Korg Forums

maphill · Full Member Joined: 17 Sep 2009 Posts: 217

Okay, please look back at the first few posts and you should see a lot of pictures and one way to replace the fan.

More information coming later this week.

Mark
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Korg KRONOS 73, Trinity Pro, Monotron,
Roland FA-06 and Fantom 6, Roland TDK-15
Big Knob, Sonar (Previously, OASYS 76)

aribo61 · Junior Member Joined: 22 Sep 2011 Posts: 75

OK, I'm the guy who disconnected his fan...

First, I think this thread had to be opened. The other thread is more about opinions, which is also implied by it's title.
This one is (=should be) about FACTS.
The other one is to decide if you have a unit to be returned or if you have to live with the level of fan noise. This one is to help you, if you decide to change something.

I want to make this clear:
I disconnected the fan to try if the heat would be tolerable.
After the test and comparing it to the Korg arrangement, I think the fan is in general necessary. This is for world wide usage in all those climate conditions and for playing on stage with heat from the Lights etc.
If you use the Kronos in a home studio and you can guaranty a certain temperature range, it might eventually be operated completely without a fan.
But at least you risk a shorter life of the motherboard and may be also other parts.

I took that risk for the test reasoning the motherboard is a standard one and could probably be replaced by something similar (another Atom board with equal or better specs). I took into account, that many parts of the motherboard are unused (no network, no monitor output, etc. only SATA and one USB port). So a replacement would probably not break any feature, as long as the CPU and probably the chipset remains the same.

I did the test, because
1. I didn't want to give it away anymore Smile

2. I really want a really quiet environment
3. I do some silencing with many of my devices (e.g. computers)

I would not say I'm overly sensitive, but I generally don't like noise which is not necessary.
You always have two possibilities to get lucky: either you accept what's going on, or you change it.
So at the end it's worth the risk (for me).
_________________
Korg: Kronos 61, M3, Wavedrum, Kaossilator Pro, Nano*,
also: Yamaha S90es, Alesis Micron, Line6 Variax (guitar), Line6 Pod X3 Live, Launchpad, BCR2000, MPD18, FCB1010

aribo61 · Junior Member Joined: 22 Sep 2011 Posts: 75

now back to the facts:

as I wrote in the other thread, I'm now convinced, that the fan may be necessary on the long term and operation at this speed level was chosen for some reason. I think everyone has to choose his balance between acceptable noise and the risk he is willing to take.

some facts from my last investigation:

When switching on the Kronos, the fan starts with 12V for a short time (fast), then goes down to 5.5V (slow and quiet) and after some boot phase it's operated at 9V (medium).
For me it seems to stay there. I never could hear any frequency change of the fan whether I stressed the CPU or let it idle.

My fan sounds very similar in fast and medium speed.

I got best results with the standard fan by decoupling it's vibration from the metal sheets by using a swinging construction built from cable ties.

Photo

For more silence with the standard fan you would need to change the voltage of the fan, e.g one can connect it between 5V and 12V to get a 7V operating voltage. Then my fan is nearly unnoticeable. But I also found that the cooling is suboptimal then, so the area around the I-G / U-G and sample buttons get warm which indicates a hot spot below them (which is the heat spreader of the motherboard).
The original cooling keeps this area cool, so this is a good check if the cooling works (you need to wait an hour).

So, as a conclusion if combining a better fan with the decoupling and eventually reducing the speed should provide us a good level of silence.

And I think, testing the combination is mandatory.
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Korg: Kronos 61, M3, Wavedrum, Kaossilator Pro, Nano*,
also: Yamaha S90es, Alesis Micron, Line6 Variax (guitar), Line6 Pod X3 Live, Launchpad, BCR2000, MPD18, FCB1010

SanderXpander · Platinum Member Joined: 29 Jul 2011 Posts: 7860

I would be afraid to use a cable-tie suspension thing for serious gigging. Are you happy for now or are you planning to try the suggested acoustifan (or alternative)?

aribo61 · Junior Member Joined: 22 Sep 2011 Posts: 75

one more thing:

especially in this case a well designed air flow would eventually help alot.

How it is designed here, the fan probably doesn't get it's air input from the hot area alone but for some part also from cooler areas. It may even get some of it's own output (which is called short circuit).

If we would prevent such short circuits, we should get a much better result.

I speculate the fan being originally designed for two harddisks or a harddisk and a ssd. I assume they simply left it in place lacking a better solution. May be at the end of the development process they noticed that some cooling of the motherboard is necessary and they couldn't change the whole construction.
_________________
Korg: Kronos 61, M3, Wavedrum, Kaossilator Pro, Nano*,
also: Yamaha S90es, Alesis Micron, Line6 Variax (guitar), Line6 Pod X3 Live, Launchpad, BCR2000, MPD18, FCB1010

jimknopf · Platinum Member Joined: 17 Jan 2011 Posts: 3374

Thanks a lot for the photos!
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Kronos 73 - Moog Voyager RME - Moog LP TE - Behringer Model D - Prophet 6 - Roland Jupiter Xm - Rhodes Stage 73 Mk I - Elektron Analog Rytm MkII - Roland TR-6s - Cubase 12 Pro + Groove Agent 5

aribo61 · Junior Member Joined: 22 Sep 2011 Posts: 75

Bertotti · Posted: Mon Sep 26, 2011 4:05 pm Post subject:

Is here no external venting? Small holes or sLots at either end anywhere? How about a small vent in either end piece drilled in maybe?

panrixx · Posted: Mon Sep 26, 2011 4:08 pm Post subject:

I believe the venting is via the control slider slots.
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Rhodes 73 Mk1; Kronos 88; Synthex; Electribe EMX-1; Motif XS Rack; Yamaha DX7IIFD; Yamaha MM8; Roland Alpha Juno-2; Roland JV-2080; Tascam FW-1884.

NavidSyed · Posted: Mon Sep 26, 2011 4:10 pm Post subject:

aribo61 · Junior Member Joined: 22 Sep 2011 Posts: 75

...next step...

I wrapped the standard fan in a coil of bubble film and forced it into the tunnel between PSU and back plane. Then I applied 7V to the fan.

This way the cooling is much much better than with the same voltage and the fan mounted to the SSD.

The noise is still noticable but it's now a lowpassed swoosh(?) instead of some tonal noise. It's about half as loud as my laptop. The cable tie solution is less noisier at 7V but doesn't cool well at that voltage.

I also ordered this fan:

http://www.noiseblocker.de/en/BlackSilent60.php (the XR2 model)

which has similar specs as the Acoustifan, but is developed in Germany.
This one has good critics at amazon.de etc. and costs less than half of the Acoustifan.

Some of these features made the point for me:

maphill · Full Member Joined: 17 Sep 2009 Posts: 217

panrixx · Posted: Mon Sep 26, 2011 7:22 pm Post subject:

aribo61 · Junior Member Joined: 22 Sep 2011 Posts: 75

NavidSyed · Posted: Mon Sep 26, 2011 7:36 pm Post subject:

a bubble wrap? I personally think it would be a bad idea Embarassed

, and how did you connect the fan to this new location? Question