KRONOS Fan Information

[maphill]

Please read before posting in this thread

The other thread(s) about the fan have become cluttered. This thread will be information-based, focused on improving the situation for those who care. If you aren't bothered by the sound of your fan, then this thread is NOT for you.

This thread will NOT be for the following:

• -Complaining
  -Arguing about whether the fan is a problem
  -Criticizing people who care about the fan noise

This thread WILL be for:

• -Determining if your fan is typical (small focus)
  -Working on improving the fan noise (main focus

Thanks, and let's see if we can help each other out with some good information here.

Mark

EDIT: Read subsequent posts on this page for a fix.

[maphill]

First, some information (hidden in the other thread) that may help you determine if your fan noise is typical or not.

Important! Subjective observations like "it seems loud", or "its louder than my laptop" are worth a little, but they are affected by many uncontrolled variables, your perception, and are still relative observations. They are only a little helpful, and sometimes confuse the issue. The only dependable way to determine if your fan is "broken" or out of the ordinary, is to measure it. Even that (because many SPL meters are miscalibrated or bad at quiet volumes) can have error, but it will be more reliable than all the opinions.

If you can make measurements, please PM me with them and I'll add them here so we have some good information.

Preferred location for measurements:

The tip of the SPL meter 1/2" directly above the master slider on the keyboard face. This is preferred because it allows a louder (more reliable) reading with less room noise (relatively). Be aware that measuring a fan closer than the standard distance (I don't remember if it is 1 foot or 1 meter) will give a higher reading, so don't compare these measurements to the "ratings" as they are not measured in the same way.

Use a dBA measurement, in a quiet room. Probably "slow" setting.

2 Kronos 73 Models (and OS version):
1. 38 dBA
2. 39 dBA (1.0.4)

I believe these are "typical", but only more people measuring and adding to this data can confirm this for sure.

EDIT: I no longer believe this is normal. Now that I have replaced the fan (the 3rd time) it seems just like some other people's fan descriptions ("I have to place my ear by the slider to even hear it). Read posts below for more information.

Important If you believe that your unit is significantly louder, then the right thing to do is to contact Korg support and have them take care of you.

[maphill]

Important: If you open your KRONOS, you do so at your own risk. It is possible that you could void your warranty. It is also possible you could mess something up. I am not responsible for any negative consequences of anyone opening up their unit.

I have not yet found a definite solution to the fan noise, but will show my procedure here so if anyone believes they have found a quiet-enough fan with enough airflow, they can test it. EDIT: I have now found a quiet enough fan, see subsequent posts. This post still shows an acceptable way to replace the fan.

Things to keep in mind:

• It is hard to find truly quiet 60mm fans.
  A 70mm might fit in the case, but would require custom mounting holes (and they often aren't quieter).
  An 80mm fan will not fit in the same orientation as the current fan.
  A given dBA rating does not guarantee the same volume once you install the fan.
  Many ratings by manufacturers are unreliable.

For these reasons, it may be hard to find a fan that is better on all fronts. The fan below (with my mounting method) has less low frequency vibration (less hum) but somewhat more whoosh (hiss). It reads 42 dBA measured as described above.

Procedure

This procedure is designed to be completely reversible, except for 1 cut zip tie.

Put in spacer cards for weighted keys.
Flip over keyboard on pillows or a soft surface that will protect all knobs.
Remove all screws, note the tension on them for when you replace them.

The pictures assume you have the unit upside down with the keys pointed toward you.

Supplies for this work:

• The fan you want to use, and probably a 3-pin fan extension cord.
  Optionally: Rubber mounts and gasket.
  Perhaps small zip ties

<a href="https://picasaweb.google.com/lh/photo/W ... site"><img src="https://lh4.googleusercontent.com/-neeO ... G_1925.JPG" height="640" width="474"></a>

Stock setup. Note, only 3 bolts in place. Also notice the zip tie on the inductor magnet to hold it shut.

<a href="https://picasaweb.google.com/lh/photo/R ... site"><img src="https://lh5.googleusercontent.com/-Skyy ... G_1926.JPG" height="600" width="800"></a>

Back in the left hand corner is the motherboard. This is where the fan plugs in.

