Question about EMI and how to get rid of it

[detex1]

Hello,

I have a speaker (Fender FR-10) and I'm noticing some digital noise (kinda sounds like digital morse code, I uploaded a sound clip here).

The speaker is connected directly to a (probably poorly) grounded outlet, and the noise is present even with only the power cable plugged in.

I have noticed that my microphone (hooked up to an audio interface connected to PC) also has the exact same noise in the signal.

What is this noise and how do I get rid of it?

My house is very old so I'm pretty sure the wiring isn't good.

Will a power conditioner solve this issue, and if so are there any recommendations?

Thank you

 

[Apesbrain]

The noise is there with no sources connected, only power?

Try turning off any other devices on the same circuit, or even on other circuits. Might be caused by 2.4 GHz wireless phone or similar device. Or by a light fixture or rheostat. Old cellular devices can also cause noise like this.

 

[Roland68]

Hello,

I have a speaker (Fender FR-10) and I'm noticing some digital noise (kinda sounds like digital morse code, I uploaded a sound clip here).

The speaker is connected directly to a (probably poorly) grounded outlet, and the noise is present even with only the power cable plugged in.

I have noticed that my microphone (hooked up to an audio interface connected to PC) also has the exact same noise in the signal.

What is this noise and how do I get rid of it?

My house is very old so I'm pretty sure the wiring isn't good.

Will a power conditioner solve this issue, and if so are there any recommendations?

Thank you

It makes more sense to find the source of the problem first.
I would switch everything off briefly, including the PC, refrigerator, and heating system, and also unplug all other power supplies.
Once the problem disappears, switch everything back on one by one and note when it reappears.

Is there a difference between during the day and late at night?

 

[detex1]

The noise is there with no sources connected, only power?

Try turning off any other devices on the same circuit, or even on other circuits. Might be caused by 2.4 GHz wireless phone or similar device. Or by a light fixture or rheostat. Old cellular devices can also cause noise like this.

Yes, only power cable is plugged in - nothing else.

I have definitely tried turning off everything in this room, I guess I will have to start unplugging everything assuming it is coming from inside the house?

I should mention that the power cable from the electric company is basically hooked up to the outside of this room.

 

[detex1]

It makes more sense to find the source of the problem first.
I would switch everything off briefly, including the PC, refrigerator, and heating system, and also unplug all other power supplies.
Once the problem disappears, switch everything back on one by one and note when it reappears.

Is there a difference between during the day and late at night?

The noise floor is definitely louder at night with more buzz and hum but its not a huge deal as its still pretty quiet compared to the digital beeping.

The amount of beeping appears to be the same.

 

[Cbdb2]

Yes, only power cable is plugged in - nothing else.

I have definitely tried turning off everything in this room, I guess I will have to start unplugging everything assuming it is coming from inside the house?

I should mention that the power cable from the electric company is basically hooked up to the outside of this room.

Your power circuit may power more than one room. The power into the house has to go to a breaker (fuse) panel before getting to that room.

 

[WXfreak]

Any cellphone towers outside? Have you turned off your WiFi router?

 

[Cbdb2]

First, this is a guitar amp with 1000 watt amp thats suppossed to be used with a modeling pedal. The amp will have a lot of gain. If it has a high impedance input that would help it pick up airborne EMI thru the input. Is the input shorted? Do you hear the noise with the volume turned off?

 

[detex1]

Any cellphone towers outside? Have you turned off your WiFi router?

There is one on top of an apartment complex across the street - about 90m away from my house.

No I haven't turned off my router but I will as soon as I can (people are home).

 

[detex1]

First, this is a guitar amp with 1000 watt amp thats suppossed to be used with a modeling pedal. The amp will have a lot of gain. If it has a high impedance input that would help it pick up airborne EMI thru the input. Is the input shorted? Do you hear the noise with the volume turned off?

Yes the noise appears to be the same and independent of the volume knob.
If I turned the volume knob to zero, its still there.

I'm not sure what you mean by shorted input.. sorry

 

[xanalog]

So, you have nothing connected to your active Fender FR-10s but you still hear noise.
The FR10s are equipped with a three-prong AC powerline connector.
Can you please put a cheater plug on it and see if the noise goes away?
Leaving the input connections unterminated may also cause this problem.


ADD: I listened to your soundclip and definitely is not AC/60Hz related.

 

[Cbdb2]

Yes the noise appears to be the same and independent of the volume knob.
If I turned the volume knob to zero, its still there.

I'm not sure what you mean by shorted input.. sorry

Shorted input means a wire across the input + and ground (or + and - if balanced) which should get rid of any EMI picked up by the input. But if your volume makes no difference than that probably wont matter. Does turning the amp 90 degrees make a diff? does plugging it in on the other side of the house?

 

[Cbdb2]

So, you have nothing connected to your active Fender FR-10s but you still hear noise.
The FR10s are equipped with a three-prong AC powerline connector.
Can you please put a cheater plug on it and see if the noise goes away.

Whats a cheaper plug? You mean a ground lift? That is something to try just to see if it makes a diff. But NEVER use the amp with a ground lift.!!!

 

[xanalog]

[1]Whats a cheap[t]er plug? You mean a ground lift?
[2]That is something to try just to see if it makes a diff. But NEVER use the amp with a ground lift.!!!

[1] Yes
[2] Maybe your 3rd AC wire (AC Protective) is not a good ground (old house).

 

[xanalog]

There is a trove of information about noise with these FR-10s that is discussed in the following link.

Fender FR-10
I'm tempted to crack mine open and see if there're any obvious grounding problems at play. It does seem to be a widespread issue.

From <https://thegearforum.com/threads/fe...0-and-fr-12-frfr-cabs.3351/page-6#post-123953>

 

[detex1]

There is a trove of information about noise with these FR-10s that is discussed in the following link.

From <https://thegearforum.com/threads/fe...0-and-fr-12-frfr-cabs.3351/page-6#post-123953>

It looks like someone took it apart and looked at the wiring and found it to be fine: https://thegearforum.com/threads/fender-tone-master-fr-10-and-fr-12-frfr-cabs.3351/post-124324

I did see posts about the Fender FRFR cabs but they seem to mention humming, buzzing, or hissing, which apparently were present on early production models. Mine is a later model for sure.

 

[detex1]

So, you have nothing connected to your active Fender FR-10s but you still hear noise.
The FR10s are equipped with a three-prong AC powerline connector.
Can you please put a cheater plug on it and see if the noise goes away?
Leaving the input connections unterminated may also cause this problem.


ADD: I listened to your soundclip and definitely is not AC/60Hz related.

The noise is present whether the input cables are connected or not. There is an unconnected output jack but I'm assuming that's irrelevant?

Turning up the cut knob does get rid of it but that also gets rid of some of the frequency of the signal too..

 

[Sokel]

The spectrum may help:

looks like there's something very wrong, all over.
Are there any motors around there running at 1000-2000 rpm? Like fan or something?

Also, some ground issues for sure.

 

[Speedskater]

Take it to a friends place in a different neighborhood.
What kind of signal input: RCA, XLR or digital?

 

[Peterinvan]

I plugged a grounding wire into my AC socket, and wrapped it around my RCA plug. This solved my HUM issue.

CAUTION: careful with AC sockets!!!!