I need a 120mm x 25mm 12V cooling fan. The 2 in my amp (Adcom GFA-5800) are worn out & noisy.
These are 2-wire, low-rpm & don't move a lot of cfm. Most everything I'm seeing on Amazon are the opposite.
These are 2-wire, low-rpm & don't move a lot of cfm. Most everything I'm seeing on Amazon are the opposite.
I second the Noctua, and specifically this one:https://www.amazon.com/Noctua-redux...=se&keywords=noctua+p12&qid=1734914556&sr=8-5
It's 3-pin, just ignore the third pin. Black wire is ground, red wire is V+.
It's 3-pin, just ignore the third pin. Black wire is ground, red wire is V+.
OK I did some checking and the 3rd wire (yellow) is just a tach lead that tells a computer motherboard how fast the fan is running. It's not needed for this application.
Thanks for the pointer! The -ULN fans are rated super quiet and spin rather slow--exactly what I'm looking for.
Thanks for the pointer! The -ULN fans are rated super quiet and spin rather slow--exactly what I'm looking for.
Use mains powered fans, check the data sheets.
Low voltage fans have a DC to AC conversion PCB inside, and have lower life.
The fans with bush bearings tend to be quieter, tthe ones with ball bearings are more durable.
Just buy whatever is easily available, wire them through the mains switch.
Look for 'panel cooling fan', they are utterly common, a 4 " 2800 rpm fan shifts about 100 cfm.
Low voltage fans have a DC to AC conversion PCB inside, and have lower life.
The fans with bush bearings tend to be quieter, tthe ones with ball bearings are more durable.
Just buy whatever is easily available, wire them through the mains switch.
Look for 'panel cooling fan', they are utterly common, a 4 " 2800 rpm fan shifts about 100 cfm.
This amp has a rather elegant closed-loop variable-speed DC fan drive that I don't want to give up.
The original fans would spin at as little as 3.6V. The only question I have is whether the newer brushless fans will operate at that low voltage.
The original fans would spin at as little as 3.6V. The only question I have is whether the newer brushless fans will operate at that low voltage.
You can actually lube the existing fans...
Peel off sticker, there is a rubber plug, remove, add a little grease + oil, a few drops, then move the fan against the axial sleeve to work in the lube, then put the plug back in place, remove excess lube with alcohol, put sticker back.
That usually works, and extends their life, provided the fans are turning.
Peel off sticker, there is a rubber plug, remove, add a little grease + oil, a few drops, then move the fan against the axial sleeve to work in the lube, then put the plug back in place, remove excess lube with alcohol, put sticker back.
That usually works, and extends their life, provided the fans are turning.
If it is a closed loop type control, which means you need the tacho output type 3 or 4 wire type...not needed in my opinion, but the control circuit may go bonkers looking for the fan.
So try lubing them, if not satisfied, replace them.
Brushless type may be BLDC, another can of worms due to electrical noise.
Stick to the original ones.
The mains operated ones are usually squirrel cage type solid rotor, winding only on stator, usually work from 85-130V AC for 110V normal volts, and similar band for the 220V (180-250V).
So try lubing them, if not satisfied, replace them.
Brushless type may be BLDC, another can of worms due to electrical noise.
Stick to the original ones.
The mains operated ones are usually squirrel cage type solid rotor, winding only on stator, usually work from 85-130V AC for 110V normal volts, and similar band for the 220V (180-250V).
In playing around with a few to see how quiet they'd go at low RPM, I've found they all spun at much lower than 12v (of course, I'm commenting on 12v rated fans). However, I can't remember if any were brushless. The quietest I've heard were Vantec Stealth brand, but I'm not sure if they're still around.
+1 for Noctua.
These are a little noisier but move more air (as far as I can figure anyway):
https://www.bequiet.com/en/casefans
Tom
These are a little noisier but move more air (as far as I can figure anyway):
https://www.bequiet.com/en/casefans
Tom
I did try lubing the 30yo fans. That stopped the scraping sound but the rumble continues. They're worn out.
THIS closed-loop circuit uses a thermistor in the DC drive circuit to set the speed. Tach feedback not needed.