Good morning!

This is my first post in the forum. My native language is Spanish and I use the Google Translator to translate into English, I apologize beforehand if something is not completely understood.

Well, I have had "white noise" problems in my Kawai CS8 for a long time, it is a sound that does not change with the volume controller and that is reproduced by both the digital piano speakers and the headphones. The sound from the integrated speakers does not bother me too much because to hear it I have to get close enough to the speaker, on the contrary, the sound played by the headphones has always been very uncomfortable, especially when I play at night in complete silence. I use very low impedance headphones 20-30 ohms and I am aware that this fact has surely exacerbated the problem.

I found many people on the internet who suffered the same problem and I was surprised that it was such an ordinary incident among the current digital pianos. After trying all the possible solutions that have been written in this forum (and others) I decided that the time had come to contact the technical service of KAWAI Spain to find a drastic solution to the damn thermal noise produced by the amplifier of my piano.

That night when I went to bed I had a good idea
There are some devices that are used in the car to eliminate the noise from the grounded circuit when one wants to talk by bluetooth or play music, so I intuited somehow that they could be good to reduce the hiss that reproduces my headphones. After all, the worst scenario of this experiment was losing a handful of dollars.
So I bought Amazon this device to test it on my piano.

https://www.amazon.com/product-revi...btm?ie=UTF8&reviewerType=all_reviews

Finally!!

I have completely eliminated the "white noise" of my KAWAI CS8 without losing sound quality, apparently. You only have to plug the device into the headphone output of the digital piano and then connect the headphones to the device. As simple as that.
The sound that the piano emits from the amplifier is reduced, so you should raise the amplifier tab more than normal, but the sound is excellent.

I do not know if someone had already found a solution to this problem, but I also wanted to share with all of you this wonderful fact that has made me enjoy my digital piano again.


Doclad

Hello Doclad, welcome to the forum.

White noise through headphones is not an issue that I can recall reading about from other CS8/CS11 (or CA97/CA67) customers, however I'm glad that you have found a product that enhances your enjoyment of the piano.

Kind regards,
James
x

My Kawai CS8 for some reason reproduces this "white noise". After deeply investigating this issue I have come to the conclusion that the conditions for this to happen have not been discovered yet. It occurs in many models of different manufacturers and in a quite random way.
It's strange.

DocLad

If a ground loop isolator has solved the problem I'm wondering whether the noise in question was "white noise".

Ground loop noise generally comes as a hum or buzz. White noise is a broad-spectrum hiss. The two are quite different.

Also ... how can there be a ground loop when the only item present is a piano (and non-powered headphones) ?

Doclad: I'm puzzled Can you describe the noise that you were hearing?

I wonder if the instrument is properly grounded.

I feel the confusion, I am quite ignorant in this field. I thought that "white noise" was the same as "thermal noise". My fault.

The sound of which I speak dominated in the acute frequencies. It is very similar to the sound that a tocadiscois emits when the vinyl is finished. I have managed to eliminate it completely with this device.

How can I tell if the instrument is properly grounded? Is it something I can solve without having to open the piano?


Doclad

There are youtube videos that play white noise, ground loop noise, etc. Could you find one that sounds most like the sound your piano makes? Or make a recording of the sound and post it. I'm interested in this since I've had various noises over the years and they're always a bit of a mystery to solve. I'm glad but surprised that your solution worked.

Electrical standards are different between countries, but assuming that you live in Spain it appears that you have two different types of electrical plugs, called Type C and Type F.

If your piano's power supply cord has a Type C plug on it, then the ground issue is probably ok assuming that the wires are properly connected inside of the piano (and since it's working otherwise we can probably assume that).

If it's a Type F plug then the first thing to do is to make sure that you're actually plugging it into a Type F socket on the wall. If you are somehow plugging it into a Type C socket, then you have found the problem.

If you are plugging it into a Type F socket then the question is whether the socket is properly wired and grounded. An electrician can tell you this, or you could get a tester like this one and check it yourself. (There are probably lots of different testers available; this is just the first hit on google when I searched the words "type f socket ground tester". Your friendly local hardware store might have one, too.

Frank: How would lack of grounding cause this noise?

Uncle google just found me this:

Grounding and Shielding Audio Devices

The section headed "Chassis Ground vs. Signal Ground" answers your question in some detail.

That white paper discusses cable shielding and grounding ... an entirely different subject.

The OP had a problem with noise from the piano speakers and headphones. There were no cable grounding issues.

Sure enough, my KAWAI CS8 has a type C plug. So this is the origin of the noise I hear from the headphones and the built-in speakers? because they have not mounted an F-type cable like so many other appliances? I do not get it.

Can I buy an additional type F cable and use it on the Kawai CS8?


Doclad

If it has a Type C plug (and came that way from the factory) then it's designed to not require a separate ground wire and that's not the problem.

