I do it this way:
cable from computer -> in-line terminator -> adapter board -> hard drive
Your Mac or Amiga will _likely_ not work without one. I don't want to say "never" because SCSI termination isn't an exact thing - just google "scsi voodoo"
I've used the above combination in a Quadra 605, a Sparcstation LX, and various temporary installs in other SCSI based systems, as well as in external cases.
If the machine you are putting this in has other SCSI devices, especially an external chain that is terminated - as it should be - sometimes the internal terminator is not necessary - though it should be. Best way to sum it up is once you find a way that works, then it works, even if it's not what the spec says it should be.