what is the voltage/ampers of that psu?

[@extralifedisco]

@@Karedu. 50W - 5V/4A 12V/2A -12V/0.5A (The 65W version is common as well - 2.8A on +12v)

[@channelite]

Thanks for this informative video.

[@julians7785]

great content!

[@sasemoimusic]

Thanks for this detailed and clear explanation! I'm about to embark on a DIY case journey and everything is pointing in the direction of a Meanwell power supply, however one thing I don't see anyone who's using a Meanwell mention is that the -12V comes at a maximum of 500mA / 0.5A , according to my ModularGrid case sketch I would draw 750mA (+ headroom) on the -12V side, I've sketched a 7U 104HP case. What are your thoughts on this, do you know how much your cause would draw on -12V and if that's all going well? Cheers!

[@extralifedisco]

Interesting, I don't use modulargrid that much so I don't know exact figures, but my case would probably be 300-400mA on the -12V rail. Eurorack modules don't tend to draw a lot of negative voltage, it's really just for balancing op-amps, so I'm guessing you have a lot more modules in your case. I use one Meanwell RT-65B for each row of my 84hp case. They can do more, but separating analog and digital modules gives me much better noise floors. I would recommend using at least two power supplies for your case.

[@sasemoimusic]

@@extralifedisco Good points! One PSU per row is definitely the safe option. I've noticed it's the pure analog modules that draw the most -12V , I'll have a look into separating them their own rows and perhaps use a Doepfer LC3 to provide for the heavy drawers! Good insight, thank you :)

[@jovinl283]

thanks

[@3rdman7thson]

How many milliamperes will that power supply put out?

[@_else]

Thanks for making this video. I wired up my case today, checked the voltage...everything looked good until I plugged in a module and it started smoking? I used 12 gauge wire. Do you think that might have been the problem?

[@extralifedisco]

12 gauge sounds, if anything, oversized for +/-12V. I don't think that would be the problem. Most likely you have reverse polarity somewhere - I had the same thing happen when I connected a mixer module backwards (it had an unshrouded 10 pin connector). Make careful note of the "red stripe" and -12V orientation on the eurorack module and double check that your busboard has -12V in the same place .

[@_else]

thanks for your response! i realized it was the ribbon i was using--nothing to do with the case. it works great!@@extralifedisco

[@austinindierecords]

How did you screw down the modules to the wood?

[@extralifedisco]

With small screws, they are size #4 x 3/8 24 TPI pan head sheet metal screws

[@harrisonallen]

Sorry for the late comment! Curious though, I’m making my first case following this, and in the video you say you got a 10amp fuse for the power switch, but the link in the description is for a 5amp fuse. And the data sheet for the switch says it runs 6amps. So is a 5amp fuse ok?

[@extralifedisco]

5A*120V= 600 watts. These power supplies draw only 65 watts so a 5A fuse should be plenty large for this application, though inrush current will be higher, it shouldn't trip a slo-blo fuse.

[@harrisonallen]

thanks!

[@woosix7735]

nice.

[@nyrbsamoht]

man your videos are perfection. I followed your advice for building faceplates (from your passive mult video) - and now i have about 5 nice fully diy modules (mostly MFOS modules) now i need more power I got a meanwell rt-65-B 2:05 one question - do I really need a Power Entry Module with an EMI filter? locally I can get IEC320 fused switches cheaply everywhere - but switched fused emi filtered ones are much harder to come by. could I get away without it? meanwell supplies are already supposed to be potentially noisy - i dont want mine extra noisey...

[@extralifedisco]

Excellent, glad to have helped on your journey! Good question about the EMI filter on the entry module. It's probably a little above my pay grade, but I don't think the filtering will have much effect on the noise in your eurorack system itself. It will probably prevent the PSU's high-frequency switching noise from being conducted back to the wall outlet through the power cable - so more likely that kind of noise would end up as RF emissions audible through other devices (e.g. a guitar with single coil pickups). It's definitely not required, so I would use what you can get your hands on and then if you notice that the synth being on causes noise somewhere in your signal chain, consider adding filtering (you can also install a discrete EMI filter inline inside the case rather than swapping the entry module).

[@nyrbsamoht]

@@extralifedisco good idea - I can get discrete emi filters from my local radioshack (Jaycar) no problems. thanks for explaining that makes sense enough to me. If i notice some RF noises coming from my setup while my Eurorack is on ill look into it. but in the meantime - I got a cheap one off ebay (with fancy led switch) which will be here soon - and i can finally finish my case - a significant upgrade from my cardboard shoe box skiff :S thanks again and I look forward to the next one :)

[@tubeDude48]

Just a tickle at 120VAC At 1:39, that power supply would be cheaper on Amazon! Mounting a Module ABOVE the power Sup. will produce LOTS of noise on that module!! --- Proper US Color code would be GREEN, NOT Yellow! Should find-out what the total current is and adjust the Fuse size accordingly!

