Doug Jensen
Carbonite Member
I never know anything is 100% sure unless I have tried it myself. 
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We have a Sound devices 552 with AES out on both left and right outputs and we do record four separate channels of audio on our F5. But as Doug said channels 3 and 4 on the camera can not be controlled with the current firmware on the F5 and I assume the F55.
You can be 100% sure now, from the Lectrosonics website;
Description: Mounting adapter to mount SR receivers into slot on Sony cameras. Makes connections with internal Sony connector. Second channel is not be enabled by camera manufacturer. However, second channel is correctly presented on Lectrosonics adapter.
Any place to put the SR receiver other than velcro? As an fyi, Sony tried to steer people towards their wireless slot receivers and didn't allow Lectro's SR to pass two channels by choice, not because it wasn't possible.
Frankly, everything about the audio design on the F's seem like an afterthought, from the headphone jack in the ear to the cheesy audio interface box screwed on the side. Just not enough available real estate, I guess.
As well as, the lack of proper physical record volume controls and the lack of a proper spot to mount a mic. The F5/55 was simply not designed for camera operators who need to control their own audio. The evidence is overwhelming.
I don't think it was until much late that former 2/3" shooters started wanting in on S35 gear and work, and the camera afterwards needed to be all things to everybody.
Doug - re your BEC side mount - is this possible using the Anton Bauer backplate for the F55 or just with the Sony batteries?
. . . but you have to wonder whether the design guys who asked cameramen what they wanted neglected to bring up audio - such a simple thing (one would think).