The AT PSUs made by Startech until not long ago are pretty silent, but they use sleeve bearing fans which usually fail earlier than other types. I also have a couple of Antec units from back then with temperature-controlled fans, so they are really silent as the fan does not usually need to ramp up due to the low consumption of regular AT-based systems.

In any case, you can always replace a noisy fan with a modern part like an Arctic F8, which should provide similar airflow but with a quieter operation.

well most AT PSU fans are 20-30 years old by now, the only way they are silent is if the bearings have seized up and they're not turning at all :p

apart from still manufactured ones there is not much you can do but replace the fan (or refurbish the old one, but even then it probably won't be as silent).

as long as you don't use any special high powered equipment a more silent fan shouldn't be much of an issue, old PSUs might be very inefficient, but even then power draw is usually not very high.

...and while you're in there it might be a good idea to replace the capacitors as well ^^

usual disclaimer... only open PSUs if you know what you are doing, only when they're disconnected and capacitors discharged.

TheMobRules wrote on 2020-09-15, 00:58:

In any case, you can always replace a noisy fan with a modern part like an Arctic F8, which should provide similar airflow but with a quieter operation.

Most power supply fans are 12VDC, at least in every pre-1995 power supply I've taken apart. (just something to keep in mind) However, it isn't hard to solder into the 5VDC rail.

Other mod to make more quieter PSU is get a low current 12V 3 wire fans with one exception not any fans: Get one from Nidec, San ace/Sanyo, YS Tech, NMB, PAPST. Anything less than 90mA will be quiet. If hair more current, I would try that on wired to 5V instead. This way you get high quality fan and will spin quietly. That providing that heatsink is oversized and of good quality.

Coming from me being deaf using hearing aids bit odd but make sense as I have hard time hearing other sound if the noise is white noise and too loud that fans generates. Back in the day when I had Athlon XP machine, I had to resort to a home made adjustable voltage regulator and 5V mods to run fans, that I have at hand or was with PC, more quietly and that was before I used ebay more.

Don't forget, the type of motor that has very soft magnetic cogging that is very soft vibration when hand-spun tend to be smoothest and transmit less vibration into PC too. The one that cog harshly will buzz loudly like a tired bug trying to buzz off into air when spinning slow at reduced voltage/power, hold one and pick one that is smooth running.

These days, I'm glad for PWM technology.

Cheers,

I sometimes use 24V industrial fans in 12V power to silence my PSUs and computer systems. And if you use them with 12V they will go silently literally forever.

Why not use an ATX power supply with an AT adapter? Those 25 year old AT power supplies are bombs waiting to go off.

Passive cooling of AT PSUs wasn't a thing, but might be an interesting project to do in case of compeltely overhauling/renovating a PSU. What you can easily do however is to replace the old, noisy, unreliable fan by a new relatively silent one (Noctua Redox is my current go-to option).

Sure there are. You take any AT PSU and replace the fan with an 80mm Noctua or Thermalrigh => boom! Quiet AT PSU.

Thinking back then was to use the PSU to exhaust warm air from the case and as such most fans that come with AT PSUs are high RPM and rather noisy.

The idea of using an ATX PSU with an adapter isn't bad either. I already had been looking into silent PSUs for my modern PCs and there are actually even some (more expensive) fanless ones. In addition it would be even cooler if you can just use modular ones to remove the excessive cable clutter in old machines.
So, yeah, that would be a agreat option as well. Found a video about that on philscomputer lab https://www.youtube.com/watch?v=8QXmxdiNWIs
However the links are dead. There and in this forum only a few cards are mentioned which use the -5v thing. But I really hate the idea of having a potential flaw in the system and on every issue you encounter n game then you thing "well, it could be because of that power supply" so, I guess this -5v thing would be the more sane idea. No idea where to still get them though.
Also ATX power supplies changed as well, not having molex anymore. So with super modern ones, you would probably need additional converters for the PCI power connectors / SATA to molex I guess.

Kordanor wrote on 2020-09-15, 18:37:

The idea of using an ATX PSU with an adapter isn't bad either. I already had been looking into silent PSUs for my modern PCs and […]
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The idea of using an ATX PSU with an adapter isn't bad either. I already had been looking into silent PSUs for my modern PCs and there are actually even some (more expensive) fanless ones. In addition it would be even cooler if you can just use modular ones to remove the excessive cable clutter in old machines.
So, yeah, that would be a agreat option as well. Found a video about that on philscomputer lab https://www.youtube.com/watch?v=8QXmxdiNWIs
However the links are dead. There and in this forum only a few cards are mentioned which use the -5v thing. But I really hate the idea of having a potential flaw in the system and on every issue you encounter n game then you thing "well, it could be because of that power supply" so, I guess this -5v thing would be the more sane idea. No idea where to still get them though.
Also ATX power supplies changed as well, not having molex anymore. So with super modern ones, you would probably need additional converters for the PCI power connectors / SATA to molex I guess.

No need for guessing games .

On a card that does not requires -5v , the corresponding finger on the ISA edge connector finger will simply not be connected to anything on the card .

EDIT: Also, a card that requires -5V will simply not work properly without it (ar at least a part of it won't). This will not be game specific .

It's extremely easy to replace a fan in a noisy PSU with a quieter one. I've done is so many times. All you need is to open it, unscrew the fan, cut the wire giving u enough slack. Measure it find another fan. Put your shrink wraps in solder the wires melt your shrink wrap, wire tie if need be, put it back together. It's a good opportunity to check all the caps and components for failure.

If you're just using it with a 386 or 486 system, my recent solution has been to use a laptop power supply > bench PSU (DPS5005) putting out 12v for a PicoPSU. My 386sx only uses about 15 watts max so it doesn't even tax the picopsu much. Otherwise, for real systems with CD drives or pentium CPUs, I usually just buy a cheap TFX power supply, which are usually around £7 and have a smart fan so they're nice and quiet, then an adapter plate & ATX to AT adapter. Much less dangerous than an AT PSU and so much quieter.

I have this

http://www.evercase.co.uk/index.php?route=pro … 3&product_id=94

Which is just an ATX PSU with an adapter but it's a great all-rounder PSU. -5v rail, 25a on the 5v rail (not ideal but better than some modern cheapo power supplies with like 15a) 20pin +4pin as separates for those boards with capacitors right next to the ATX connector so your 24pin won't fit into the 20pin connector, 12v for the CPU, loads of molex, a couple of SATA and a floppy connector. It's also dead quiet with a proper 120mm fan. Enough watts for most retro builds and I've used it for C2D builds to a 486 with Soundblaster 2.0.

Almoststew1990 wrote on 2020-09-15, 22:05:

I have this

http://www.evercase.co.uk/index.php?route=pro … 3&product_id=94

That looks like a useful option until I get to test my older AT PSUs and recap those that need it. Might get one of these for my Batman's Revenge board that'll be here soon.