Here are two sound demos of a TR606 and a CR78 I midified.
Note the full velocity sensitivity capability of the 606 and the pseudo-velocity sensitivity of the CR78.
Some more infos about the CR78 mod:
Depending on the midi velocity sent to the device, the master volume is adjusted. That is of course not the same as full velocity sensitivity, but gives you a surprisingly great amount of flexibility. Think of the 808 for example which has one accent track – this is similar, but you can adjust the accent on the fly.