DAC under $1K


Has to sound noticably better than the CD players I already have, ie. Philips CD-80 & CAL Tercet MKIII. Will use the CD-80 as transport. Tried AVA Omega & Fet Valve DAC's in the past & these are no better than what I have. Never heard, but am familiar with by reading reviews, etc. with Ack, Attraction, DAC AH, used Classe DAC-1, etc. I am DIY ready if the DAC AH is worth the bother of rebuilding? Using DIY 2A3 Loftin-White amp & Klipsch KLF-20 speakers.
5u4
"As far as sound, dynamic bass, transparent mids & smooth highs + analog sound, leaning towards the mellow side, definately nothing bright."

You may find the Mhdt Paradisea NON OS tubed output Dac to your liking. You can find them on Ebay from time to time for $499 plus shipping. They go fast..so you have to check regularly to snatch one up. The Dac is very transport dependent. So the better the upstream clocking.. the better the Dac.
I've never heard it myself, but all descriptions (by users) of the Electrocompaniet EMC-1UP upsampling DAC exactly match your descriptions. It's about $1200 used, just above your budget, but could easily be resold for about the same money.
While the aesthetics may not be your cup of tea, Kora's Hermes dac is available used at your price point from time to time. It's one I would consider without hesitation given your stated preferences. I would also consider a used Electrocompaniet dac, very much in line with your desired sound.