There are 8 line outputs on the Studio 192 that I use to create 4 stereo headphone CUE mixes. Works perfectly !! I'd like to create several more headphone CUE mixes using the DP88's DB25 pin connector to do this. As this device is advertised to allow for output expansion but not very clear as to how to actually connect up other output devices such as an HP60 headphone amp to the correct DB25's breakout harness. If you know how to do this, please respond. Much appreciated.