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

[aerochrome2]

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

From the manual:

CE MARK
This product complies with European Low Voltage (2014/35/EU), Electromagnetic Compatibility (2014/30/EU) and Environmentally-friendly design of Energy-related Products (2009/125/EC) Directives when used and installed according to this instruction manual. For continued compliance only Cambridge Audio accessories should be used with this product and servicing must be referred to qualified service personnel.

 

[aerochrome2]

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.

Thanks! I am just going to try the emotiva and will report back in about a week when I get it.

 

[LTig]

From the manual:

CE MARK
This product complies with European Low Voltage (2014/35/EU), Electromagnetic Compatibility (2014/30/EU) and Environmentally-friendly design of Energy-related Products (2009/125/EC) Directives when used and installed according to this instruction manual. For continued compliance only Cambridge Audio accessories should be used with this product and servicing must be referred to qualified service personnel.

Well, then it seems that it's not really compliant to Electromagnetic Compatibility (2014/30/EU):

The electromagnetic compatibility (EMC) Directive 2014/30/EU ensures that electrical and electronic equipment does not generate, or is not affected by, electromagnetic disturbance.​

I have no clue what the specs are which a CE compatible amplifier needs to fulfill though.

 

[aerochrome2]

Well, then it seems that it's not really compliant to Electromagnetic Compatibility (2014/30/EU):

The electromagnetic compatibility (EMC) Directive 2014/30/EU ensures that electrical and electronic equipment does not generate, or is not affected by, electromagnetic disturbance.​

I have no clue what the specs are which a CE compatible amplifier needs to fulfill though.

Very interesting!

 

[Berwhale]

Well, then it seems that it's not really compliant to Electromagnetic Compatibility (2014/30/EU):

The electromagnetic compatibility (EMC) Directive 2014/30/EU ensures that electrical and electronic equipment does not generate, or is not affected by, electromagnetic disturbance.​

I have no clue what the specs are which a CE compatible amplifier needs to fulfill though.

I wonder if Hot 99.5 FM's massive radio transmiter is also compliant with European regulatory requirements?

 

[BDWoody]

Thanks! I am just going to try the emotiva and will report back in about a week when I get it.

What a drag! I hope the new amp works out better...

 

[somebodyelse]

Well, then it seems that it's not really compliant to Electromagnetic Compatibility (2014/30/EU):

The electromagnetic compatibility (EMC) Directive 2014/30/EU ensures that electrical and electronic equipment does not generate, or is not affected by, electromagnetic disturbance.​

I have no clue what the specs are which a CE compatible amplifier needs to fulfill though.

From memory the details are quite prescriptive in some areas and open to interpretation in others, which often means a standard has been written to accommodate the current practice of everyone who's got to agree to it. 'Still working, but with a slightly degraded noise performance when close to a powerful radio transmitter' is probably ok by the letter of the rules - even if the 'noise' is understandable as the local radio station or taxi company.

 

[KSTR]

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.

One simple brute-force band-aid one can aways try is using a lot of clamp-on ferrites on just any cable in the system.

And, @Doodski, ferrites really can be effective exactly for taming RF interference, though not for all types of it, it only fixes common-mode problems (which IME are the bulk of the problem).

 

[raindance]

Get another amp. Simple. You can always buy used if your budget is small.

 

[Raindog123]

I would contact the radio station and make their technicians to fix your issue (I mean on your side, not on theirs.) Or to offer you a lucrative compensation... I do not think this is fair/normal situation.

 

[aerochrome2]

The Emotiva arrived this afternoon; so far, so good! No hint of any RFI and sounds great.

Can't wait to break the system in a bit. Thanks for all your help guys.

 

[Doodski]

Good StuFF!!! Glad to hear it.

 

[LTig]

The Emotiva arrived this afternoon; so far, so good! No hint of any RFI and sounds great.

Can't wait to break the system in a bit. Thanks for all your help guys.

Very good. No need though to break anything in - just start enjoying right now.

 

[spacebar]

I’m glad it worked out aerochrome ... but this issue got me curious about why the CA Axa25 have this problem but not the emotiva. Found an image from the inside of the Cambridge audio axa25, can someone tell by the design that it might pick up interference? It’s probably more to it, but I find this very interesting

 

[Robesini]

If you are on a small budget you can also get some nice amplifiers from the secondhand market stores. I bought a Harman Kardon HK970. It needed some servicing. 4 new 12000uF capicators. The usual bias adjustment. But it does not play radio stations and sounds awesome. The complete set was 150 euro for the HK970 amplifier, HD970 cd and TU970 tuner. I use Chairo Hiper 1000 speakers, small speakers with a decent sound. The complete set is more than 15 years old. Please note something changed with the HarmanKardon brand some years ago. I can recommend the older equipment not what you can get in the store nowadays. I changed the amplifier once with a Pioneer Class D amplifier. Plenty of power and sounds clear but not very smooth so back again to this one. I hope it will never break down.

 

[Robesini]

I also have the Harman/Kardon 970 set limited edition with complete black fronts. After a recap, some strugles to get the bios right this realy sounds very good. I even question if a torial tranformer makes a difference in amplifiers. I think this amplifier should be measured it certainly must be one of the best on the second hand market.

 

[fpitas]

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

A bead might help.