Coil whine/high pitched noise

N

nørholm

Member
Hi,
I had to return my fm9 because of a high pitched noise that came from the unit itself (even when nothing is plugged in) - sounded like a coil whine. I found out that it was connected to the brightness of the LEDs… it went away when I turned the brightness to zero… but thats obviously not an option. I received a replacement unit today - same thing. I‘ve tried it in different room, in my studio… same thing. I find it really disturbing in a quiet studio environment, because it‘s like having a Tinitus sound in your head. It also bleeds into the pickups when closer to the unit, for example when operating it on the desk. Do all fm9 pedals have this behaviour, or am I just extremely unlucky?
 
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By the way… I‘m not new to the fractal world - been using fractal stuff since the axe-fx ultra, so it‘s not user error or something. Had an fm3 mkII - this device was dead quiet. Even did a comparison on the same power outlet, placing it next to the fm9. Fm3 silent, fm9 was whining…. :(
 
Could be the fan controller... When restarting the unit and waiting a while, the noise is usually gone. After rebooting, it takes maybe 2-3 minutes and the noise comes back. Seems to be a power thing, as it's still depending on the led brightness as well. Don't know if the fan speed and led brightness are somehow on the same "power grid"... The noise is also pulsing in the tempo of the tap led. Is there a way to change the fan controller settings, to see if that changes anything...
 
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I would try using an isolated power supply or briefly try a ground lift [I would not use the unit this way but just as a test]
 
it is not a grounding problem. The noise comes from the unit itself - even when nothing else is plugged in - except for power. My outlets are proper grounded, and as mentioned, the fm3 was dead quiet in the same setup. It‘s hard to locate the noise… I can hear it when loudest when placing my ears over the right top corner of the display, and also at the fan. I guess it could be the fan beeing in an „idle“ state - receiving some power, but not enough to turn. But why it is also dependent on the led brightness, I don‘t know, except for maybe the fan controller is somehow connected to the power supply section of the leds.
 
This is odd, I think this is the first time I’ve seen this reported. First thought was that you were hearing the fan, but you say is goes away when you turn down the LED level.

Is this whine coming through your monitoring or from the unit itself?

If it’s through your monitoring does it increase in volume as you turn up the output? How are you monitoring? Try a different method (speakers vs headphones etc). Does the whine come from all outputs?

Let’s try to narrow this down.
 
As already mentioned - it has nothing to to with the monitoring or what the fm9 is connected to. The noise is a noise coming from the physical hardware (fm9) itself.
BUT it does "bleed" into the pickups when operating close to the unit - like having it infront of you on a desk. And then, of course the high pitched noise is amplified thru the outputs.
 
nørholm said:
As already mentioned - it has nothing to to with the monitoring or what the fm9 is connected to. The noise is a noise coming from the physical hardware (fm9) itself.
BUT it does "bleed" into the pickups when operating close to the unit - like having it infront of you on a desk. And then, of course the high pitched noise is amplified thru the outputs.
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This does sound like it’s the fan… I think your best option is to reach out to support again, they will do their best to figure this out. You could also ask them if they were able to reproduce it with the returned unit.

Sorry you are having this issue, I’d be pretty bummed too.
 
I made a short clip - easier to hear when using headphones, as my camera mic did not pickup the sound as good and it's not the quietest Environment right now... it's way more noticable in the room. But you can tell that the noise goes away when turning off the leds...
 
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Does it make any difference if you change either the AD/Sensitivity or Input Gain levels under Setup -> Input Levels?
 
It has nothing to do with signal levels... nothing is plugged in to the device, except for the IEC power cable. The noise is coming from the fm9. I made a better video where its easier to hear. I had the fm9 turned off for some hours. I turned it on, it worked perfectly for about 7 minutes, the it startet to whine again as show in the clip:

 
ok. but is it supposed to whine like that? it doesn‘t sound as if it‘s moving. When turning the unit on, the fan turns on, and you can hear it blowing air… but that coil whine sound is different. Any idea how to solve the problem? It‘s really quite anoying in a studio environment :/
 
nørholm said:
ok. but is it supposed to whine like that? it doesn‘t sound as if it‘s moving. When turning the unit on, the fan turns on, and you can hear it blowing air… but that coil whine sound is different. Any idea how to solve the problem? It‘s really quite anoying in a studio environment :/
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It does sound like an issue with the unit itself, in which cas sending it in and getting a new one under warranty would be the best solution, no?

Sorry im a dummy, you already went through that process. Thats very peculiar and kind of annoying that no one is seemingly trying to help besides guessing at what might be causing this, or just saying "its the fan 🤷‍♂️". I do acknowledge that there could be DMs and emails trying to get to the bottom of it, but then why would this be posted here at all? My unit doesnt do that. I assume you are in a temperature controlled environment (you mentioned being in a studio, or at the very least indoors).
 
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yeah, don‘t really know what to do… if it‘s just the fan, then replacing it with another one (noctua?) would be way easier than shipping the unit back and forth a second time. Video was made at home… 20 degrees C indoor temp. Also tried it at the studio - same thing. I‘ll do some more tests… it seems to start to „whine“ when the enclosure temp of the fm9 reaches around 38 degrees C… the fan still doesn‘t move at this point, but the noise appears. I think it maybe has something to do with the pwm controller… maybe thats why it also reacts to the LEDs beeing dimmed?
Is warranty void when opening the unit and replacing the fan myself? Or maybe just disconnecting it first for a second, to see if the whine goes away?
 
Maybe in the mean time you can have a silent (PC) fan blow on it somewhere to check if that would prevent any of it...
 
FractalAudio said:
It's the fan. It turns on when the internal temperature exceeds a threshold.
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but the fan doesn‘t turn on… it turns on for a short while when rebooting the fm9… after that it doen’t turn on. Also the temperatures aren‘t high in the unit. But after about 5 minutes, the whining starts, and only goes away when I turn the LEDs brightness to 0%. The fan has never turned on, except for when rebooting.
 
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