<a href="https://picasaweb.google.com/lh/photo/K ... site"><img src="https://lh5.googleusercontent.com/-Yl24 ... G_1927.JPG" height="638" width="800"></a>

Helpful tools:
Small wire cutters.
Stubby #2 Phillips screwdriver
Small needle nose pliers

<a href="https://picasaweb.google.com/lh/photo/t ... site"><img src="https://lh3.googleusercontent.com/-NDma ... G_1929.JPG" height="480" width="640"></a>

The fan can be removed carefully with the short Phillips screwdriver.

The zip tie on the inductive coil must be cut (with the wire cutters). You can then use the needle-nose pliers to pop it open. This is to allow you to run the new fan power cables through the inductor, which helps prevent interfering signals from being transmitted through the wires (from the fan, etc.). This coil can be removed from its flexible mount.

<a href="https://picasaweb.google.com/lh/photo/q ... site"><img src="https://lh4.googleusercontent.com/-hRiG ... G_1930.JPG" height="600" width="800"></a>

Here is the fan removed. You can see how it is up against the side of the SSD. (The blades going past this might be a source of turbulence or cavitation, creating noise). Notice also that there are holes for mounting a 2nd drive. The power for this drive is already present, though the SATA cable would have to be added and run to the motherboard, I believe.

<a href="https://picasaweb.google.com/lh/photo/o ... site"><img src="https://lh5.googleusercontent.com/-7PIN ... G_1931.JPG" height="600" width="800"></a>

In order to insert the rubber mounts, the SSD must be remove (4 screws, be VERY careful to not drop them). By the way, the rubber mounts will not work with the original fan.

<a href="https://picasaweb.google.com/lh/photo/o ... site"><img src="https://lh6.googleusercontent.com/-vSWP ... G_1934.JPG" height="600" width="800"></a>

Insert the rubber mounts from the back. These holes are smaller than is typical for these mounts, so it is a tight fit. You can pull on one end with pliers or fingers while pushing on the other end.

<a href="https://picasaweb.google.com/lh/photo/q ... site"><img src="https://lh6.googleusercontent.com/-S-Uy ... G_1935.JPG" height="600" width="800"></a>

Picture of 3 mounts inserted:

<a href="https://picasaweb.google.com/lh/photo/m ... site"><img src="https://lh6.googleusercontent.com/-S5nN ... G_1936.JPG" height="600" width="800"></a>

Replace the SSD. You can choose to add a gasket to your fan and then install it.

<a href="https://picasaweb.google.com/lh/photo/u ... site"><img src="https://lh3.googleusercontent.com/-Vx7q ... G_1940.JPG" height="600" width="800"></a>

Or you can just use the original screw with a new fan and see if the new fan is an improvement.

Switch the fan power wires. You can leave the existing fan in place so as to not disturb anything.

Secure the fan power wire to the existing wires. Also secure the (now unused) original power wire. I zip tied it (zip ties came with the fan) back on itself.

<a href="https://picasaweb.google.com/lh/photo/Q ... site"><img src="https://lh3.googleusercontent.com/-yQ3F ... G_1942.JPG" height="600" width="800"></a>

Run the fan wires around the inductor as they originally were, and if you have excess cable, make sure it is managed so it will not bother anything.

<a href="https://picasaweb.google.com/lh/photo/O ... site"><img src="https://lh3.googleusercontent.com/-FdRx ... G_1946.JPG" height="600" width="800"></a>

So what about the original fan? I did not want to cut any wires or undo any of the bundles. So, I took some zip ties and ran them through some unused holes...

<a href="https://picasaweb.google.com/lh/photo/w ... site"><img src="https://lh4.googleusercontent.com/-dTkx ... G_1947.JPG" height="800" width="600"></a>

And then secured the original fan to those for now.

<a href="https://picasaweb.google.com/lh/photo/b ... site"><img src="https://lh3.googleusercontent.com/-gUyy ... G_1949.JPG" height="600" width="800"></a>

Then replace the bottom and carefully tighten all screws. I start all the screws by hand before tightening any of them. The small screws don't require much torque. The bigger ones require a little more.

