Watch out for cheap analog pro video mixers!

You have maybe seen cheap pro analog video mixers for sale on ebay or elsewhere for knock-down prices.
Just be careful that you know what your are bidding for/buying…

There is no question that pro analog video mixers of the kind that used to grace broadcast studios etc. seem a very attractive option secondhand. They usually have far more inputs than the prosumer models and have nice chunky BNC connectors etc fancy features, high quality, and SUCH a bargain price…BUT…. there is a big gotcha that will bite you on the bum if you think you can buy one of these and just wire up
some prosumer DV cams and be mixing away.

Almost all of these mixers do NOT have any kind of frame synchronisation or timebase correction
To put it another way, they assume that all video sources are already genlocked or synchronised and that they can happy mix between them without worrying about whether all the start of frames happen at the same time.

So…they will NOT work with your average DV camcorder or indeed any other video source that does NOT have a genlock input to allow frame synchronisation.

Of course if you have studio cameras or VCRs with a genlock input you CAN wire it all up to use one of these mixers, but I would suggest that unless you are setting up a permanent installation that this is all a major pain in the neck and should be avoided for VLOBLIVE gigs.

Just stick to a prosumermixer like an MX50 or an MX20 or the new generation Edirol ones that have frame
synchronisation built in and you will be fine.


2 Responses to Watch out for cheap analog pro video mixers!

  1. Pol Gleis says:


    How can i see if my mixer (just bought it on ebay) has syncronistaion? (the mixer is a cheap linear editing mixer not from panasonic)
    Once i worked with a mx30 and switched the cameras on one bus and the monitor (sony) did not show problems

  2. drc says:

    Hi Pol,
    If you let us know more details, e.g. model no, that might help.
    In general if the mixer specs don’t mention synchronisation, or timebase correction then you can assume it doesn’t.

    The MX30, along with most consumer mixers DOES support synchronisation, but in fact you will see a very slight freezing of the output, when you switch inputs on the same bus. The way to avoid this is to set the autofade time to 3 frames or similar and use autofade to do near-instant switching using the two busses.

    Hope that helps


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