July 4, 2015 at 2:58AM, Edited July 4, 2:59AM


A7s and Tascam DR-60d audio hum

I have a Sony a7s and a Tascam DR-60d that are both being powered by vmount battery through an Ikan power distribution attachment. I originally planned on powering the Tascam through the USB port on my ikan distro. But when ever I connect the Tascam to the power and then to the a7s I get a terrible hum. I'm pretty sure it has to do with the ikan distro because I can power the camera through its original batteries and power the Tascam through the ikan distro with no hum. I don't even have to power on the Tascam to get them hum when it's all being powered through the same source. I also tried re-wiring the Tascam so I could plug it in straight to the 5v power connector (2.5mm?) but still had the hum. I can powers everything from the same source and not get the hum if I don't send the audio from the Tascam to the a7s, but then I have to line up the audio in post witch I'm trying to avoid. Does any one have a solution and/or know of power and audio wiring that could fix the hum? The hum over powers any signal that would come through


I have a Tascam DR-70 recorder that has a noise-floor problem when recording from the 3.5mm MIC level out, but this can be fixed with a 25 dB Sescom attenuation cable. Here's the cable that fixes the problem...

Sescom Line to Microphone Attenuation Cable for HDSLR Cameras

To use this cable you set your Tascam recorder to output a LINE level signal, and then use this Sescom cable to bring down the signal strength to something that your camera can record.

Using my Panasonic GH4 with my DR-70 recorder I am getting a noise-floor level of -70 dB RMS, which is the limit of the GH4 camera. ( it's about the same noise-floor as a Zoom H4n recorder )

July 4, 2015 at 7:24PM

Guy McLoughlin
Video Producer

Powering the 60D with USB is creating a ground loop. This has to do with how it is wired (in simple terms, that is). If you were just powering the device it might be okay, but running audio out of it is going to create lots of problems.

July 6, 2015 at 8:22PM

Joshua Bowen

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