Then, ideally, you will test your machine in a quiet room and measure with a SPL meter to see if the situation has improved.

Please post any data you have.

Questions welcome,
Mark

P.S. Next I'm trying a spacer to see if that helps it run quieter.

[maphill]

I tried the Acoustifan with a gasket. As you see in the next post, it didn't help much, though the rubber mounts lessened the hum.

If you want to try reducing the hum with the stock fan, you'll need special mounts because the stock fan is a closed chassis, and most long rubber plugs for closed chassis won't work because the 60mm fans have smaller holes. However, the following product claims to fit: Nexus Closed Chassis Fan Mounts from www.endpcnoise.com

What worked for me

Thanks to a suggestion later in this thread, I ordered the Silenx IXP-34-12 (NOTE: Not enough airflow, see end of post for better recommendation), which claims to flow the same amount of air as the stocker. I mounted it with the included rubber mounts, and did not use the rubber gasket that I tried above.

[<a href="https://picasaweb.google.com/lh/photo/i ... site"><img src="https://lh3.googleusercontent.com/-Egy4 ... G_2133.JPG" height="600" width="800"></a>

I also pushed/pulled pretty hard to get the nub on the mounts through so there would be a space between the fan and the mounting bracket. I tore a couple rubber mounts in the process, but luckily had extras from all my purchases.

<a href="https://picasaweb.google.com/lh/photo/B ... site"><img src="https://lh6.googleusercontent.com/-X9ZZ ... G_2134.JPG" height="600" width="800"></a>

I'm happy to report it is basically silent! I can now only hear the fan if I put my ear on the master slider!! Measuring it with the SPL meter it reads 36 dBA, just barely over the ambient reading with that meter. A world of difference.

I measured the surface temperatures with the stock fan and the Silenx. I did this with an infrared thermometer. (Room temperature: 76 degrees F)

Stock:
Left side top: 82-84 degrees F
Right side top: 87-89

SilenX:
Left side top: 80-82
Right side top: 87-92

It looks a small bit warmer, but I believe I left it on 30 minutes the first time and an hour the second. It might be that this fan moves a little less air, so I'll keep an eye on it, but I think this is fine. I'll report back with what I find.

If you can hear your fan while in your typical seated position, you have 3 good choices.

1) Return your unit and try again (many people can't hear their stock fans)

2) Try rubber mounts with the stock fan (especially if it is the hum that bothers you), but make sure and get the right ones (small holes)

3) Replace your fan as indicated on this page. Keep in mind that fans do not always sound as good as advertised.

Good luck!
Mark

EDIT: NOTE!! The SilenX fan does not flow the reported airflow, it doesn't flow enough air. Later in this thread, the airflow (and temperature) of fans are measured more methodically. A better (safer) fan that is still much quieter (though not silent) is:

Noiseblocker NB-BlackSilentFan XR2

[maphill]

Unfortunately, 60mm fans are notorious for being noisy. And manufacturers of fans are notoriously inconsistent in rating their fans. But, we have to start somewhere.

___________Factory Unit___Alternative?
___________RDM6025S____Acoustifan AFDP-6025B
Size (mm) __60x60x25_____60x60x25
VDC_______12v__________12v
Current_____0.10 amps____?
Power______? watts_______0.96
RPM________3000________2700
CFM________14.10________13.7
Noise (dBA)__22.71________16.9

The Acoustifan is rated noticeably quieter and delivers 97% of the airflow. Those familiar with manufacturer will recognize that is within design tolerances. It is more expensive (~$22), but a small price compared to the Kronos. And it includes rubber mounts which should help with the low frequency noise. Seems like a good replacement fan for those who care.

http://www.quietpc.com/us-en-usd/produc ... afdp-6025b

Other possibilities (with more airflow):
http://www.quietpc.com/us-en-usd/produc ... /fd-fan-60
http://www.frozencpu.com/products/5221/ ... d=vZedI6HU

My results with the Acoustifan AFDP-6025B:

More hiss, less hum. 42 dBA. Fail.

