Yamaha Clavinova w/Rumbling Sound

[Joe Jaramillo]

I have the same problem on a C 430. I’ll be playing either quiet or loud and then a hear A rumbling noise that kind of trails off for a bit and then comes back. Did you ever find out what the root cause was?

I have a Yamaha CLP-411 Clavinova that is about five years old. It has
developed an occasional rumbling sound that comes from both speakers.
It only lasts a few seconds at a time, is unbelievable loud, very low in
pitch, and sounds just like wind noise on a microphone. Seems to happen at
random times although more common when someone is playing it. Volume
control position has no effect on the noise volume but does sometimes seem
to affect the timbre of the noise. It goes away when you plug headphones in
(you don't hear it in the headphones).
Without the benefit of a service manual/schematic, I have tried to trace the
analog audio signal with an oscilloscope to at least determine from which
stage the noise is coming. I'm suspecting it's originating in the power amp
section - the amps are IC "bricks", one for each channel but since it's in
both speakers equally I'm thinking it's not them. Due to the sheer volume
of the noise it actually loads the power supply to a point where signals at
all stages are affected. I did change the filter cap in the dc supply. No
improvement.
I did read some newsgroup accounts of noise in the Clavinovas being due to
dirty contacts in the volume control... I'm picking up some contact cleaner
today and will try that but I'm not too optimistic about it.
Any experience with this problem or guidance much appreciated.
Mike

[Jeff Liebermann]

On Sun, 25 Sep 2022 11:23:10 -0700 (PDT), Joe Jaramillo

I have the same problem on a C 430. I’ll be playing either quiet or loud and then a hear A rumbling noise that kind of trails off for a bit and then comes back. Did you ever find out what the root cause was?

There's an important clue in the text:
"It goes away when you plug headphones"

My guess(tm) is it's some form of microphonics. That's where the
speakers cause some electribuc component to vibrate, which then causes
audible noises in the speakers. If the gain and phase of the
amplifier is correct, it will produce low frequency feedback, which is
the rumbling noise you hear. If the noise was a high pitched squeal,
then it would be high frequency feedback.

In your case, you have a "C 430". That might be a Yamaha NX-C430
speaker system. The system does not have any built in amplifier(s),
so there's nothing wrong with the speakers. I suggest you remove your
speakers from the amplifier or receiver case, and the microphonics
will likely be reduced or stop.

Incidentally, you're only 19 years too late to catch the original
posters.

I have a Yamaha CLP-411 Clavinova that is about five years old. It has
developed an occasional rumbling sound that comes from both speakers.
It only lasts a few seconds at a time, is unbelievable loud, very low in
pitch, and sounds just like wind noise on a microphone. Seems to happen at
random times although more common when someone is playing it. Volume
control position has no effect on the noise volume but does sometimes seem
to affect the timbre of the noise. It goes away when you plug headphones in
(you don't hear it in the headphones).
Without the benefit of a service manual/schematic, I have tried to trace the
analog audio signal with an oscilloscope to at least determine from which
stage the noise is coming. I'm suspecting it's originating in the power amp
section - the amps are IC "bricks", one for each channel but since it's in
both speakers equally I'm thinking it's not them. Due to the sheer volume
of the noise it actually loads the power supply to a point where signals at
all stages are affected. I did change the filter cap in the dc supply. No
improvement.
I did read some newsgroup accounts of noise in the Clavinovas being due to
dirty contacts in the volume control... I'm picking up some contact cleaner
today and will try that but I'm not too optimistic about it.
Any experience with this problem or guidance much appreciated.
Mike

[legg]

Post by Jeff Liebermann
On Sun, 25 Sep 2022 11:23:10 -0700 (PDT), Joe Jaramillo

I have the same problem on a C 430. I’ll be playing either quiet or loud and then a hear A rumbling noise that kind of trails off for a bit and then comes back. Did you ever find out what the root cause was?

"It goes away when you plug headphones"
My guess(tm) is it's some form of microphonics. That's where the
speakers cause some electribuc component to vibrate, which then causes
audible noises in the speakers. If the gain and phase of the
amplifier is correct, it will produce low frequency feedback, which is
the rumbling noise you hear. If the noise was a high pitched squeal,
then it would be high frequency feedback.
In your case, you have a "C 430". That might be a Yamaha NX-C430
speaker system. The system does not have any built in amplifier(s),
so there's nothing wrong with the speakers. I suggest you remove your
speakers from the amplifier or receiver case, and the microphonics
will likely be reduced or stop.

