Not really much room to get it wrong, as there's only one output on the Studio Channel (on either TRS or XLR) - so either a TRS/TRS or a XLR/TRS cable from the output to one of the line inputs on the 2626. If it still doesn't work, make sure that you're getting a signal into the Studio Channel in the first place (in other words, make sure that phantom is on if needed and so on)...