No hard drive on Classic II: can I lower fan rpm/flow? experiences?

[foxtrot81]

I have a Classic II w/o internal drive. Using external BlueSCSI.

I will upgrade the fan to a Noctua NF-A6x25. - FLX.

I'm Wondering if anyone has similar experience and if I could drive it at lower rpm like 2400rpm (23m³/h) or 1600rpm (17m³/h) instead of 3000rpm (29m³/h.)

Can't find stock fan airflow specs but those would be using the internal drive anyways...

 

[bigmessowires]

No direct experience, but it would make sense to me. You could put a temperature sensor inside the case, and see how hot it gets after a few hours with your new fan.

 

[foxtrot81]

No direct experience, but it would make sense to me. You could put a temperature sensor inside the case, and see how hot it gets after a few hours with your new fan.

thanks! any temperature value cutoff I should be worried about?

 

[bigmessowires]

I'm not an expert at this and maybe somebody else can give a better answer. ICs are usually rated to at least 85C and often higher, maybe 125C. But CPUs are often rated lower, perhaps 50C. If you have a thermocouple and can measure the temperature directly on the surface of the CPU, that would be best. But that might be impossible due to heat sinks on the CPU.

If you're measuring the air temperature, then I would guess the air temp will be lower than the surface temp of the ICs so you'll need to aim for a lower temperature number. As long as it's not too much hotter than room temperature, I would guess it's OK. Maybe 90 to 100 F? You might get a better answer in a PC overclockers forum.

 

[Phipli]

If you measure the air temperature before any changes, then afterwards, you can just measure the air temperature, because if it is lower, then the CPU will be being cooled better. You'll need to measure the temperatures in the exact same place, so firmly mount the temperature sensor to something (isolate it from its mount with an insulating material).

Relative measurements avoid hard work.

 

[Byrd]

If it has a fan, keep a fan. You can hardly hear the stock fan as it is in a Classic and other components can get warm, just like the HD. I’ve found that any fan that pumps out less than 20CFM feels like it is doing absolutely nothing.

 

[joshc]

Depends what you're trying to achieve - a silent Classic is not really a thing, it needs a fan. The analog board is full of cheap components and generates a lot of heat. Unless you want to deal with other problems later on, keeping the right cooling in there is important.

 

[rplacd]

As a heads up, I've managed to make my Classic II effectively entirely silent using the rubber interposers that you can insert between the case and the screws that keep the CPU fan in. I actually use Silenx fans, which do a slightly better job at reducing noise.

I think there are other ways you can deaden the noise of a fan without necessarily compromising on airflow and performance.

 

[ironborn65]

I have heard comments that the noctua fans are indeed silent but the RPM is low, and as such they can not extract as much heat as the more noisy one, resulting essentially useless.
Any comments with experience to share?

 

[CircuitBored]

I have heard comments that the noctua fans are indeed silent but the RPM is low, and as such they can not extract as much heat as the more noisy one, resulting essentially useless.
Any comments with experience to share?

For larger fans it depends entirely on which type of fan you buy. Noctua sells a variety of fans that are all designed with different use cases in mind. Last time I checked they sold four or five types of 120mm fans alone, with speeds ranging from under 1000rpm to 3000rpm.

The 60mm Noctua that I put into my Classic does the job well, as does the one in the SE/30. That said, the SE/30 definitely gets a little bit toasty with the 040 and graphics card in there so I'd like to cram another fan in there at some point. The smaller Noctuas are not particularly quiet but it's hard to move a lot of air quietly at all, particularly with a small fan.

 

[rplacd]

The 60mm Noctua that I put into my Classic does the job well, as does the one in the SE/30. That said, the SE/30 definitely gets a little bit toasty with the 040 and graphics card in there so I'd like to cram another fan in there at some point. The smaller Noctuas are not particularly quiet but it's hard to move a lot of air quietly at all, particularly with a small fan.

Hmm... where would you mount the extra fan?

 

[zigzagjoe]

A HDD is responsible for 2-4 watts idle and up to around 6 if you are pounding it with reads/writes - it's not a huge difference when idle power is ~30 watts.

I never recommend downgrading fan specs / putting a noctua in a vintage machine. As @joshc said... these aren't intended for silent running, and the classics in particular with their combined analog & power supply board were never the most reliable to begin with. Cutting corners on cooling is asking for trouble.

If you want to make things quieter, you likely could design an adapter to use a quieter 80mm fan in place of the 60mm while moving the same or even more air. Folks have done this for the Color classics already, iirc.

For SE/30, especially a fully upgraded one I recommend this fan: Pico Ace 25 60mm Brushless Cooling Fan - 12V DC - 15.5 CFM - 25dB 109R0612F415 . Cheap to find NOS, made in japan, and it's the upgraded version to the sanyo model originally shipped with the machine. Power consumption and sound levels are about the same, but moves about 20% more air in my pseudoscientific tests. Upgrading to a higher flow fan is about all you can do to improve airflow unless you want to cut holes in your bucket.

Biggest thing you can do to help cooling on a SE/30 is a Seasonic PSU - the efficiency improvements help *a lot*. On the same upgraded machine, I found 10-12 watts less drawn at the wall changing to the seasonic. Here's some data I have:

SE/30 #1: 128MB, 2GB HDD, Micron Grayscale, Maccon, Diimo 030, original Sony PSU: 60 watts @ finder
SE/30 #2: 32MB, 500MB HDD, Interware Grandvimage, Maccon, Carrera 040, Seasonic PSU: 55 watts @ finder

Every piece of #2 is more power hungry but it stills ends up consuming less power - that efficiency goes a long ways. Unfortunately, this is not possible on the classics without serious hackery.

 

[ironborn65]

long story short: replacing a fan with a low noise one will reduce the cooling ability, assuming the original fan is not worn out or producing excessive noise.
Is it?

 

[Phipli]

long story short: replacing a fan with a low noise one will reduce the cooling ability, assuming the original fan is not worn out or producing excessive noise.
Is it?

Long story short... see long story for details.

The sound produced by a fan can be significant reduced by mounting design, bearing selection, cleaning, lubrication and blade design, but a significant amount of fan noise is from air movement itself.

Generally start by lubricating the bearing and cleaning the blades. If you really want, try placing a soft gasket between the fan and casing, but ensure you maintain the seal or air will leak past and recirculate without useful cooling.