Can you feed timecode from a Tentacle device into the HDMI input of the Sound Devices MixPre 3 / MixPre 6?
Answer:
Unfortunately not.
Why?
Tentacle generates timecode according to SMPTE 12M. HDMI is an interface for transmitting uncompressed video and audio data. Here, timecode is embedded into the video stream. Both signals HDMI and SMPTE 12M timecode are very different from each other, so you can not just solder a passive cable adapter to make this work.
Even if Tentacle did generate an HDMI video signal with embedded timecode, the current consumption would be so high, that the Tentacle battery wouldn’t last your first scene. This is because generating HDMI video signals (>3.96 GBit/s) requires a lot of processing power.
Solution:
In order to use the SD Mix-Pre, simply use the provided black Tentacle to DSLR Mini Jack cable and connect your Tentacle to the Aux/ Mic In port on the right side panel of the Mix-Pre. See full article about the timecode workflow here.