Radio interference (FM) and buzzing in speakers without input source

[aerochrome2]

Hello everyone!

After much anticipation, I finally set up my new KEF Q150s today with my new Cambridge Audio AXA25 for a budget nearfield listening setup.

Unfortunately, I am getting MASSIVE radio interference even before plugging an input source into the system where the speakers basically play the radio. Some other details are below, but you can clearly hear it is playing "Hot 99.5 FM"; WIHT. I googled it and It just so happens I live somewhere close to the antenna (Wikipedia says it is on a main road right by my house; I can't find the exact location but if I had to guess, I would guess about a mile or two).

A few other clues: (1) input selection doesn't matter; (2) turning the amps volume knob does not do a ton; (3) it is much worse in one speaker (the right) and turning the balance knob to the right makes it much louder; (4) moving the right speaker directly next to the left speaker doesn't change that much (the right is still worse); and (5) I have not had problems using active speakers in the same exact location (KEF Eggs).

I am looking for the simplest way to fix this without spending a ton of additional time or energy. Would shielded speaker wire fix the issue? A better designed amp? Both?

THANKS - this was not what I was hoping for my first hifi system!

 

[RayDunzl]

Unfortunately, I am getting MASSIVE radio interference even before plugging an input source into the system where the speakers basically play the radio. Some other details are below, but you can clearly hear it is playing "Hot 99.5 FM"; WIHT. I googled it and It just so happens I live somewhere close to the antenna (Wikipedia says it is on a main road right by my house; I can't find the exact location but if I had to guess, I would guess about a mile or two).

https://radio-locator.com/info/WIHT-FM

https://www.google.com/maps/@38.964...EpKikvB-p8UHqqxlo1aw!2e0!7i13312!8i6656?hl=en

 

[Inner Space]

My experience - I lived in an apartment eleven blocks south of the Empire State Building which at the time had 400 transmitters on it, in direct line of sight out my window. I had dozens of amps in and out (because I was trying to learn headphones, because apartment) and all were silent except one, which acted just like yours. Not obviously badly designed, not the cheapest, one of the most respected. Just random bad luck. Change the amp.

 

[Doodski]

I had a similar issue where the stereo was picking up aircraft radio chatter. It would cut in loud and clear intermittently. I never found a solution. I replaced the old Sears amplifier with a new Technics and the issue stopped occurring. Do you have another amp to test?

 

[Berwhale]

Are your speaker cables the same length? What is your source?

 

[aerochrome2]

My experience - I lived in an apartment eleven blocks south of the Empire State Building which at the time had 400 transmitters on it, in direct line of sight out my window. I had dozens of amps in and out (because I was trying to learn headphones, because apartment) and all were silent except one, which acted just like yours. Not obviously badly designed, not the cheapest, one of the most respected. Just random bad luck. Change the amp.

Thanks - I definitely don't want to drive myself crazy troubleshooting, so may give that a shot!

https://radio-locator.com/info/WIHT-FM

https://www.google.com/maps/@38.964...EpKikvB-p8UHqqxlo1aw!2e0!7i13312!8i6656?hl=en

Thanks, a little less than a mile! I am hopeful that this doesn't rule out setting up a system, but based on the post below, I may start by trying another amp.

 

[aerochrome2]

Are your speaker cables the same length? What is your source?

Speaker cables are https://www.crutchfield.com/p_007CBB10/Crutchfield-Speaker-Wire-10-feet.html (x2).

I also bought Belden 5000UE 12 AWG (unterminated) to run into the speaker level input of my subwoofer (NOT plugged in right now). If that has a chance of being better, I could test it out.

Source will be an SMSL M500 DAC, but in all of this testing, I did not have it plugged in. I did have it plugged in just to test it worked (which it did), but I couldn't listen long with the awful loud humming.

 

[RayDunzl]

As an experiment:

You might try re-orienting the integrated... rotate, stand on end and rotate, whatever... since it is acting as an antenna, just to see if things change...

 

[aerochrome2]

As an experiment:

You might try re-orienting the integrated... rotate, stand on end and rotate, whatever... since it is acting as an antenna, just to see if things change...

If I move it within a five to seven for radius, it definitely changes how loud/clear I get the radio signal, but is still always loud. My speaker cables aren't long enough to do take the experiment further.

 

[RayDunzl]

Assuming the speaker cables are creating a problem...

The Belden 5000UE is a twisted pair (good).

What speaker cables are you using now?

How long are the speaker cables?

"If you're trying to tune into FM radio (85Mhz - 99.5Mhz) you're looking at about 10 total feet of antenna length for the best signal."

That doesn't sound right, but gives another clue.

Maybe try very short length, or move the speaker right next to the amp and coil the cable to break the antenna, one speaker only connected.

 

[aerochrome2]

Assuming the speaker cables are creating a problem...

The Belden 5000UE is a twisted pair (good).

What speaker cables are you using now?

How long are the speaker cables?

"If you're trying to tune into FM radio (85Mhz - 99.5Mhz) you're looking at about 10 total feet of antenna length for the best signal."

That doesn't sound right, but gives another clue.

Maybe try very short length, or move the speaker right next to the amp and coil the cable to break the antenna, one speaker only connected.

I was using the Crutchfield (10ft), but just switched to the Beldens (15ft) as an experiment. No improvement.

I just tried to disconnect the left speaker, bring the right next to the amp and coiled the Belden cable. No improvement.

It is looking like it may be the amp after all? One other note about the amp - it uses a polarized plug (not a grounded plug). I do not see a grounding screw anywhere. Could it be a grounding issue?

 

[Doodski]

I was using the Crutchfield (10ft), but just switched to the Beldens (15ft) as an experiment. No improvement.

I just tried to disconnect the left speaker, bring the right next to the amp and coiled the Belden cable. No improvement.

It is looking like it may be the amp after all?

Yes, it appears the amp is picking up RF.

 

[RayDunzl]

Can the amp be returned as unusable?

 

[aerochrome2]

Can the amp be returned as unusable?

Yeah - I already have a return authorization from Cambridge (shipped directly from them).

I spent a lot of time researching that amp! I may try the Emotiva BasX A-100 although it doesn't seem to blow anyone away. I could also try upgrading to the A-300 or even the NAD NAD C316BEE V2.

 

[Doodski]

Yeah - I already have a return authorization from Cambridge (shipped directly from them).

I spent a lot of time researching that amp! I may try the Emotiva BasX A-100 although it doesn't seem to blow anyone away. I could also try upgrading to the A-300 or even the NAD NAD C316BEE V2.

I would go for the NAD NAD C316BEE V2. It has bass and treble controls, headphone jack and multiple inputs.

 

[aerochrome2]

I would go for the NAD NAD C316BEE V2. It has bass and treble controls, headphone jack and multiple inputs.

Thanks! I need to think on it. I would have loved to stay in the $250-$350 range, but I may be out of luck.

 

[pma]

The cure is a JFET input stage, good shielded case and the design rules with respect to EMI. Unfortunately, consumer audio producers do not care so the result is just random.

 

[aerochrome2]

Before I swap out the amp, is it worth trying a ferrite bead / choke on the power cable and/or speaker wires?

 

[LTig]

Does the Cambridge Audio has a CE lable? Is there any document which says that the unit adheres to any safety standards?

 

[Doodski]

Before I swap out the amp, is it worth trying a ferrite bead / choke on the power cable and/or speaker wires?

No, a ferrite bead will not improve the situation. Ferrite beads are generally used to block digital noise from going into the electrical system in your home. RF noise is totally different.