The only newer DAC that I can think of that would be an improvement in that price range is a used EVS Millenium DAC. The DAC 2 would be the best, but those are usually over $500. You could find a used DAC 1A or 1B for that amount, but there aren't many and they don't come up for sale every day. Keep your eyes open.
If you're willing to try older DACs, you might be able to find an old Meridian, Muse, Wadia, Theta, etc. in that price range (pieces that originally cost thousands). They will have older DAC chips, but I think you'll find that their high quality designs, parts, and power supplies will still sound much better than most cheaper DACs with modern DAC chips. A new DAC chip isn't going to matter much if everything surrounding it is compromised. Most qualities of good DACs...transparency, lack of grain, soundstage, bass, etc. come from good design, parts, and a good power supply...not just the DAC chip.
Natalie does make a good point above...you could sell the Rega and try to buy a used Meridian 508/24. I know they've come down in price quite a bit, but I'm not sure if they've dropped that much yet. Just an idea...
If you're willing to try older DACs, you might be able to find an old Meridian, Muse, Wadia, Theta, etc. in that price range (pieces that originally cost thousands). They will have older DAC chips, but I think you'll find that their high quality designs, parts, and power supplies will still sound much better than most cheaper DACs with modern DAC chips. A new DAC chip isn't going to matter much if everything surrounding it is compromised. Most qualities of good DACs...transparency, lack of grain, soundstage, bass, etc. come from good design, parts, and a good power supply...not just the DAC chip.
Natalie does make a good point above...you could sell the Rega and try to buy a used Meridian 508/24. I know they've come down in price quite a bit, but I'm not sure if they've dropped that much yet. Just an idea...