Korg Forums

Both the stock fan specifications and a picture of a fan installation are on the first page of this thread.

Mark

The more I think about it, the more I'm convinced that the fan speed differs not only between the different size key models, but also from let's say a 73 to another 73.

There's got to be something in the BIOS controlling the fan speed that's not uniform.

Some people are reporting loud fans at startup and then it goes quiet, other are reporting the opposite.

Who knows, maybe the 1.5 update will change things..

It may be due to wide production tolerances, especially if they are a relatively cheaply sourced item. Having said that, most fans of this size are pretty cheap to buy any way, especially in bulk quantities.

today I finally got the noiseblocker fan, I mentioned before (XR2 60x60x25 15db/A 14.1CFM).

It's much more silent than the stock fan.

But it's vibrating a little bit, which gives a kind of hum, so I'm still not satisfied by the result.

I can reduce it's hum by using a Zalman Fan Mate 2, but then the hot spot temperature seems to be a little bit too high.

I ordered a Silenx IXP-34-12 fan now (@dfahrner: thank's for the info), which has a different kind of bearing (FDB, fluid dynamic bearings), which I hope will reduce this kind of hum.

I still prefer to position the fan besides the PSU, which seems to give a nice air flow. Some more trials with different kinds of tunnels or pipes didn't give enough advantages to be worth the hassle.
Currently, I mount the fan to suck warm air from the motherboard, which seems to be better than blowing cold air to the motherboard.

Btw.: the PSU produces some hum, when in boot phase. At some point I confused it with the noise from the fan, so beware!

ATTENTION: I want to mention, that anyone opening the Kronos should pay attention to the PSU!
Even if the Kronos is switched off, the PSU may have large voltages inside (loaded capacitors!). This may put you to death if you don't care about. Also, if you keep the Kronos on, you additionally should care about the power connector and the power switch inside, they don't have protection against contact!

aribo61 wrote:ATTENTION: I want to mention, that anyone opening the Kronos should pay attention to the PSU!
Even if the Kronos is switched off, the PSU may have large voltages inside (loaded capacitors!). This may put you to death if you don't care about.

A very good point. Question: the PSU from my PC has an extra LED light which turns off when the capacitors are empty after I have pulled the power cord from the wall outlet. Does the PSU in the Kronos have such a LED light as well?

In maphill's photos on page 1 of this thread, the silicone vibration dampening mounts (those black rubber thingies) are not fully inserted into the mounting bracket, so that when you attach the fan, it is pulled up against the mounting bracket, as shown...if you push the silicone mounts a little further through the bracket (a tight fit, difficult but not impossible, you'll have to remove the bracket to do this), then when the fan is attached, it's not up against the bracket, but is held about 1/16" away (sorry, I didn't take any photos)...then there's no direct fan-to-chassis connection at all, so no vibration is transmitted through the mounts to the metal chassis...

And I want to second aribo61's warnings about working inside the K: lethal volatages! Chance of death! And if you want things to work after you put it back together, be very careful not to disconnect (or even move) any wires that you don't have to, and make sure everything is connected again when you're finished. Basically, don't do this unless you know what you're doing...

df

dfahrner wrote:In maphill's photos on page 1 of this thread, the silicone vibration dampening mounts (those black rubber thingies) are not fully inserted into the mounting bracket, so that when you attach the fan, it is pulled up against the mounting bracket, as shown...if you push the silicone mounts a little further through the bracket (a tight fit, difficult but not impossible, you'll have to remove the bracket to do this), then when the fan is attached, it's not up against the bracket, but is held about 1/16" away (sorry, I didn't take any photos)...then there's no direct fan-to-chassis connection at all, so no vibration is transmitted through the mounts to the metal chassis...

And I want to second aribo61's warnings about working inside the K: lethal volatages! Chance of death! And if you want things to work after you put it back together, be very careful not to disconnect (or even move) any wires that you don't have to, and make sure everything is connected again when you're finished. Basically, don't do this unless you know what you're doing...

df

I did not know that this was possible, so thank you for the clarification. I did have a silicon layer in between the fan and the mount, but it would certainly be helpful if I was able to pull the mount farther through, reducing tension and therefore reducing coupling with the mount. I've already ripped a mount trying to get it through those too-small holes. Hopefully, the new mounts I have coming will be small enough to make it easier.

