Echo Express III and Echo Express Pro (HD Cards)
 

http://www.sonnettech.com/product/echoexpressiii.html

http://www.sonnettech.com/product/ec...sschassis.html

Both of these products are coming out sometime this summer. It appears that both boxes, the Express III (3 Full Length PCIE cards) and the Express Pro (2 Full Length Express Cards) can handle either an HD2 or HD 3 or any other PCIE Full Length configuration of cards.

Any reason to believe that either won't work with my legacy HD PCIe Cards?

Re: Echo Express III and Echo Express Pro (HD Cards)
 

No, but I think you should ask this question from Sonnet directly.

Re: Echo Express III and Echo Express Pro (HD Cards)
 

If you're on a Mac, they probably won't. Thunderbolt devices for Mac require a specific Thunderbolt aware driver for the specific cards being used. HDX and HD Native drivers have been written into Protools since 10.3, but I don't know if they ever plan to have any for the older cards. And so far, I don't know if anyone's gotten any other brand of chassis to work with them.

This is on the Mac side. On Windows, there is no such requirement, so it could be a possibility.