The Wharfey can handle it, but can your amp ? The 750 will put out a DTS signal, but like DD, won`t decode it. That`s down to the amp with the Wharfey. What amp do you have ? And how are you wired up - digital cable or phono leads ? Lemme know and I`ll try and figure it out.
Failing that it could be the discs - I take it we`re talking Region 1 here, cos Region 2 was DD only...