Dual Monitor-Video Splitter Setup Needed

chris sperachris spera
Posted:
in Genius Bar edited January 2014

I've got an Early 2011 15"MBP (no video problems yet) that I have connected to a Thunderbolt Display. I used to have it connected to a 22" widescreen VGA monitor.  I'd like to use both external displays. (I know the VGA is only SD while the TBD is HD) 

 

Does anyone know of a TB adapter, dongle or dock that has the ability to connect both a TB display AND a VGA monitor to it?  I'd like to do this on the cheap and know that I can do it with a USB dongle, but I'd rather NOT go that route. I'd like to split the video signal if possible.

 

Is there a MDP to VGA adapter with a TB pass-thru or some other dongle that might do the trick?  I tried asking this question at support.apple.com, but no one has answered the question yet.

 

Just as a quick aside, has anyone tried plugging a mini-display port to VGA adapter into the TB port on the TB display?  Could THAT get this done?

 

Thanks to any and all for reading and replying!

 

Chris Spera

Managing Editor Emeritus, BYTE.com

Comments

  • Reply 1 of 4
    MarvinMarvin Posts: 15,324moderator
    chris spera wrote: »
    I know the VGA is only SD while the TBD is HD

    You can still run a display in HD over VGA. If your display is 1680x1050 or 1080p, that's not SD. Anything 720p or higher is HD.
    chris spera wrote: »
    Does anyone know of a TB adapter, dongle or dock that has the ability to connect both a TB display AND a VGA monitor to it?  I'd like to do this on the cheap and know that I can do it with a USB dongle, but I'd rather NOT go that route. I'd like to split the video signal if possible.

    Is there a MDP to VGA adapter with a TB pass-thru or some other dongle that might do the trick?  I tried asking this question at support.apple.com, but no one has answered the question yet.

    Just as a quick aside, has anyone tried plugging a mini-display port to VGA adapter into the TB port on the TB display?  Could THAT get this done?

    It doesn't work plugging directly into the Thunderbolt display but this guy managed to get it to work with a Thunderbolt peripheral in the middle:


    [VIDEO]


    The peripherals are fairly expensive though. The cheapest is probably this one:

    http://www.amazon.com/Seagate-GoFlex-Thunderbolt-Adapter-STAE122/dp/B007IJ7UKE

    You'd then need a mini-dp to vga adaptor. Even then, your particular setup might not work properly. You can always return or resell the adaptors though.
  • Reply 2 of 4
    chris sperachris spera Posts: 4member

    I have no idea why this is so difficult.  

     

    You would think that something like this would be easy to do.  what happens if you want to connect more than 1 TB Display?  You should  be able to daisy chain right out of the monitor.  Why can't you do that with the VGA adapter?

     

    What happens if you want to connect more than 1 VGA display, HD or not? This seems like it would be a no brainer with my solution. If that's not going to work (I'm gonna try anyway...), then why aren't there adapters out there with a TB pass through?

     

    I don't have a problem spending a little bit to get this to work, but $170 seems a bit much without a real use for the adapter other than to act as a pass through.

  • Reply 3 of 4
    MarvinMarvin Posts: 15,324moderator
    chris spera wrote: »
    You would think that something like this would be easy to do.  what happens if you want to connect more than 1 TB Display?  You should  be able to daisy chain right out of the monitor.

    Thunderbolt displays work ok:



    but not standard displays:

    http://www.macrumors.com/2011/09/16/apple-thunderbolt-display-with-multiple-monitors/

    The article says:

    "It is unclear why simply inserting another Thunderbolt device into the middle of the chain allows the Mini DisplayPort display to function, but at least one MacRumors forum member has confirmed that he is unable to daisy chain his Mini DisplayPort-enabled Apple Cinema Display directly off of the new Thunderbolt display."

    Apple's support doc says so too:

    http://support.apple.com/kb/HT5219?viewlocale=en_US#minimul

    "Mini DisplayPort displays will not function if connected to the Thunderbolt port of an Apple Thunderbolt Display. Displays connected via Mini DisplayPort video adapter or cable to the Thunderbolt port of an Apple Thunderbolt Display will not work."

    Maybe it's something they'll fix in the next revision but they probably won't sell non-Thunderbolt displays going forward now that every Mac has Thunderbolt.

    Given that they advertise it as a Thunderbolt port, it is expected to be compatible with Thunderbolt peripherals i.e the adaptors so I expect they are compatible to an extent and the limitation would be on the part where the Mac recognises another display being attached. Maybe the TB display just needs a firmware update from Apple or some other software fix to get the display to appear.
    chris spera wrote: »
    I don't have a problem spending a little bit to get this to work, but $170 seems a bit much without a real use for the adapter other than to act as a pass through.

    It is a lot of money for that. If they drop the prices on the rMBPs, that might be a possible upgrade option as they have dual TB ports. That would avoid any possible GPU failures in the near future too.
  • Reply 4 of 4
    chris sperachris spera Posts: 4member

    Marvin,

     

    Thank you for your kind replies, information and help. I really do appreciate it. I need to figure this out as it seems silly not to be able to do this when you have the extra display hanging around.  I may head off to the Apple Store and ask them to help me find the right accessories to make this work.

     

    Kind Regards,

     

    Christopher Spera

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