MixPre-D to DSLR, will this work?

B

Bruce Watson

Veteran
Found this impedance matching transformer. Will this work for making the transition from an XLR cable from the output (balanced mic level) of a MixPre-D to a DSLR (unbalanced mic level)?

Yes, I know I can run an unbalanced line all the way from the MixPre-D to the DSLR via the MixPre-D's stereo unbalanced mic output jack. But when I try this with HMI ballasts within 10m or so, the unbalanced cable acts like an antenna and picks up odd 60-ish Hz noise from those ballasts. I don't hear it when monitoring at the MixPre-D's headphone jack, but if I move my headphones to the camera's headphone jack, it's there, and it gets recorded. Which indicts that unbalanced cable.

Yes, I could record audio to an audio recorder, but then I get sync issues on long form recordings like classes or seminars -- too much drift between the camera and the audio recorder. Client really wants to record audio in camera to avoid this.

So... will this thing work in the context I've described? If not, what will?
 
The MixPre-D's unbalanced mic output should work. But don't expect the greatest audio from a DSLR even it has a manual volume control option.
 
I use a passive Beachtek DXA-2T adapter to take LINE level signal from the MixPre and record it directly with my camera.

Yes, it's not a cheap way to go, but it lets you use both MIC and LINE level signals, gives you a ground-lift switch, along with two pots to adjust the signal strength.

Because it's passive, it doesn't effect the quality of the signal coming in, though it won't amplify the signal either. ( which is why LINE level is probably the best input for it )
 
The MixPre-D has an unbalanced stereo mic level output on a TA3 connector. A simple straight-thru TA3F to TRS miniplug cable would do the trick. SoundDevices part # XL-3F is one off-the-shelf example.
 
Steve House said:
The MixPre-D has an unbalanced stereo mic level output on a TA3 connector. A simple straight-thru TA3F to TRS miniplug cable would do the trick. SoundDevices part # XL-3F is one off-the-shelf example.
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As I said above, more than once, this doesn't work for me, and I said why in the OP. What I'm looking for is an alternative, and I'm asking specifically if the alternative I'm suggesting would work. No one seems to want to address that though. I don't know why, but it must be me. I'm not a great communicator, clearly.
 
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WHERE are you putting the MixPre-D? If the mixer is adjacent to the camera, it seems unlikely that you would get the interference you are describing, even in a high-noise situation as you describe. If you have a long distance between the mixer and the camera, can't you co-locate them?

Assuming that the noise isn't coming from the microphone or the mic-to-mixer connection??? Is the audio clean when listening on headphones on the mixer?

Are you powering the mixer and camera with batteries, or plugged into the power mains?
 
Richard Crowley said:
WHERE are you putting the MixPre-D? If the mixer is adjacent to the camera, it seems unlikely that you would get the interference you are describing, even in a high-noise situation as you describe. If you have a long distance between the mixer and the camera, can't you co-locate them?
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The unbalanced line is 2m. Not a long run, just too long.

Richard Crowley said:
Assuming that the noise isn't coming from the microphone or the mic-to-mixer connection??? Is the audio clean when listening on headphones on the mixer?
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Yes, clean at the mixer. Dirty at the camera. The only thing downstream of the mixer and upstream of the camera is this cable.

Richard Crowley said:
Are you powering the mixer and camera with batteries, or plugged into the power mains?
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Batteries all around.
 
Bruce Watson said:
The unbalanced line is 2m. Not a long run, just too long.
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So what happens if you use a 2 inch (5 cm) long cable?

You can hardly buy anything better than that SD mixer. ANYTHING you put between the mixer and your camera will diminish the quality of the audio coming out of that mixer. I would try real hard to just use as short as possible cable between the mixer and the camera.

DSLRs are not noted for their sound quality including dealing with those toy 3.5mm unbalanced auto-level mic inputs.
 
Bruce Watson said:
As I said above, more than once, this doesn't work for me, and I said why in the OP. What I'm looking for is an alternative, and I'm asking specifically if the alternative I'm suggesting would work. No one seems to want to address that though. I don't know why, but it must be me. I'm not a great communicator, clearly.
Click to expand...
Have you considered the possibility that the HMI noise is being picked up by the camera itself and not the cable between the camera and mixer? You might want to record a little test video with nothing connected to the camera audio input and see if the noise is still there. Second thought ... perhaps the shield is faulty on your cable, Check it with a tester.
 
Have you tried plugging an independent recorder into the mixpre and seeing if you can't record clean off that? I have shot hours of music separately and never had drift. Perhaps you should try a better quality camera. Can you rent a substitute? You can also get around drift by stopping after each logical class break.

alternatively, why not mount the mixpre under the camera, and bring the mic in via xlr balanced?
 
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