It sounds like the H7600 can take much more than your X-desk can give out. Its input clips at about +25dBm. But, your setup is probably OK as is – if the highest level you see on the 7600 is -12, this means that you have 12dB of extra headroom in the 7600 – this is not a bad thing  as some effects can increase the level of parts of the signal.

You could use the LEVELS/inputs/gaintrim control to get a higher level on the 7600 if you feel you need to. See UM p.29 for details.