Bad idea to share power supply between equipment?

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sofakng
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Bad idea to share power supply between equipment?

Post by sofakng »

Can somebody verify if it's a bad idea to share a single power supply between equipment?

Assuming both (or multiple) devices require the same voltage (and barrel jack/polarity, AC/DC, etc) then is it OK to use a larger supply or does this cause video/audio issues?

I've heard this is a bad idea because it can cause interference, but how is this different from two power bricks sharing the same power strip/surge protector?
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NewSchoolBoxer
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Re: Bad idea to share power supply between equipment?

Post by NewSchoolBoxer »

Say you have a 9V/1A brick/PSU and everything you would connect to it takes 9V and is the correct polarity. 99% of the world is center positive but the majority of 8 and 16 bit consoles went center negative. You have a barrel splitter to power two things at once.

1A is 1000mA of capacity. If one device takes 500mA and another takes 250mA, you're good. Of course you may have no idea how much current the devices draw. SNES PSU is rated 1A or 1.3A but I've never measured it pulling more than 600mA. Makes sense to give the PSU some "headroom" to spare. Plug in a Bluetooth controller which powers using the console's +5V rail, that consumes an extra 100mA.

It's fine if you stay within the PSU current limit printed on it but there is still a downside like you're thinking. I would expect more noise on the 9V supply since the ground wire is picking up noise/interference from both devices you're powering. Doesn't mean the extra noise is significant. PSU will run hotter due to more current and that will slightly tick up the cable's impedance. Again, may not be significant.

Two bricks sharing the same surge protector, that's better but debatable how much better. Everything is relative. Where you see this sort of topic come up is with audio amplifiers due excessive noise being audible. Can read about ground loop isolators that are fairly cheap and plentiful.
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Sumez
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Re: Bad idea to share power supply between equipment?

Post by Sumez »

The biggest reason to do this I think is simplifying a console setup. It's annoying having to keep 10 power bricks all plugged into a whole series of power strips just to be able to turn on anything you need when you need it.

So I'm assuming in this context, you'd actually only very rarely even have more than one console turned on at the same time?


On paper I'd say it sounds like it should work, for the same reasons NewSchoolBoxer is also going through. But at the same time, my experience also tells me there is always a whole bunch of gotchas I don't understand when it comes to these kinds of circuits.
ldeveraux
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Re: Bad idea to share power supply between equipment?

Post by ldeveraux »

RetroGameCave has their Trio line to combine sega consoles to the same wall wart. That seems to work for them, I don't see why the logic wouldn't translate to other products with similar power capabilities.
kamiboy
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Re: Bad idea to share power supply between equipment?

Post by kamiboy »

I made my own frankenstein monster of a cable octopus by buying a barrel jack splitter, where I then cut and soldered the wires backwards for center negative consoles. Now I have 6 or so systems powered off of a single 10V 2amp brick that I fished out of the residential e-waste bin. It works well, and should easily handle up to two systems turned on at once, though I never do that. I only wish someone made a professional version of this, modular, powered by usb-c on one end, or straight into the wall, and lots of modular sockets on the other end where I could plug in many cables to deliver various voltages with desired polarity, or just all ~9-10V 2A at desired polarity, and ending in jack type suited to any 8/16 bit console of choice. Would reduce clutter greatly. Should be simple enough to design and build, so for the longest time I have wondered why no one has addressed this retro niche.
ldeveraux
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Re: Bad idea to share power supply between equipment?

Post by ldeveraux »

kamiboy wrote:I made my own frankenstein monster of a cable octopus by buying a barrel jack splitter, where I then cut and soldered the wires backwards for center negative consoles. Now I have 6 or so systems powered off of a single 10V 2amp brick that I fished out of the residential e-waste bin. It works well, and should easily handle up to two systems turned on at once, though I never do that. I only wish someone made a professional version of this, modular, powered by usb-c on one end, or straight into the wall, and lots of modular sockets on the other end where I could plug in many cables to deliver various voltages with desired polarity, or just all ~9-10V 2A at desired polarity, and ending in jack type suited to any 8/16 bit console of choice. Would reduce clutter greatly. Should be simple enough to design and build, so for the longest time I have wondered why no one has addressed this retro niche.
It's been addressed, see the post above yours...
kamiboy
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Re: Bad idea to share power supply between equipment?

