Amp will also be triggered if I turn fan on. How to fix?

[veeceem]

So I have a fan in the room, the amp is NAD M22 vs driven by Topping DX7 pro
I have the amp set to auto turn on whenever it detects signal from the Pre.
Strange behavior is that whenever I turn the fan on, the amp will also be triggered and turned on. (I also notice the TV will sometimes turn itself on/off (but not always) for a short period when I turn light on/off)

What could've caused the amp to turn itself on? Will this be dangerous to the amp in any way? Is there a way to fix this? I'm lost and looking for advices. Thanks in advance!

 

[threni]

Sounds like perfectly ordinary paranormal activity.

 

[tadawson]

Variable speed fan? Likely a very noisy speed controller . . .

 

[veeceem]

Variable speed fan? Likely a very noisy speed controller . . .

Yes, variable speed fan

 

[Chrispy]

Do you turn on the fan remotely or manually? Never thought about a wall mount fan like that....but the floor stander I use I use a remote with.

 

[veeceem]

manually. I wonder if (?) EMI from the speed controller is the cause of this behavior and should the ferrite bead fix this? :|

 

[Chrispy]

manually. I wonder if (?) EMI from the speed controller is the cause of this behavior and should the ferrite bead fix this? :|

What else could it be? Don't know if ferrites would help...

 

[Chrispy]

....or just turn that auto on feature off....

 

[egellings]

Try a surge protector between the fan and its power outlet. These are extension cords with an outlet box on one end, and the box has the surge components (often a MOV) in it. The protectors block surges in both direction, and I think a switching transient from using the fan's switch is doing that. I bet that fixes your problem. Another way would be to use an RC snubber at the switch itself. That would require a technician to install.

 

[veeceem]

....or just turn that auto on feature off....

can't cuz I put it out of sight

 

[veeceem]

Try a surge protector between the fan and its power outlet. These are extension cords with an outlet box on one end, and the box has the surge components (often a MOV) in it. The protectors block surges in both direction, and I think a switching transient from using the fan's switch is doing that. I bet that fixes your problem. Another way would be to use an RC snubber at the switch itself. That would require a technician to install.

Thanks, I'll look into this idea and give it a try!

 

[Chrispy]

can't cuz I put it out of sight

Other ways to do auto on, like a smart power strip.....

 

[AnalogSteph]

OP, what sort of connection are you using between the DX7 Pro and M22? Can you hear a pop sound through the speakers when turning the fan on? Is there anything unusual about your electrical system, like lack of (properly) earthed outlets? (Even then, plugging the DAC and amp into the same power strip should suffice.)

In the simplest of all cases you're currently using RCA cables, then you'd simply have to swap these out for some decent XLRs. Otherwise some more investigation will be required...

 

[MakeMineVinyl]

WIth 'auto on/off' circuits on our class "D" amplifiers, the input section of the amplifier is always ON, and after a timeout with no signal above a certain threshold, the class "D" module's enable is turned OFF. A transient signal like a pop from a fan control could be sensed on the amp's input and trigger the amp ON.

Your problem is undoubtedly coming from the fan as a transient which is being picked up by the amplifier. I don't know what would fix this beyond a ferrite clipped around the fan's AC cable.

 

[veeceem]

OP, what sort of connection are you using between the DX7 Pro and M22? Can you hear a pop sound through the speakers when turning the fan on? Is there anything unusual about your electrical system, like lack of (properly) earthed outlets? (Even then, plugging the DAC and amp into the same power strip should suffice.)

In the simplest of all cases you're currently using RCA cables, then you'd simply have to swap these out for some decent XLRs. Otherwise some more investigation will be required...

PC -> USB cable -> DX7 Pro -> Canare L-4e6s XLR cable -> NAD M22v2 amp
All on same outlet, no earthed ( no 3rd prong). No thing unusual (such as pop on speakers, ect...) Just that the amp turn itself on.
Normal behavior should be: The DX7 pro does turn itself on if itself on if I turn on computer, then the amp turn itself on if it detects "sound signal" being played.
The normal behavior still true. But what puzzles me is that the amp also turn itself on if I turn the fan on or change fan's speed. This is not always, but will happen once every few times :/
From my observation: dx7 pro's LED panel wont turn on in this case.

 

[AnalogSteph]

No thing unusual (such as pop on speakers, ect...) Just that the amp turn itself on.

So to clarify: If the amplifier is already running (but DAC is off) and you then turn the fan on, there is nothing to be heard in the speakers?

 

[veeceem]

So to clarify: If the amplifier is already running (but DAC is off) and you then turn the fan on, there is nothing to be heard in the speakers?

Yes, nothing "unusual" from computer / speaker. Only the amp turns itself on when fan on/change fan speed.

 

[AnalogSteph]

Huh.

Bit of a headscratcher, this. I would be inclined to consult with NAD support (prividing all the info you have here), maybe they've got another idea. It seems hard to imagine that the signal detection circuitry would be sensitive to ground currents when the amplifier itself is not, but that's almost what it looks like.

 

[MakeMineVinyl]

Huh.

Bit of a headscratcher, this. I would be inclined to consult with NAD support (prividing all the info you have here), maybe they've got another idea. It seems hard to imagine that the signal detection circuitry would be sensitive to ground currents when the amplifier itself is not, but that's almost what it looks like.

If the NAD auto-trigger is anything similar to ours, it only takes around 9mV to trigger any one input to turn on; a disturbance on all channels would lower the total required below any one channel. There's only so many ways to design this kind of circuit, so I would imagine the simplest explanation is probably the most probable. At least in our implementation, the trigger is designed to turn on as fast as possible so that no audio signal is clipped off at its beginning. Also, the auto-on circuitry can be defeated if customers find it problematic; the NAD might have a similar functionality.