Meant to say " I've been using the ASW 675 for years" with a Creek 5350SE, which has both preamp out and power amp in. Sorry for the omission/typo.
If the Creek has "Pre out" RCA jacks, you can use your subwoofer. I've used a B&W ASW-650 for almost 20 years with my 2-channel system. Pre-out means the signal strength varies with the volume control. If it's not variable volume, it is considered "line out" which is fixed volume. Line out can be used if the subwoofer has remote volume control. Otherwise, line out will be too loud to listen to.
I agree with Dweller. After looking at the manuals and descriptions of both components I suspect the reason the sub is described as "not suitable for use with 2-channel integrated pre/power amplifiers" is that with integrateds such as the 100A that don’t provide a means of connecting the sub between the amp’s pre and power sections you won’t be able to use the sub’s high pass filter function, that is intended to remove the deep bass content of the signals provided to the main speakers and the power amp section of the integrated.
That may or may not be a disadvantage depending on many factors, including the sonic quality of the sub’s high pass filter circuitry, the ability of the main speakers to handle deep bass frequencies without adverse effects on higher frequencies, the power capability of the amp, etc. But in any event many people successfully use subs without high pass filtering their main speakers.
So just connect the pre-outs to the sub’s line in connectors, and of course be sure to have the sub’s low pass filter switch set to "in."
Al & dweller: thanks for your responses. I'm happy to know that using the ASW 675 isn't completely out of the question but will be a matter of how well it will work with my system without the high pass filter function. I'm expecting the new Creek tomorrow and I'll report back on how things go.
Al & dweller: some two weeks later, using your advice for set-up and a lot of tweaking, I think the ASW 675 sounds better than it ever did in the previous system. FYI, I'm using it with a pair of B&W CDM 1 SE's, with the low pass frequency set at about 60Hz and at about 1/3 volume. The CDM 1 SE's low frequency response is 58Hz. I may continue to tweak as I listen through more music, but, so far, so good. Thanks for your help.