I have observed lately that the sound on my MOXF8 has changed for worse. It starts OK but after a while it becomes...tinny. It so obvious when playing any organs sounds that all depth is completely lost but there is no distortion. I have just measured the voltage on the power supply unit and it shows 12.2V (perhaps under load it would show less). The power supply unit is not Yamaha made but it was supplied with the keyboard by Yamaha when purchased (new) here in Australia. Is my MOXF8 on the way out? Everything still works but this sound issue is a worry. I do have a flash memory module installed and I am not sure if the data on it can affect the unit in some way over time (data corruption etc). I have not put anything on it in three years.

Click thumbnail to see full-size image

Before getting too deeply into diagnosis…
What are you listening on? If speakers, disconnect all cables at the MOXF except power, plug a pair of headphones into the PHONES jack, and see whether the change in audio quality still occurs. If so, is the change sudden or gradual?

Thank you 5pinDIN. This instrument is used daily in house only. Most of time I use https://images.app.goo.gl/PHPFKuUofBbDWMYv9 headphones. I have better headphones but these give me the best sound (this is my second pair). I have active studio monitor speakers connected but they are switched off. The sound changes gradually I would say and only when it becomes completely tinny I notice it. I can also report that it sounds bad occasionally as soon as I switch the keyboard on. It is just lacking the deep frequencies and everything is kind of in middle (like AM radio). Is there a way to measure the voltage under load perhaps? I am reluctant to do a hard reset because I am not sure what will happen to the memory module and my custom settings etc.

cajo - 17 August 2020 12:35 AM

Thank you 5pinDIN.

You’re welcome.

 

cajo -

This instrument is used daily in house only. Most of time I use https://images.app.goo.gl/PHPFKuUofBbDWMYv9 headphones. I have better headphones but these give me the best sound (this is my second pair). I have active studio monitor speakers connected but they are switched off. The sound changes gradually I would say and only when it becomes completely tinny I notice it. I can also report that it sounds bad occasionally as soon as I switch the keyboard on. It is just lacking the deep frequencies and everything is kind of in middle (like AM radio).

I suggest turning on the speakers and determine whether the sound is normal or not with them.

What you’re hearing with headphones may be related to the headphones themselves. There’s a problem that can develop, although people describe the sound somewhat differently.
See these threads:
http://motifator.com/index.php/forum/viewthread/474599
http://motifator.com/index.php/forum/viewthread/481355
http://motifator.com/index.php/forum/viewthread/479531
http://motifator.com/index.php/forum/viewthread/481675

 

cajo -

Is there a way to measure the voltage under load perhaps?

Yes. The original Yamaha PA150 power adapter is rated for 1.5 amps - an 8 ohm resistor (should be rated for at least 20 watts, due to required heat dissipation) would draw that much current at 12 volts. However, your adapter appears to be rated for more current, so a #1156 automotive light bulb, which draws about 2 amps at 12 volts, could be used as a load. (Note: A PA150 should not be tested with that bulb, since the current draw would exceed the adapter’s ratings.)

 

cajo -

I am reluctant to do a hard reset because I am not sure what will happen to the memory module and my custom settings etc.

A factory reset won’t affect the flash module contents. If you save an “All” file, you could load it to restore your personal settings after a reset.

However, before doing a reset or even measuring the power adapter output voltage, I suggest listening on speakers and looking into possible headphone issues, as above.