You might check boards for degrading adhesive employed in tack-on or
harness security, in this case - after the volume control section.

RL

Post by Jeff Liebermann
Incidentally, you're only 19 years too late to catch the original
posters.

I have a Yamaha CLP-411 Clavinova that is about five years old. It has
developed an occasional rumbling sound that comes from both speakers.
It only lasts a few seconds at a time, is unbelievable loud, very low in
pitch, and sounds just like wind noise on a microphone. Seems to happen at
random times although more common when someone is playing it. Volume
control position has no effect on the noise volume but does sometimes seem
to affect the timbre of the noise. It goes away when you plug headphones in
(you don't hear it in the headphones).
Without the benefit of a service manual/schematic, I have tried to trace the
analog audio signal with an oscilloscope to at least determine from which
stage the noise is coming. I'm suspecting it's originating in the power amp
section - the amps are IC "bricks", one for each channel but since it's in
both speakers equally I'm thinking it's not them. Due to the sheer volume
of the noise it actually loads the power supply to a point where signals at
all stages are affected. I did change the filter cap in the dc supply. No
improvement.
I did read some newsgroup accounts of noise in the Clavinovas being due to
dirty contacts in the volume control... I'm picking up some contact cleaner
today and will try that but I'm not too optimistic about it.
Any experience with this problem or guidance much appreciated.
Mike

[Joe Jaramillo]

Post by legg

Post by Jeff Liebermann
On Sun, 25 Sep 2022 11:23:10 -0700 (PDT), Joe Jaramillo

I have the same problem on a C 430. I’ll be playing either quiet or loud and then a hear A rumbling noise that kind of trails off for a bit and then comes back. Did you ever find out what the root cause was?

"It goes away when you plug headphones"
My guess(tm) is it's some form of microphonics. That's where the
speakers cause some electribuc component to vibrate, which then causes
audible noises in the speakers. If the gain and phase of the
amplifier is correct, it will produce low frequency feedback, which is
the rumbling noise you hear. If the noise was a high pitched squeal,
then it would be high frequency feedback.
In your case, you have a "C 430". That might be a Yamaha NX-C430
speaker system. The system does not have any built in amplifier(s),
so there's nothing wrong with the speakers. I suggest you remove your
speakers from the amplifier or receiver case, and the microphonics
will likely be reduced or stop.

You might check boards for degrading adhesive employed in tack-on or
harness security, in this case - after the volume control section.
RL

Post by Jeff Liebermann
Incidentally, you're only 19 years too late to catch the original
posters.

I have a Yamaha CLP-411 Clavinova that is about five years old. It has
developed an occasional rumbling sound that comes from both speakers.
It only lasts a few seconds at a time, is unbelievable loud, very low in
pitch, and sounds just like wind noise on a microphone. Seems to happen at
random times although more common when someone is playing it. Volume
control position has no effect on the noise volume but does sometimes seem
to affect the timbre of the noise. It goes away when you plug headphones in
(you don't hear it in the headphones).
Without the benefit of a service manual/schematic, I have tried to trace the
analog audio signal with an oscilloscope to at least determine from which
stage the noise is coming. I'm suspecting it's originating in the power amp
section - the amps are IC "bricks", one for each channel but since it's in
both speakers equally I'm thinking it's not them. Due to the sheer volume
of the noise it actually loads the power supply to a point where signals at
all stages are affected. I did change the filter cap in the dc supply. No
improvement.
I did read some newsgroup accounts of noise in the Clavinovas being due to
dirty contacts in the volume control... I'm picking up some contact cleaner
today and will try that but I'm not too optimistic about it.
Any experience with this problem or guidance much appreciated.
Mike

[Joe Jaramillo]

I have the same problem on a C 430. I’ll be playing either quiet or loud and then a hear A rumbling noise that kind of trails off for a bit and then comes back. Did you ever find out what the root cause was?