[popmann]

Sorry...should've more closely read the intent...

[jimknopf]

As I said in other threads, this is definitively interesting to me.

And as I said there, the fan noise is not unbearable for me here, but definitely not something I will tolerate in the long run. The reason is simple:
The quality of the fan and of its connection with the Kronos body to me seems FAR from what can easily be achieved with
- a) a much better fan (quiet quality fans aren't hard to find and the one in the Kronos is definitely NOT one of that kind from my view)
- b) a much better isolation from the Kronos body

Does that mean that I rant about Korg? No, just the opposite!
The Kronos is the most flexible and powerful synth I have ever owned. My readiness to deal with small obstacles in this device is high, and in my book first of all I'm happy that Korg provided such a great synth at that price at all.

But being very positive about this synth doesn't stop me from saying that the present fan noise is definitely disturbing me in home studio use. And I don't care at all, if I have to invest some money into a better solution. All I hope for is a cooperative approach from Korg instead of treating the whole as non-issue by definition.

I admit that I was surprised, how many people in the poll seemed to accept the noise level they meet, but if it is fine for them, that's just great.
For me personally, that doesn't change my conclusion. So any bit of technical help and info is higly welcome to me. The best would be a proposition of one or several more quiet fans with similar or equal airflow and any info with pics how to repalce the present fan, while also isolating it from the Kronos body. Simple and straightforward.

@Sharp: it's important to see that there's nothing hostile about seeking a good fan solution per se. And finally, soon as an technically adequate replacement with significantly lower noise level is found, I am VERY curious to see, how many of those getting by with the present noise level will then suddenly use the alternative solution anyway.

[DavyP]

According to the Poll thread at present there are approx 25% (a quarter) of owners who are disturbed by the fan noise in the Kronos!

That sounds like more than a minor trivial issue to me??

I'm interested in any possible solutions.

[DennyC]

When my Kronos finally arrives, I hope that I'm not one of the 25%.

[runningman67]

Dear Mr Korg

are 25% of Kronos owners wrong?

Dear Mr Korg

is there an issue with the fan noise at Korg HQ

Dear Mr Korg

Wheres my Kronos73

[SanderXpander]

And we're back to debating like the other thread...

In a last ditch effort to get this thread back to its original intent I was wondering if it would at all be worth is to create some actual ventilation hole in the Kronos. I haven't observed the insides and mounting myself, but I figure if you're already voidoing the warranty... A fan blowing hot air out should be more efficient than one blowing it around, correct? And if that's so, it should be possible to achieve lower speeds or less frequent speed ups while still delivering sufficient cooling...?

[jimknopf]

Not sure about this.

Isn't a fan blowing out always louder than one in a case without bigger holes?

My impression was, that the fan just helps to disperse a hot spot or hot spots with limited heat.

Couldn't we just gather basic information first?
1. How much air is moved by the present fan and which silent fan could replace it?
2. How is the replacement done in a proper way?
3. Which kind of isolation is suited best to avoid that fan vibrations reach the Kronos body?

[SanderXpander]

The answer to question 1 is actually in one of the very first posts in this thread.
For question 2, I'm assuming you're looking for something more sophisticated than "gently unplug and unmount the stock fan and replace it with the new one"?
Question 3 is a good one but this requires a lot of testing (and someone willing to do it). Rubber insulation was already tried (as per the other thread) but seemed to make relatively little difference.

[jimknopf]

LOL, you nailed me with 1 and 2

Concerning 1, I just seek confirmation, to be sure I don't buy and use the wrong stuff, or overlook a great alternative.

Concerning 2, I want to be sure that a standard connection is used and just can be replaced.

May sound like being too cautious, but I prefer that over the slightest possibility of running into problems.

[maphill]

Gentlemen,

Just a reminder: Please let's keep this thread for information only. As people try possible solutions, post information here.

Let's not re-hash whether or not the sound is objectionable, that's been covered on both sides.

Now, I'm going to go back to the first few posts and add a lot of information, so be sure to re-read those in an hour or two.

Thanks,
Mark