If the unit came with a Type F plug on it and someone chopped it off and replaced it with a Type C, then all bets are off, of course, and you can probably just buy a Type F plug, remove the Type C plug and change it yourself. But if it came with a Type C plug, then that's how it's designed and you don't need to do that (and won't gain anything by doing it either since there' s no ground wire present.)

Removing a grounded plug and replacing it with a non-grounded plug is a really bad idea on any appliance, regardless of whether it's a piano or an electric drill or a refrigerator. It becomes an electrical hazard and anyone who comes into contact with the device could be seriously injured. (Note that I say could be, not will be: certain other things have to happen inside of the device before it will shock you but those things are the exact reason why the ground wire is there in the first place.)

In short, you won't gain anything and that's not the problem if and only if the power cable that you have on it right now is the one that came with it from the factory, it has a Type C plug on it, and it hasn't been modified by anyone.

No. The power cable should not be related to the noise you hear. These CS8 comes with a non-grounded C plug, not a grounded F-plug. Changing it to an F plug would have no effect, because the ground would not be connected to the power supply anyway.

Have you tried setting the line in level to zero? There is a rotary knob on the control panel near the line-in input. Set it to the minimum (rotate it anticlockwise). There is also a digital "Line In Level" setting on the Basic Settings menu. Set it to 0dB. With the knob set to minimum do you still hear noise? If yes, try to connect your mobile phone to the line in on the CS8 using a male-male 3.5 cable. Do you still hear noise?

Note that the headphone isolation device you are using with your CS8 is not a solution. It is just hiding part the problem but not solving it. Have you ever called Kawai customer support? You should have a technician looking into that problem because your CS8 may be defective.

Was wondering if you tried higher impedance headphones?
If the sound is the same through the speakers, that does sound like normal hiss that amps normally have. 20 or 30 ohm headphones will expose that same background hiss. Wondering how a 200 ohm hp would react

The noise would be less noticeable because the overall volume would be lower. Afaik the headphone amp of the CS8 is not designed to support higher impedance headphones. Only the new CA/NV models have such an headphone amp.

Anyway, a CS8 that is not defective should not produce hiss via speakers or headphones, even at high volume. If it does, something is wrong.

But there are some reports of grounding issues on some CA/CS units, even on the new CA and NV models (please check the corresponding threads). In some units, setting the line in level to zero when that input is not being used solves the problem.

Your saying it’s from the line in even when not in use?

It is a sound that will not change with the output volume of the speakers. It is similar to the whisper you hear when you put a glass in your ear, it seems as if you heard the wind from afar.

My wife says it's a normal sound because the piano is alive. For her it is almost imperceptible. I may have obsessed too much.


Doclad

Thank-you for responding. It’s a normal sound yes. I was just wondering if you tried higher impedance headphones?

Yes. When nothing is connected to the line in and its volume is set to medium or high some units generate white noise. With the line in volume at minimum or a cable connected to that input, the noise is gone.

There are what seems to be grounding issues as well on the new models with touchscreen (CA 78, 98 and NV10). There are several reports of white noise on the line in input, when Bluetooth is enabled or when the touchscreen is being used. In other cases, the touchscreen/UI reboots when connecting or disconnecting headphones. Kawai had already sent technicians to cut a cable on the touchscreen unit to solve these problem in a number of cases. And the NV10 has a hiss/white noise issue through the speakers that apparently is being investigated by Kawai. However, It is not clear how widespread these issues are. I have a CA98 for one year and have not yet experienced any of these problems. You can check some of the reports on the CA78/98 and NV10 threads. Since the CS models use part of the same hardware as these new CA models, I would not be surprised if the root cause is the same.

Even if I set the volume of my CA98 to the maximum I get zero hiss/white noise through speakers or headphones. So, your unit does not seem to be working as expected. Have you tried reducing the line in volume to zero as suggested? By the way, what happens if you save a couple of seconds of silence using your cs8 to a wave file and then listen to the result (or look at the sound wave) on your computer? It should have no noise whatsoever. This would also mean that your unit has some kind of electrical interference getting into the amplification circuits.

I can tell you have great trouble shooting skills but all amps with speakers have a background noise level typically and it seems the OP is just hearing the idle hiss.

It sounds like two or three different issues and problems are being mashed together.
I know this thread has run it's course but I just wanted to hear from the OP if he had tried HIGHR Impedance HP's.

I agree with you! I have a very good set of hi-fi speakers and amp and there is always background hiss on that system. But on the mini hi-fi system I have connected to my PC via optical spdif there is no hiss. The same applies to my CA98. Note that the ca98 has a soundboard with two transducers along with 2xmid-range and 2x tweeter . Maybe the hiss is concealed by the cabinet. But I cannot hear it.