Thanks,
Mark

maphill wrote:I've already ripped a mount trying to get it through those too-small holes. Hopefully, the new mounts I have coming will be small enough to make it easier.

Thanks,
Mark

Using the end of a Swiss Army knife file to push the last little flange of the mount through the bracket while pulling from the other side, I was able to get it all of the way through...maybe the Silenx silicone mounts are a little smaller in diameter, but they are amazingly tough - I was sure they'd just pull apart...

df

dfahrner wrote: so I replaced the stock fan with a Silenx Ixtrema Pro 60mm (12dBA, 14cfm), using the included silicone vibration dampening mounts (the Silenx is much lighter than the stock fan, and I'm sure the dampening mounts are strong enough to support it df

this fan is 1700 RPM vs the 3000 RPM KRONOS stock fan, I am sure it is much quiter secondary to low RPM? is there any difference in terms of heat? do you feel your KRONOS is more warm on the right side?

I was wondering about the comparative airflow too.

dfahrner wrote:In maphill's photos on page 1 of this thread, the silicone vibration dampening mounts (those black rubber thingies) are not fully inserted into the mounting bracket, ...... if you push the silicone mounts a little further through the bracket......is held about 1/16" away

my noiseblocker damping mounts have two cones in antipodal directions (cone ends outside), so this kind is easier to pull through the holes (the cone end goes through the hole in both directions, metal and fan).

But I think the 1/16" distance between fan and metal isn't enough to decouple the vibration (if the fan has any). I would rather like to have longer "legs" between fan and metal mount to get a better decoupling. This is why I normally use cable ties, they are very easy to install and you can tighten them much as you like. Decoupling of the fan is excellent if they are not tightened too much. Also cable ties are very elastic at right angles to the axis and they behave like springs. You can build geometric constructions which are elastic in all directions.
And cable ties can take big forces, so I think they should be safe to hold the fan in place. At last *everyone* (or at least a technician) has some cable ties flying around, right?

Unfortunately, the mounting position besides the PSU is problematic, as there are very few points to connect the cable ties. There are only the heat spreader of the PSU and the metal mounts of the PSU to the board below it.

For the cable ties, I would need at least points at three sides or corners of the fan, to get a free floating construction.

Here I have only two, so I need to fix the third side with some elastic material between fan and chassis. This results in some of the vibration being transferred to the chassis. Normally I would drill some holes into the chassis and fix the cable ties through them, but I would like to keep the chassis intact.

please take a look here: https://picasaweb.google.com/1085100000 ... directlink

NavidSyed wrote:[The Silenx] fan is 1700 RPM vs the 3000 RPM KRONOS stock fan, I am sure it is much quiter secondary to low RPM? is there any difference in terms of heat? do you feel your KRONOS is more warm on the right side? :?:

Lower RPM, but the blades are bigger (the center motor area is smaller), and the CFM ratings are almost identical...I just hooked up the stock Kronos fan to a 12V supply, and it's moving more air than the Silenx was moving when installed in the Kronos (voltage unknown); at 9V it's about the same - ???...I don't notice the panel (or any other place) being hotter; since someone has simply disconnected the fan without any problems, probably just moving the inside air around is all you need...

df

A German user gave me the hint to use this fan (at extremely low costs, in Germany sigificantly below 10€) as a replacement for my Kronos fan:

http://www.amazon.com/Noiseblocker-NB-B ... =8-1-fkmr1

I replaced the old fan with it today - the difference is day and night!
Now my Kronos fan is hardly audible any more. That was the only remaining problem zone I still had. Now all is working well.

The old fan was fixed with three (!) screws of four: the remainig unfixed edge could just vibrate against the metal chassis. The new fan is ultra-silent in comparison, is mounted in a much more intelligent way and does it's job just as it should be.

I think Korg should definitely rethink quality and mounting of the original fan, if they haven't already.

Thanks for sharing ... I hear also my fan (K61) but my computer is making even more noise. However, when I buy a new PC then probably I need to replace also the fan of the 61 since then that will probably be the most noisy).

jimknopf wrote:
I replaced the old fan with it today - the difference is day and night!
Now my Kronos fan is hardly audible any more. That was the only remaining problem zone I still had. Now all is working well.

was the power cable of this fan appropiate in length? or did u need an extension? also the end power pin ... was it the same as stock fan?? thank you...