Single powering options for multiple devices

Elektron Gear
#82

I’ve had similar ideas to what is being discussed here in this thread, for being able to power MacBook Air, Push 2 and one or two other devices.

I like the idea of having a USB-C charger with multiple outputs and then using a 12V USB C to DC cable like the Blind Spot that I’ve seen mentioned here before.

Had anyone had any luck powering their gear successfully and safe using that combo of cable and charger? Any particular ones to recommend?

To my understanding, I need to find a well-made charger from a respectable brand that allows output for 12V and 1.25A (or more). How does the PD thing work exactly? Chargers specificy several outputs. Am I understanding it correctly that the cable tells the charger what it needs and the charger then provides that if possible (i. e. if the charger specifies that it can output the voltage the cable is asking for)?

What happens if the cable ask for something the charger can’t provide? Does it send anything back?

#83

I have a 12V 7.5 amp power supply from a security camera system, it can power 3 digi boxes and a keystep pro simultaneously but it does do the “reset all devices during boot up” as slicetwo mentions. The issue is that a “surge” is caused when each device tries to pull peak power which happens on start up, after they settle into their operating state there’s no issue.

As robot mentions, there’s an issue here with the brick being capable of supplying that much power max but somehow due to mediocre design not maintaining that power when a load is put on it and a lot of electronics are rated at pulling plus/minus 15 percent above or below load and usually a power supply is rated to accommodate for that.

As it stands, in my case, even though I know it can power all 4 devices simultaneously if I use that I limit it to 3 of them and not all 4. Not sure how much safer it is, but I feel like it has a lower chance of resetting once everything is up and running than if I push it to the limits with the fourth device. The brick I bought was also like $11 so it wasn’t going to be much of a loss if it didn’t work, I wouldn’t invest too much money into this particular solution.

I do think that with a really high quality psu of equal rating with a better tolerance to fluctuations you could do more and have it be reliable.

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#84

Yeah, whenever I need a new power supply I check for JameCo and Meanwell options.

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#85

Personally I’d expect a more powerful PSU (within limits) to be actually cheaper, because there are less parts, less materials, and less production and logistic steps involved.

For example, consider the cost of a PSU for a desktop computer, you can get 600W for under $100 even if you pick a premium brand. 600W would meet the specification of 25 Syntakt PSUs.

I wouldn’t say $50 for a 12W or 24W PSU is a reasonable price at all. A switching PSU is pretty old and proven technology these days, it is the most manufactured electronic device, simply because you need one for every device that is not powered by disposable batteries.

Take a look at what Anker has to offer, (a reputable brand IMHO), you get 20W for $13, 30W for $19. But this is USB-C, so it includes additional parts and a more expensive port than a a simple DC barrel plug. Thoman has PSUs with that spec for €15-20. I bought one to try it out a year or so ago, and to my surprise I found I had never switched back to the original PSU, so I’ve been using that on my ST for a year now without noticing.

Under $100 and you may be literally playing with fire.

Hundreds of millions of desktop computers with PSUs under $100 would beg to disagree. Again: this is old and proven technology, and as long as the PSU (and the cables you attach) can handle the power the devices draw, there is no problem with daisy-chaining 4 (or more devices) that use that power.

The only problem you can get is when devices are not built well, so they start affecting each other or the PSU, that is sometimes the case with effect pedals, but not to be expected with well-built digital devices like the Elektrons.

Even though it might be tempting to get an USB PSU, because you get a 4-6 port charger with 160-240W from reputable brands, remember you will pay a hefty premium for USB-C cables and Birdcords that provide the exact same service as a simple cable with a barrel plug for under $1 with a standard PSU.

#86

You are comparing apples and bananas here.

PC power supplies are built in volume, that goes a long way to keeping costs down. But they are also intended for applications like powering HDDs where noise isn’t much of a problem or powering motherboards and GPUs where additional power-smoothing glue is built in to the current sink (mobo/GPU).

No one uses PC power supplies for audio applications, they use power supplies that target industrial or medical applications. Those are much more expensive than PC power supplies.

Check out the Synth DIY subforum of MW for extended discussions and flame wars on the topic.

I use Anker and Sabrent almost exclusively for USB hubs, power distribution and batteries. Very good stuff.

Thank you for making my point for me. USB isn’t a viable solution because USB-A supports a maximum of 2A without nonstandard extensions, and I have yet to find a USB-C brick with more than two ports. And quality USB to barrel adapters are not cheap.

If you want to plug cheap adapters with fake compliance logos and under-spec’d components into your Elektrons, then be my guest so long as you don’t live in the same building as me.

The situation is worse if you play out: clubs often fail to meet local fire standards, and the results of even a small fire within a crowded club environment can be horrific. :cry:

Incidentally, I just bought this Anker Power bank for travel. I’ll post more once I’ve received it and tested it out with my USB-C audio devices.

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#87

I’m sure you are absolutely right about noise and all that. I brought up PC PSUs only in relation to your claim that a sub-100$ PSU is a fire hazard.

I took a quick look at the Meanwell quad power PSUs mentioned by @thermionic, they offer multiple outputs, I guess these would qualify as “industrial”, you can get those for way under $100. No ideas about the noise, though. Might get one and test it.

I haven one Aukey and one Baseus PSU where the USB-A is rated 15W (and the USB-C port gives another 45W or 60W). They both reliably power my Digitakt even while my Macbook is charging.

I also have a 90W Sabrent 16-Port USB-A hub that also can power my DT and lots of other stuff.

Satechi has a 6xUSB-C port charger with 200W for $150 and two chargers with 4x USB-C. Anker Prime 240W, and Anker 747 (150W) both provide 3x USB-C plus 1xUSB-A. The cheapest option in that list is ~$120.

