The TT-High-res has a special driver mode.
It uses ECL. In escense this is the signal and the inverse of it send together. Kind of a Push-Pull. There has not been a converter for this. (to my knowledge)
Some speed may also be gained by increasing the ST-Ram memory size. If the Plug-in board has SMD-Ram Chips on it, these can be replaced by bigger ones. This gives a total of 10MB ST-Ram. (The maximum, I've tested it once, by replacing the 2MB on the board with 8MB and then adding a 8MB expansion board. It only gave 10MB)
The schematic diagrams of the TT are also available. This will also give some more info.
