TV Hum

[Cameron Pullmann]

Coming from a church setting, we had a SoundCraft Expression Si 3 installed in the sanctuary recently and everything has been good until we installed a new camera. We plugged the sound output from the board into the 3.5mm port on the camera so we could output everything in HDMI and there is a constant buzzing or hum on the TV's playing that signal. The TV sound feed comes from one of the mix outs directly from the board and goes straight to the camera. The old camera used a RCA video out and the sound was added in a converter box via RCA/, so no help there.

I tried it on our old board, which is a Yamaha MX200, directly from the 'tape out' which is RCA and it doesnt do it. The camera has gain options and I have played with those and that doesnt change anything. Tried different cables, they all doing coming from the SoundCraft. I am by no means a pro so I believe it is something simple that I just dont know about or missed. Any help is greatly appreciated. Thanks

 

[Tim McCulloch]

It's a ground loop from the mixer/camera and the TV. For whatever reason the Yamaha had better ground signal design.

 

[Mike Caldwell]

How are you adapting from the XLR output on the board to the 3.5mm input on the camera. If the 3.5mm is a standard stereo mic input you do not want to have it wired straight thru like pin 2 to tip, pin 3 to ring, pin 1 will go the sleeve.

 

[Cameron Pullmann]

How are you adapting from the XLR output on the board to the 3.5mm input on the camera. If the 3.5mm is a standard stereo mic input you do not want to have it wired straight thru like pin 2 to tip, pin 3 to ring, pin 1 will go the sleeve.

Thanks for the reply. I have tried several things. It originally output from XLR to RCA that was then combined with the video signal of the old camera in a conversion box that pushed the whole thing in COAX. So I took the RCA that was there and put an adapter on that that was 3.5 on the other end. That was the same method I tried on the old Yamaha board. That hums.

I have also tried a XLR straight to 3.5mm and that also hums.

Is there some sort of Dbox that would help?

 

[Cameron Pullmann]

It's a ground loop from the mixer/camera and the TV. For whatever reason the Yamaha had better ground signal design.

Thanks for the reply. Is there anything I can do or buy to mimic what the Yamaha does?

 

[Brian jojade]

http://www.mcmelectronics.com/product/555-18936

Something on these lines would do the job.  Pretty much anything with an isolation transformer should do the trick for you.  This one is on the expensive side. There are cheaper options out there.

 

[Klaus Zimmermann]

im using these several years now (sorry for the german shop link):

https://www.monacor.com/de-de/monac.../signalverarbeitung/signaloptimierung/fga-40/

or

https://www.monacor.com/de-de/monac...ignalverarbeitung/signaloptimierung/fga-40hq/

 

[Mike Caldwell]

Here is a Whirlwind interface that has a couple of interfacing options, I have one, I don't use it everyday but when I do it works perfect. I'm actually taking it out in a couple days to send an audio feed to a lap top that will be used to live stream an event I'm providing sound for.