Transport - will it really make an improvement

Looking for honest advice. I am considering buying a better transport, and cant yet convince myself that it will really make an improvement in my system. At present, I am using a Pioneer elite DV-05 dvd player as a transport with an outboard, Assemblage, platnum dac and upsampler. I am overwhelmed with the improvements the dac made in my system, in lieu of using the inboard dac in the Pioneer Elite. However, I'm just not convinced, due to lack of digital knowledge, that a digital output from one source could be that much better than another. I seam to think that differences in quality of cd players, are mainly attributable to their internal dac's and not the transport or digital side. Of course, I maybe completely wrong!! On the other hand, I would hope to expect a difference if comparing my 500.00 dvd player, to say a 6k transport, but are not looking to spend any where near that much money. Please enlighten me with some education, and if you have any recommendations on a used transport for around 1k. Thanks, Steve

Oh, in case it matters, I have a pair of Innersound Eros MK1 electrostats with their new xover bass amp and ESL amp + good cables.