unattached newbie seeks compatible dac

I like vinyl and continue to buy records. But I play a lot of music (classical, jazz, country) on my Imac. I have a decent but not exalted system - BATVK20 preamp, Odyessey dual mono amp, Acoustic Zen Adagio speakers. I have a Perpetual Technologies P-3A dac. I download audiophile music (flac to lossless) from, among others, Linn. I'm not getting the sound I would like - good, nice, but not stirring. First candidate for replacement seems to be the dac. What to get? Budget is flexible - I can pay more if I want to, but don't want to overpay given what I already have. I don't need a preamp, so don't see why I should pay for one. I don't need volume control because the BAT will adjust the volume for each input. I hear all kinds of things about USB versus toslink, ideally would like to see for myself by having both inputs. I used to have tubes, liked the sound, so would be open to a tube dac. I've read very positive user reviews of the tadac, but no professional ones (are there any?). I see a lot of used higher end dacs here for 25 to 50% of the new price, but most are from 5 to 15 years old. Have there been advances such that the new ones are better for the same price as the used ones? I live in the wilderness. Electricity is available, but audiophile stores are not (there are compensations). So, I have to buy it to hear it. Suggestions?