thanks so much all you guys for these responses
unfortunately i only just discovered this thread wasn't in fact dead. just read them all. the forum didn't notify me (had to manually click the notify button....)
ok so my primary concern is not to intentionally be hot plugging etc. but instead if the firewire cable ever gets accidentally ripped out while the thing is on. or if i ever forget, or the computer decides to turn itself on at a critical moment (after turning it off, and the thing then clicks back on, and yes this has happened before).
So all in all trying to err on the safer side.
What strikes me here, is that the device in question (in my first post here, the saffire pro 40)... well it isn't actually powered by the firewire bus. So if i can disconnect or remove the power at the other end. Or use a different cable. Or modify the cable or it's termination. To get rid of the +Vcc and Gnd only, wouldn't that help to protect the device?
Because looking at where the signal comes in on the PCB to the TI firewire chip. It just seems to need those differential pairs to carry the signal, if that is enough without a ground reference?
Or maybe I should just keep the ground connected (so 5 pins instead of all 6?) ?
Also do you guys see a point that i could still order those TVS protection diodes? Because I have to order some other things (and for other projects) from digikey. And they seem to be pretty inexpensive and cool looking devices.
But my main question here is about modifying the firewire cable / link. Actually have already some spare 6 pin firewire 400 cable for trying that out on here.
See these 2x saffire pro 40s is my only firewire devices, it's not like I have any other types firewire devices to also plugin or use those same cables. It's not going to cause any difficulty for something else.
Anyhow at least will get the reply notifications next time. Thanks so much for these previous responses BTW. Really appreciate it.