[@extralifedisco]

Green would be good! I'm used to Romex with black/white/bare for L/N/G but I didn't realize there's a separate red black green standard. Good point on the module noise, I've tried to keep the analog stuff in my cases far from the PSUs in general but that's mostly because they're to big to fit on top lol

[@hintoninstruments2369]

There isn't a red black green mains standard any more (there was in the UK once). The US standard is black, white, green, elsewhere it is brown, blue, green&yellow. People expect to see these colours and understand what they mean. If you use non standard colours it creates confusion and you may make a mistake when you change something.

[@tubeDude48]

@@hintoninstruments2369 - And your telling this, why? Yes I know the Standard in the US.

[@ArkaHtun]

I’m a bit confused . The performance at the end showed you switching on two switches to power it up didn’t show them when wiring up ,

[@extralifedisco]

Yes, I added in a front panel module to allow each busboard to be turned on separately. Each panel switch is just an SPDT that toggles on the +12V line from the PSU to one busboard. This is not often necessary but I was having issues with some older digital modules not booting properly when other modules were plugged in so wanted to separate them.

[@ArkaHtun]

@@extralifedisco thanks for that explanation .. I’m just about to build my first diy case , hmm I’m might look into this as a solution , modular grid has calculated my modules power needs , and I’m getting a bit close to the top limit of the meanwell RT65B ,, I. Planning on running 12u at 101 hp .. if switching them all on at the same time causes issues .. fingers crossed ..

[@jobbe-wijnen]

the order of phase and ground on mains is not so important (when in US and Europe, not UK) because wall socket plugs can be rotated 180 by users, whicj effectively switches 'polarity' 😊

[@hi-ccowboy7983]

Are you referring to two-prong plugs? Those shouldn’t be used and, if for some reason they are, the hotwire has a wider spade than the neutral. Unless your repurposing some very old cables that shouldn’t be an issue.

[@hintoninstruments2369]

This should be called How NOT to wire a Eurorack case and How to get a Darwin Award. The IEC Inlet should not be on the outside of a wooden case, it is asking to get broken and then you will have exposed live parts. A better way is to mount it on a small metal plate and mount that on the inside so that the inlet is recessed. There are proper rubber boots to go over the back of inlets and insulate everything, get them from the same source. Using electrical tape is tacky and will eventually come off as the adhesive goes soft or dry. Why is the inlet the opposite side of the case from the PSUs? It should be next to them. Use the proper standard colours. A 10A fuse is far too large. Work out the maximum wattage and divide by your mains voltage to get the mains current. Your crimping bodge is a terrible idea. Use the proper tool, they are only $20, to wrap the connector around both the stripped wire and the insulation. Look at the die there are two diameters, this holds the cable so that strands don't break off one by one with flexing. The GND terminal on the PSU is a frame ground and only connected to the cover, there may be a capacitor to COM. You need to connect the mains Ground to the 0V of each busboard. The mains terminals of the PSU should be covered and it would be better to use insulated ring terminals. If you are still alive and want to stay that way take these criticism seriously.

[@extralifedisco]

Thanks for the feedback. The inlet is quite robustly attached, I would use metal sub plates only if the case wall was thinner. The electrical tape I agree is a temporary solution. On my newer case I used longer disconnects . I did want to put the inlet on the same side as the PSU but could not fit them all near each other with crowding out space for the bus boards or usable module space, so elected to run the wires across which I agree is suboptimal but a deliberate compromise. The live DC terminals were covered later by a 3d printed part on the PSU. I have not found the mean well factory terminal covers reliable or effective. Ring or fork terminals would be better for attachment but I have not had any problems with slippage or work hardening as all wires are staked down and secured. Fuse rating suggestion is well taken, a 1A or 0.5A fuse would be more appropriate.

[@technodruid]

Switch mode is way too noisy. Hope you don't have any sensitive digital modules

[@bigggmoustache8868]

What's switch mode?

[@extralifedisco]

Switch mode power supply is when a higher voltage is quickly switched on and off (with transistors or switching regulators) to create an AC wave and then filtered through capacitors to create a lower voltage DC supply. This is as opposed to a linear supply, which takes a rectified AC input and dissipates excess voltage as heat. A switchmode supply is smaller and more efficient but a linear supply is quieter and more accurate, which for some sensitive electronics is important to performance.