Ah, I can see how that might be confusing. That was not at all what I wanted to say. I referring only to thecable: an expensive USB-C cable plus a Birdcord plugged into an USB-charger serves the same function as a sub-$1 cable in a standard PSU: transfer power to the device.

#88

For what it’s worth, my Overstayer Modular Channel came with a Meanwell brick.

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#89

I think there are cheaper options, with similar capabilitys, but these ones tend to have ultra low noise, and are designated for such a task.

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#90

Meanwell sure has a loads of different PSUs, I checked out their medical grade table top 12V PSUs, here’s a selection:

These appear to be reasonable and well-built choices for powering 1, 3, 4, or even 7 Elektron boxes, provided you can solder your own daisy chain cables, the PSUs come with barrel plugs or Din4, depending on the model).

Is there any chance you can tell us the part number, so that we can see which Meanwell product Overstayer considers good enough for high end audio?

#91

Sure, the GST40A12-P1J 12V, just with a custom tip. Which sure, the no-names on Amazon’s bazaar sell for half the price or AliExpress for a quarter, but we’re just talking $17 here, industrial-grade is well worth the minimal cost.

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#92

Meanwell adapters are well worth the extra spend. I replaced my two Thunderbolt hub adapters with Meanwell because the originals were causing a ton of noise in my audio chain.

Just check the datasheet for the one you’re looking for. The higher amperage ones may put out more noise back into the mains loop (although still lower than cheap PSUs). You’re sometimes better off using two separate ones that one to power two devices.

Don’t daisy chain, get a star splitter. There are plenty of ‘one to many’ adapters on the market, no need to solder your own.

*-R7B refers to a din plug at the end. P1 refers to a 2.5mm adapter.

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#93

Hehe. You’re absolutely right. It’s quite redundant but at the same time it’s quite practical for reducing amount of bulky things in the bag when traveling, if as many devices as possible could share the same PSU and only require a USB-C cable each. And also could be used with a USB-C power bank in the same manner. That said, you’re absolutely right in that it’s an expensive “nice to have”.

Side note: I’m reading some comments on Reddit etc regarding the Push 2 specifically with a solution like this, that it’s very picky about what PSU you use. Although I haven’t really gotten any further explanation for what it is exactly that it’s sensitive about, since the volt/amp/wattage should be the only variables to match. I understand that buying a $1 PSU from AliExpress could introduce a myriad of other issues related to the quality and stability of the power, but I can’t really understand what a well-constructed PSU with the right specs wouldn’t provide that the original PSU would provide?

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#94

You’re technically correct (the best kind of correct :wink: ) Still, the appropriate cables are often advertised as “daisy chain”, even though they do connect devices in parallel, not in series (which would divide the voltage).

What to get would be dependent where the PSU is located in relation to the devices, and how many cables you’d want connected. “Daisy chains” are popular for pedal boards. These two to the exact same thing:

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#95

Without knowing the specifics, I would guess it’s people buying PSUs that don’t meet printed spec and glitch digital devices.

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#96

Depends how they’re wired. You can also wire for voltage doubling or current doubling, which could be the difference between equipment malfunction/damage, or magic smoke, especially at higher currents.

This explains it all better than I can:

#97

And label them all clearly as soon as you get them, or resign yourself to testing them with a multimeter every single time you use one.

Ask me how I know…

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#98

You mean that it glitches digital devices because it doesn’t match the printed spec or because of other reasons? Sorry if it’s a dumb question, I’m just trying to wrap my head around the intricacies of PSUs. :slight_smile:

#99

It’s really not that bad. There is only a single and rather specific case where this might be a problem, and it definitely is safe to buy a cable that looks like the ones in the pictures above (i.e. with more than 3 plugs) that are marketed as splitters or daisy chains. Here’s why:

As the excellent and exhaustive article you linked states, daisy chain and a splitter cable are exactly the same, they both route all devices in parallel: all centers are connected, all sleeves are connected. Whichever plug you plug into the PSU, they will always work as intended and not cause any problems.

A current doubler cable is designed to connect two power sources (two batteries, two PSUs, or two outputs of a single PSU) to one power consumer. For this application, power sources need to be connected in parallel, so that the consumer can draw current from both sources, but the voltage remains the same. This is wired exactly like a daisy chain/splitter cable: center to center, sleeve to sleeve. Therefore nothing bad can happen if you accidentally get one of those and use it to connect two devices to one PSU.

Only the voltage doubler is a different beast: it also connects two power sources to one consumer, this time the power sources are in series, so that the voltage is combined. This cable connects the center of one power source to the sleeve of the other, therefore if you use that in our context (powering multiple devices with a single PSU), it will reverse polarity for one device. You’d want to avoid that, even though I’d expect the Elektrons to have a reverse polarity protection.

But still, you are quite safe from making this mistake, because:

  1. voltage doublers are clearly advertised as such, and not as splitters/daisy chains
  2. the ones I have encountered “in the wild” always have the plug for the device in a different color (often red), which is not the case with splitters/daisy chains
  3. voltage doublers always have 3 plugs, so if you get a cable with 4 or more plugs, you’re always safe, because that is always a splitter/daisy chain.

tl;dr: If you never use a cable with plugs that have different colors, or if you use a cable with 4 or more plugs, you’re safe.

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#100

I wonder if I could use this to power a OT/A4/AR

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#101

It sure packs enough power (you need a maximum of 24W per device to meet specs), it’s center positive.

However it does not use the same plug: should be 5.5mm/2.5mm but is 5.5mm/2.1mm so you need this adapter in between. If you want to secure it, simply use a heat shrink tube.

Here’s a splitter cable that should fit, and here’s another one (different length, different number of outputs).

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