Hissing Noise at High Volumes with Cambridge Audio Azur 651A

[hybridauth_Facebook_10204860956785508]

Problem: At high volume levels I am experiencing a mild "hissing" static noise. I am playing the music from my Macbook Pro to the Azur651A via USB cable. The Azur is connected to a pair of B&W DM602 s3. The noise starts when the USB is plugged in at around 60% volume with no music playing.

What I have tried: If I unplug the USB from the Azur then the noise stops entirely. If I change the source to any unused source then the noise is not there. I have made certain the leads are not switched on either the speakers or amp (positive vs. ground). I have tried using different USB chords (shorter vs longer). I have checked all connections.

Conclusions:

USB cable is picking up noise

Amp is no good

Equipment:

Azur 651A amp

B&W DM602s3 speakers

2015 macbook pro

USB 10 ft A to B

 

[Covenanter]

Problem: At high volume levels I am experiencing a mild "hissing" static noise. I am playing the music from my Macbook Pro to the Azur651A via USB cable. The Azur is connected to a pair of B&W DM602 s3. The noise starts when the USB is plugged in at around 60% volume with no music playing.

What I have tried: If I unplug the USB from the Azur then the noise stops entirely. If I change the source to any unused source then the noise is not there. I have made certain the leads are not switched on either the speakers or amp (positive vs. ground). I have tried using different USB chords (shorter vs longer). I have checked all connections.

Conclusions:

USB cable is picking up noise

Amp is no good

Equipment:

Azur 651A amp

B&W DM602s3 speakers

2015 macbook pro

USB 10 ft A to B

Your evidence points to a very different conclusion which is that the hiss is being generated by the Macbook!

Chris

 

[philpot1001]

I agree with Covenanter that at least the Macbook should be among the possible culprits - how have you discounted it as a source of the noise? I would say its unlikely the amp if its quiet with all other sources (*caveat - its possible something has come loose in the amp at the USB connection).

Best way to check is use another digital source (maybe an iphone or something, you will obvs need to use the dedicated phone USB for that) and see if the noise persits. If not - its your Mac / USB cable.

 

[Blackdawn]

USB connections are noisy. Best to use Coaxial or Optical to your DAC. Asynchronous USB DAC's are better than non asynchronous USB DAC's

 

[philpot1001]

USB connections are noisy. Best to use Coaxial or Optical to your DAC. Asynchronous USB DAC's are better than non asynchronous USB DAC's

Is there an optical or coaxial output on a Macbook? I genuinely dont know as i dont have one, but my laptop certainly doesnt have that functionality.

 

[davedotco]

Noise can be a problem with usb, but better dacs should be able to reject this, if you have a 'tame' dealer, see if you can borrow a usb dac to try.

Even better, get a dac with spdif inputs too, try the optical input on the Macbook.

Edit. Macbooks usually have a mini toslink combined with the headphone output but the 651A is usb only.

 

[Deleted member 116933]

Have you tried using a USB cable with a Ferrite Core Noise Suppressor on it. Its what there designed for. Its a cheap fix that might work

they look like this

http://www.aliexpress.com/store/product/5pcs-pack-Movable-Offset-5mm-Clip-On-Cable-EMI-RFI-Filter-Snap-Around-Ferrite-Core/931762_2053183158.html

 

[hybridauth_Facebook_10204860956785508]

Thanks! The usb I have is a A to B connection. Do they have opticals for those?

 

[hybridauth_Facebook_10204860956785508]

Have you tried using a USB cable with a Ferrite Core Noise Suppressor on it. Its what there designed for. Its a cheap fix that might work

they look like this

http://www.aliexpress.com/store/product/5pcs-pack-Movable-Offset-5mm-Cli...

Ok I will buy a handful of those. Hopefully they work! Thanks!

 

[hybridauth_Facebook_10204860956785508]

Have you tried using a USB cable with a Ferrite Core Noise Suppressor on it. Its what there designed for. Its a cheap fix that might work

they look like this

http://www.aliexpress.com/store/product/5pcs-pack-Movable-Offset-5mm-Cli...

Ok I will buy a handful of those. Hopefully they work! Thanks!

 

[audipheonix]

Have you tried to disconnect the power chord of mac and run it from battery , to see whether the problem persist ?