Noise when recording

S

shinyst

New member
On location the other day I ran into a troubling scenario with noise, I think it has to do with faulty AC wiring but I'm not sure. Here's my setup :

- Audio Signal Path :
Audio Technica 897 (no battery) connected via a 25 ft XLR cable to a Zoom H6n (48V phantom power).
The Zoom h6n is powered via a 5V USB powersupply.

I have lineout going from the zoom into a Canon 7D, which in turn is powered by a AC adapter (ebay knockoff).

All powersupplies plug into a single elcheapo strip which also has a LED spot light plugged into it.

When I have all of this connected to the wall socket at my place, known well grounded connection, the recorded sound is very clear without any distortion whatsoever.

However, the other day at a location I hooked up the strip to a wall socket and for some reason the sound coming through the AT897 channel was HORRIBLE.. there was a persistent buzz, and pops and clicks all over.

Oddly the sound recorded through the Zoom's own XY mic was perfectly clear!!

I didn't have the chance to plug it into another wall socket to see if that made a difference.

What could be causing this? At first I figured ground loop, but giving all of them were feeding off the same strip that seems unlikely. Could it be floating ground?
How do I solve this at other locations where the AC power isn't well wired? (running all my gear off battery unfortunately isn't an option)
 
This is just a stab but is the canon 7d input stereo?
If so, it's not likely to be balanced which would make your setup susceptible to noise from power transformers etc.
 
You could try running the Zoom with batteries (rather than the AC-USB adapter) and see if that makes a difference, because it sounds like the noise was happening due to the phantom power provided to your mic (as the built-ins didn't have the noise).
 
Sorry, forgot to mention I did try the zoom with only fresh batteries (no USB), that didn't help either.


mjbphotos said:
You could try running the Zoom with batteries (rather than the AC-USB adapter) and see if that makes a difference, because it sounds like the noise was happening due to the phantom power provided to your mic (as the built-ins didn't have the noise).
Click to expand...
 
I 'think' the 7d has a mono input.. in either case I was recording to the SD card on the zoom too and that also had the distortion.


Steenamaroo said:
This is just a stab but is the canon 7d input stereo?
If so, it's not likely to be balanced which would make your setup susceptible to noise from power transformers etc.
Click to expand...
 
mjbphotos said:
Do you have another mic cable you can check it with?
Click to expand...

unfortunately I don't have another cable, but the odd thing is that I used the EXACT same setup (lights + camera + recorder + mic + cables + power strip) after getting back home and I don't hear any distortion.
 
arcaxis said:
What was the environment like that you were recording in?
Click to expand...

It was a regular suburban home - not an industrial setting, certainly no heavy machinery operating in and around the house.

In the future, If I do use a tester and find say that the ground isn't really connected or some such, is there something I can do to make it work? are there any power strip attachments I could use to filter such stuff out?
 
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