A reasonable step up from Rega Saturn CD player?

Seems like your budget does not allow you to go much above the Saturn. As a rule of thumb you need to spend double to make a worthwhile difference.

Maybe rethink the computer route - a mac mini $600 plus a W4S DAC2 ($1100 used) will significantly outperform the Saturn and pretty much anything under $5k. I know, I had a $6000 Simaudio Moon player previously.

Given that you have a you have a DAC, have you considered a Meridian Transport? They sound great, and the market for them has gotten soft pretty much across the board.

For about the same price as a used Saturn, you can pickup a Meridian G98DH, which while dated as a DVD is still a crazy good CD transport.

Another option is the Oppo95. Again, for about the price of a used Saturn you get good sound and, as spindles go, is about as future proof as it gets.

Yet another option is to acknowledge that the Saturn is a great player, and to simply enjoy what you have.

At the same time, I was recently in your shoes. I upgraded the Saturn to a Naim CDX2, which was absolutely amazing. I ended up trading it back after a year b/c I didn't feel comfortable having that much cash tied to a then 7.5 year old spindle. I did find a pristine G98DH which I still own and happily consider a keeper.

Jas musik 1.2 tubed cd I have seen these used for $600.00 or a raysonic 168 which is the same as the ayon just less money. Best

Bryston, DENSEN or Sim Audio.....

I bought the REGA ISIS Valve and all made my short list that I auditioned (my buddy has the BRYSTON in his kit)