DVC 4 Gold interface Noise Issue

[WayScar]

Hi All

I'm experiencing a loud digital noise through the PA and In Ear Monitors in the band in which I use a DVC4 Gold interface running on Daslight 3. It seems to only have started once I upgraded from the DVC3 512.
My set up is as follows:-
I have a Yamaha Tyros 4 Synth which runs Midi Click tracks with Midi note info to trigger scenes on D3 via a USB/Midi Cable into my laptop. (works perfect)
My laptop is a 6 year old HP Pavillion DV9 Core i7 machine which works perfectly (on it's original Power pack but new unbranded battery).
I link the laptop to the mixer with a 3.5mm stereo jack to play audio files with some scenes.
As soon as the interface is plugged in and the led indicators start their "data blinking", the noise comes through all the audio channels which the Tyros Synth is plugged in to. If I remove the USB cable linking the Tyros synth to my laptop, the noise remains. If I remove the stereo jack from the laptop, the noise remains. Only when unplugging the DVC 4 Gold interface from the laptop does the noise cease. Not ideal!
I'm just after some suggestions to help stop this nuisance noise. I haven't yet had the opportunity to try a different laptop or try my old DVC 3 128 (which isn't suitable anyway).
Any help in this will be greatly appreciated.

Regards

Wayne

[Benno]

Hi Wayne, thanks for the message. Can you tell me do you still get the interference when you disconnect the XLR cable from the DVC4 Gold to your fixtures (leaving the controller connected to your laptop)? Also if you can try with a different USB lead to see if that helps?

[WayScar]

Hi Benno

Yes, the noise does continue without the XLR cable connected.
I have tried a different USB cable connected to the interface and it was the same. Strangely, moving the interface around in the air effects how loud the interference noise is, much like an aerial.

Hope this helps.

Kind regards

Wayne

[Benno]

Hi Wayne, thanks for the info. Can you tell me does the noise still happen without the laptop connected via power supply (battery only)? If you haven't already would you be able to test with a different laptop and let me know if you hav ethe same problem? Cheers

[WayScar]

Hi Benno

Sorry for my slow response, work is crazy!
The noise does continue when the laptop runs on battery. I haven't been able to try a different laptop.
I tried filtering 2 of my 4 Tyros 1/4" audio outputs through passive DI boxes recently. The nuisance noise was slightly reduced on those two channels. I have taken a risk and bought a 4 channel professional Active DI box/transformer/isolator which I will try this coming weekend. Can you enlighten me on your theory as to what may be causing the noise?

Kind regards

Wayne

[Benno]

Hey Wayne,

Thanks for trying those tests. To try and get to the root of where the problem is coming from it will be a case of reducing the system right down and adding connections one bit at a time.

Test 1)
• Plug in the PA
• Plug in the Synth (through new DI box)
Are you getting any noise at this point?

Test 2)
• Connect Laptop (important: run laptop from battery only and don’t connect any audio)
• Connect the Synth with USB
• Connect DVC4 Gold (Important: don’t open Daslight 4 software)
Are you getting any noise at this point?

Test 3)
• Same as above but once DVC4 Gold is connected then open Daslight 4 software
Any noise?

Really if you can it would be good to try with a different laptop to see if you still have the same problem.

Also if you could test with a different USB lead between the synth and PC. A USB lead with a ferrite choke (see pic) or clip on ferrite bead might help reduce interference. Also if you could try with a powered USB hub to see if that helps.

It could be noise generated by the computer on the USB line.

At first we thought it might be an infinite ground loop but not so sure about that now as you tried without power to the PC.