Post by kamiboy »

How has it been addressed? You mean the retromancave trio thingy? That is a far cry from what I described. My own concoction can already power more than 5 different systems from a single brick.
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Re: Bad idea to share power supply between equipment?

Post by ldeveraux »

kamiboy wrote:How has it been addressed? You mean the retromancave trio thingy? That is a far cry from what I described. My own concoction can already power more than 5 different systems from a single brick.
OK then, no need. That's what power strips are for.
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Sumez
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Re: Bad idea to share power supply between equipment?

Post by Sumez »

Also doesn't help that they are only making US power supplies. In general I'd be careful about where I buy power supplies from, and a lot about theirs seems kinda dodgy.

Kamiboy, I'd love to see your PSU concoction next time we meet! I should try to make something similar for myself, it would help with a lot of clutter.
Not sure how anyone could possibly think power strips would be able to create less clutter.
kamiboy
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Re: Bad idea to share power supply between equipment?

Post by kamiboy »

My concoction is pretty simple really. After some searching I found a barrel jack splitter that has a single female jack one end, and several male jacks on the other. I think about 6 exits. Then I took some of those male jacks, cut them and soldered them on backwards, to be center negative. Then I labeled each output and used barrel jack converters to connect them to consoles that have the non common jack sizes.

Another approach could be to open up a brick then solder on several barrel jack cables to the outputs inside, each for one console with the correct polarity. It is not pretty, but hell of a lot more tidy than a murders row of bricks.

The only problem with the splitters are that they then to be short on the exit end, so consoles cannot be very far apart, but I suppose one could remedy that with extender cables, just to further complicate things. As I said, it is such a simple thing that it is wonder no one has spun a professional product around this. With how efficient and compact modern GaN chargers are one could make a very neat tiny unit that could power ones entire 8-16bit collection.
ldeveraux
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Re: Bad idea to share power supply between equipment?

Post by ldeveraux »

kamiboy wrote:My concoction is pretty simple really. After some searching I found a barrel jack splitter that has a single female jack one end, and several male jacks on the other. I think about 6 exits. Then I took some of those male jacks, cut them and soldered them on backwards, to be center negative. Then I labeled each output and used barrel jack converters to connect them to consoles that have the non common jack sizes.

Another approach could be to open up a brick then solder on several barrel jack cables to the outputs inside, each for one console with the correct polarity. It is not pretty, but hell of a lot more tidy than a murders row of bricks.

The only problem with the splitters are that they then to be short on the exit end, so consoles cannot be very far apart, but I suppose one could remedy that with extender cables, just to further complicate things. As I said, it is such a simple thing that it is wonder no one has spun a professional product around this. With how efficient and compact modern GaN chargers are one could make a very neat tiny unit that could power ones entire 8-16bit collection.
I've been replying tongue in cheek here, but you've also made my point. You created something that solves a very niche problem and isn't a perfect solution by your own admission. If you've done it to prove you could, then I'm certainly on board. If you're trying to change the system, then good luck. The fact that you don't have a perfect solution shows why nobody has marketed this yet. Isn't it really a slight improvement over current tech? You're eliminating what, 5 power bricks that come with the systems they power anyway? And those would usually sit attached to a surge protector in or behind a cabinet. Then you have to buy extensions for your power cables. I just don't see the benefit here other than 'because I wanted to.'
kamiboy
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Re: Bad idea to share power supply between equipment?

Post by kamiboy »

The only thing missing from my solution is elegance since it is something cobbled together, instead of something professionally manufactured. If you don’t see the benefit then that is because the product is not for you. I don’t have much room to work with and like to keep things neat and tidy, even in unseen places.
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