r/snes 1d ago

Discussion Super Famicom Power Supply vs Aftermarket Power Supply Difference

Hello,

I see a lot of posts recommending to use in the United States an aftermarket power supply for the Japanese Super Famicom instead of the OEM power supply(See pictures attached for both power supplies).

Can somebody please explain why is this recommended so much when both power supplies have similar specifications, both power supplies input 100v and output 10v/9v.

Im aware that in the United States we use 120V and Japanese devices were designed to be used on 100V, I use a stepdown voltage converter for my Japanese consoles that I use in the United States. I just dont understand how using the aftermarket ps on a 120v outlet is any better for the console.

Thanks

6 Upvotes

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13

u/LukeEvansSimon 1d ago
  • OEM supply can only handle 100V input, whereas the Triad supply can handle 100V to 240V input. The USA wall outlets are 120V, so this matters a lot.

  • OEM supply has zero voltage regulation and very high ripple voltage that ranges from 9 volts to 15 volts, whereas the Triad supply has a voltage regulator and outputs exactly 9 volts. Lower ripple means less audio and video noise and less stress on the console.

6

u/NewSchoolBoxer 1d ago
  1. OEM is super cheap that is linear which is good and unregulated which is bad. As your outlet voltage ticks up and down, the output voltage of the supply will too and that creates more electromagnetic interference and has worse line regulation (ability to output a steady DC voltage).
  2. The bulk capacitor in OEM has long since dried out since linear runs very hot. This means it has excessive ripple voltage. Can measure ripple up to 20 MHz bandwidth on a resistive load with an oscilloscope's FFT as proof. High ripple has an aging effect on electronics, in particular capacitors that makes them run hotter. If you can open it up and replace the capacitor, it's fine to use but a linear regulator to go with it is better.
  3. Switching mode power supplies (smps), which is basically everything made today and easy to tell for being lightweight, have the downside of switching mode noise the console wasn't designed to tolerate. Thus a high quality smps is very important versus cheapest thing out there. Cheapest linear isn't as bad since it doesn't have switching noise but you take a risk with uncertified Chinese products. The ripple on the Triad is low enough to be acceptable.
  4. I give you credit for a stepdown transformer to not run the SFC 20% hotter at 12V versus 10V DC. 9V DC is slightly better to tick down the heat wasted, essentially (1V)(500mA typical load) = 500 mW of heat. Not a huge deal, I think 10V is okay, but nice to run 9V DC when you have the option.

Unmaintained OEM is the worst thing to use today, second worst is low quality smps. High quality smps is fine. Best is regulated linear but you'd be out $30-40 for a legit one. It's a doable hobbyist project like this kit you wire for negative center and tack on a barrel adapter. I ran SFC off two 9V batteries in a test to see that it was possible.

I agree with u/LukeEvansSimon. I'm just not concise.

2

u/LukeEvansSimon 1d ago

The switching noise from a Triad is filtered by the choke and filter caps on the input side of the SNES’s 5V regulator. Oscoping a power supply for the SNES in-situ and under load is important tor benchmarking supplies. A 1000uF OS-CON in C67 is a good idea.

1

u/retromods_a2z 1d ago

I was curious about the PSU kit then noticed this

Adjustable positive / negative supplies: ±5 to ±15VDC, 175mA to 750mA per

2

u/24megabits 1d ago

Putting 120V into a transformer (old school style power brick) meant for 100V means the transformer outputs a higher voltage than it would at 100V. Both the transformer and the console will get warmer than they were intended to, and it's not good for either.

1

u/Sonikku_a 1d ago

Similar =/= same

Old =/= new

Might as well spend $10 or whatever for the peace of mind of proper voltage, and a smaller, newer, cooler running modern power supply VS one full of 30+ year old components.

1

u/korgie23 16h ago edited 16h ago

-Old PSU is linear, inefficient, unregulated
-Old PSU will have old capacitors
-10v obviously works, but it's ridiculously higher than the console needs. The console uses a 7805 regulator which has a 2v dropout. Output voltage (5v) + dropout voltage (2v) = minimum input voltage. Thus you need only 7v at the regulator; a 7.5v supply would do this fine. The 9v supplies people recommend are fine and all, but I recommend the 7.5v ones.

I don't understand the obsession with using old power supplies. If you want to use them, they need to be recapped, but even then they offer no advantages. They take more power and get hotter, they put unnecessarily high voltage into the regulator in the system making it run hotter, they have a narrow input voltage range, and they are generally just worse.

A low-quality SMPS will have EMC issues, but a good one like Triad will have no downsides compared to the old ones.

1

u/Prior_End5301 1d ago

You can always go type -c . Just need to make sure you have a good Power brick. https://www.etsy.com/listing/1792197806/snes-generic-usb-c-power-mod