with the level of quality of your dartz amp & pre-amp I doubt that a tube pre-amp at under $5000 or even $8000 would give you as much as satisfaction with your s/s dartz amp.
Even though one is s/s and the other is tube, the cheaper tube amp will not give you the same level of refinement as the dartz.
I have tried this route on numerous occasions & it always ends up disappointing. (always to the detriment of the cheaper component.)
Personally I would hold off to that purchase.
However if you would insist, i can highly recommend you give one of those tube lamm power amp a spin. Those have similar level of pedigree as your dartz amp.
Good luck.
Even though one is s/s and the other is tube, the cheaper tube amp will not give you the same level of refinement as the dartz.
I have tried this route on numerous occasions & it always ends up disappointing. (always to the detriment of the cheaper component.)
Personally I would hold off to that purchase.
However if you would insist, i can highly recommend you give one of those tube lamm power amp a spin. Those have similar level of pedigree as your dartz amp.
Good luck.