recommendation for rca interconnect for deeper bass for dac to preamp

I don't think that the OP wants to use cables as tone controls, he simply wants to hear everything there is to hear, including bass.
Now, in a reasonably good system and with reasonably good hearing, cables do not sound the same, though some do sound similarly.
I have Purist Neptune, Wywires Platinum and Tchernov Reference MKII RCAs. The Wywires and Tchernov are not far from each other but still there are clear differences. The Neptune is different. All three give excellent bass and PRAT without artificial exaggeration.
You won't find Neptune or Tchernov used, Wywires sometimes does show up for about $750 RCAs 1 meter pair. either on Audiogon or on usaudiomart.com. Kubala-Sosna is another brand to consider, but I have no personal experience with it, though I trust people I talked to who use them. It's sound signature is closer to Purist, as I understand, even if not necessarily to Neptune model.
You might also consider new Purist Aqueous Luminist, $1200 retail, but I have not heard it.
Overall, of what I know my realistic choice would be Wywires Platinum. It sounds great in my all analogue set-up and it sounded excellent when I tried it with the Burson DAC in my computer based system. 

thanks for the input...

as much as I appreciate bluejeans cables my own experience with their toslink digital cable was that it decent but not as good as the lifatec toslink (sure its $25 versus $100 but the lifatec just immediately sounded better to me.

I just dont believe wire is just wire.....anyone who has ever heard a nordost cable knows its very transparent and fast but not known for deep rich bass....the purist dominus has incredible rich bass and midrange but is rather warm......both cables both excellent at different things.....to say all wire sounds the same is to ignore what I hear and feel....

perhaps the blue jean measures as good and perhaps it does not....its a good value but if you only want value isnt this the wrong hobby.....most people would say bose is good enuf and beats headphones and even mp3 is good enuf....would you put cheap tires on a porsche?   in any event there is a lot of equipment and cables that are good value but even that is relative....

I tried tonite an older cerious extreme graphene interconnect (a good value budget cable) and the music sounded very good nothing got in the way of the music. Nothing missing or annoying to it.  However when I swapped in a loaner townshend fractal rca interconnect there was so much more information there.....is it as good as my galileo sx unfortunately no because the sx has the same amazing detail and more body to it...but it cost 5x as much.....so might just stick with the fractal for now

I would just keep switching cables from phono to dac if I were you, unless it would be too inconvenient.

I suggest you try Auditorium23 cables, easily the most transparent cables I have found

I suggest reaching out to either Audiogon members Wig, williewonka or grannyring and see if one of them will build you a double helix cable (see the thread ). I have them in both of my systems, along with a double helix digital cable in one of the systems.  Very musical