Problem with older REL subs & class D amps

I'm posting this as a "heads-up" - per tech support at REL - that certain REL sub-woofers of the past do not accommodate tapping into the high level output of class D amps using the cables originally provided.

Options are (a) to use the low level (preamp) output into REL sub low level input, or, (b)obtain a special cable that they call "high level digital out" from a REL dealership.

Subwoofers designed prior to the rise in popularity of class D amps are apparently the ones that fall victim to this. Best to obtain details from a REL dealer or tech support at Sumiko. (It sounds like the folks at Sumiko hope that your dealer can help you with this... understandable, as this is the purpose of a dealer...).

Sigh.
Art