I have a Yamaha CLP-411 Clavinova that is about five years old. It has
developed an occasional rumbling sound that comes from both speakers.
It only lasts a few seconds at a time, is unbelievable loud, very low in
pitch, and sounds just like wind noise on a microphone. Seems to happen at
random times although more common when someone is playing it. Volume
control position has no effect on the noise volume but does sometimes seem
to affect the timbre of the noise. It goes away when you plug headphones in
(you don't hear it in the headphones).
Without the benefit of a service manual/schematic, I have tried to trace the
analog audio signal with an oscilloscope to at least determine from which
stage the noise is coming. I'm suspecting it's originating in the power amp
section - the amps are IC "bricks", one for each channel but since it's in
both speakers equally I'm thinking it's not them. Due to the sheer volume
of the noise it actually loads the power supply to a point where signals at
all stages are affected. I did change the filter cap in the dc supply. No
improvement.
I did read some newsgroup accounts of noise in the Clavinovas being due to
dirty contacts in the volume control... I'm picking up some contact cleaner
today and will try that but I'm not too optimistic about it.
Any experience with this problem or guidance much appreciated.
Mike

Incidentally it also happens with headphones so I’m a bit flummoxed. Oh and btw I have a CLP-440. Next stop Yamaha…

[Samuel Oh]

I have the same problem on a C 430. I’ll be playing either quiet or loud and then a hear A rumbling noise that kind of trails off for a bit and then comes back. Did you ever find out what the root cause was?

I have a Yamaha CLP-411 Clavinova that is about five years old. It has
developed an occasional rumbling sound that comes from both speakers.
It only lasts a few seconds at a time, is unbelievable loud, very low in
pitch, and sounds just like wind noise on a microphone. Seems to happen at
random times although more common when someone is playing it. Volume
control position has no effect on the noise volume but does sometimes seem
to affect the timbre of the noise. It goes away when you plug headphones in
(you don't hear it in the headphones).
Without the benefit of a service manual/schematic, I have tried to trace the
analog audio signal with an oscilloscope to at least determine from which
stage the noise is coming. I'm suspecting it's originating in the power amp
section - the amps are IC "bricks", one for each channel but since it's in
both speakers equally I'm thinking it's not them. Due to the sheer volume
of the noise it actually loads the power supply to a point where signals at
all stages are affected. I did change the filter cap in the dc supply. No
improvement.
I did read some newsgroup accounts of noise in the Clavinovas being due to
dirty contacts in the volume control... I'm picking up some contact cleaner
today and will try that but I'm not too optimistic about it.
Any experience with this problem or guidance much appreciated.
Mike

Incidentally it also happens with headphones so I’m a bit flummoxed. Oh and btw I have a CLP-440. Next stop Yamaha…

Oh damn my church piano developed this issue too a few months ago, and it's been driving me crazy!

[legg]

Post by Samuel Oh

I have the same problem on a C 430. I’ll be playing either quiet or loud and then a hear A rumbling noise that kind of trails off for a bit and then comes back. Did you ever find out what the root cause was?

I have a Yamaha CLP-411 Clavinova that is about five years old. It has
developed an occasional rumbling sound that comes from both speakers.
It only lasts a few seconds at a time, is unbelievable loud, very low in
pitch, and sounds just like wind noise on a microphone. Seems to happen at
random times although more common when someone is playing it. Volume
control position has no effect on the noise volume but does sometimes seem
to affect the timbre of the noise. It goes away when you plug headphones in
(you don't hear it in the headphones).
Without the benefit of a service manual/schematic, I have tried to trace the
analog audio signal with an oscilloscope to at least determine from which
stage the noise is coming. I'm suspecting it's originating in the power amp
section - the amps are IC "bricks", one for each channel but since it's in
both speakers equally I'm thinking it's not them. Due to the sheer volume
of the noise it actually loads the power supply to a point where signals at
all stages are affected. I did change the filter cap in the dc supply. No
improvement.
I did read some newsgroup accounts of noise in the Clavinovas being due to
dirty contacts in the volume control... I'm picking up some contact cleaner
today and will try that but I'm not too optimistic about it.
Any experience with this problem or guidance much appreciated.
Mike

Incidentally it also happens with headphones so I’m a bit flummoxed. Oh and btw I have a CLP-440. Next stop Yamaha…

Oh damn my church piano developed this issue too a few months ago, and it's been driving me crazy!

Check for degraded adhesive used on pcb assys for vibration
defense.

Remove it and clean the area with alcohol, anywhere it comes
into contact with board traces or connector terminals.

RL