silent chamber fans ?  

RE: silent chamber fans ?

The filtration kit disables the chamber fans, since they don't help at all, as soon as there's a need for static pressure (like pushing through a HEPA filter).
For that, you need radial fans, like the one that comes with the filtration kit.
The fans in the Core One aren't the most silent, but they aren't bad either. The issue when optimising is, that it's not a round opening in the back, so a 140 mm Noctua or so wouldn't work well and smaller fans are always less efficient.

The standard fans also aren't decoupled via rubber pins and the grid in the back and in front of the fans is blocking quite a lot of air.
Another issue: molex plugs.
Different fans would require to either cut the standard cables and the cables of the new fans, then soldering - or creating your own adapter cables:
Buy two standard 4-pin fans extension cables and a cable with the correct molex plugs on both ends, then cut them all and solder the molex plug on the 4-pin extension socket.
I thought about taking the standard fans out, cutting the grid in the back completely open and printing a sealed/dampened duct with a decoupled 140 mm Noctua industrial fan in the back.
Which brings me to the next issue: good luck finding a 24V, max. 0.5A, 4-pin PWM fan, that's actually better, than the standard fans.
The Noctua industrial fan was the only one I could find and it costs about 50€.

Overall, I just got used to the noise for now...

RE: silent chamber fans ?

But the core one wants a 4800 rpm fan ?? At fan1 and fan2

if I connect a fan to fan3, are there other specs and can I disconnect the two other ones than ?

RE: silent chamber fans ?

Sunon are another well regarded brand who make a huge number of fans, with their "MAGLev" bearings being their quiet variant. It looks like the MF60252V1-10000-A99 (on Mouser as MF60252V1-1000U-A99) would fit the bill - 60x60x25mm 24v 0.5A 4500 RPM (my stock fans are 4300RPM at 40%) BUT that's only 2 pin. As above we need a 4 pin variant, which they do also offer (S99 suffix) but only when made to order in bulk. Sometimes you can find Sunon fans on AliExpress that have been customised for a specific company and are leftovers/rejects because the vendor code is something other than 10000, but I couldn't find an S99 version of this fan anywhere. For reference here's a PDF of all Sunon fans and variants available. However there is a setting in the printer's menu to disable fan checks, which I assume removes the need for a tachometer wire. And I guess you don't need a PWM wire if the fan's max speed matches what you want already. So the 2 wire MF60252V1-1000U-A99 might actually work, but no guarantee it would be any quieter in practice.

I noticed that shutting the top vent muffles some of the noise. Can't do that with PLA/PETG, but I wonder if there's another way we can muffle the noise. I printed this automatic vents mod to hopefully "redirect" some of the sound backwards and muffle it. Inconclusive results but maybe some other kind of baffle could be designed with foam inside to dampen the sound. It'll only make a small difference though.

Equally I imagine the sound coming from the back could also be muffled. I'm wondering if this huge DIY filter mod would dampen the sound, while having such a large surface area filter to not require higher static pressure fans. 

Does anyone have the official Advanced Filtration add-on to comment on whether it's louder or quieter than the built in fans?

RE: silent chamber fans ?

Posted by: @ckobar

But the core one wants a 4800 rpm fan ?? At fan1 and fan2

if I connect a fan to fan3, are there other specs and can I disconnect the two other ones than ?

I sadly have no idea if you can unplug fan 1+2 or if you need a 4800 rpm fan. All I know is that the chamber fans and the filtration fan run at 24V and a maximum of 0.5A. 

I asked the support about unplugging fan 1+2 and using a 24V, 1A radial fan on fans 3 and the reply was that even the "experts" couldn't give a quick answer to that and would need to invest hours to calculate what would be fine to plug into the fan headers. 

Prusa didn't run tests for that scenario and apparently didn't calculate a maximum either.

You can download the full details of the board somewhere on the Prusa documents website, but if you don't want to put the full board into a simulation, you just won't know.

Since I really don't want to fry the board, I just looked for 24V fans with no more than 0.5A.

RE: silent chamber fans ?

I was hesitant to add the filtration unit because I expected the fan to be even louder, but surprisingly, the filtration fan seems to be much quieter than the original case fans. 👍

RE: silent chamber fans ?

Posted by: @fnord-prefect

I was hesitant to add the filtration unit because I expected the fan to be even louder, but surprisingly, the filtration fan seems to be much quieter than the original case fans. 👍

But can it still keep the chamber cool when you print PLA or PETG?

RE: silent chamber fans ?

Well, the fan CAN be just as loud as the case fans, but in the few prints that I made since I attached the filtration unit, it apparently just didn't need to.

So I guess that is a "yes" to your question. 🙂

RE: silent chamber fans ?

Posted by: @jurgen-7

Posted by: @fnord-prefect

I was hesitant to add the filtration unit because I expected the fan to be even louder, but surprisingly, the filtration fan seems to be much quieter than the original case fans. 👍

But can it still keep the chamber cool when you print PLA or PETG?

Huh, upon further inspection it seems like the filtration fan does not increase power when the chamber gets warmer.
I am currently printing PETG and it is now around 40° instead of 35°.

RE: silent chamber fans ?

You probably need to raise the Chamber Fan Limit from the default 40% to maybe 60%.

The speed curve of the filtration fan might be different to the standard fans and therefore might need a different speed limit. 

Which will probably mean identical noise.. 5°C is quite a lot with the standard fans, so you probably end up with a pretty high filtration fan speed.