Better cd SQ

I'm in the exact same boat as you, OP. I also have the CD6006. It sounds pretty good to me until I spin some vinyl on my budget setup. Relative to my vinyl, the CD6006 sounds a little grainy and veiled. I tried the Gustard R26 for a month and didn't feel it improved SQ to any great degree. The Pontus is an attractive option I'm looking at but at the same time, maybe the lesson is, I'm not a digital guy. 

I too have a 6006 used as transport initially to my PS Audio gain cell dac. Decided to upgrade from GCD got a ARC LS 25 and Pontus and was a nice improvement. I also stream and LP wit P6.

Denon DCD A110…Quad differential Burr Brown 1395’s…a handful of these are hitting our shores by end of month.  As close to vinyl as you are going to get with better dynamic range and lower noise floor.  Price will be extremely sweet…I am not a dealer nor am I affiliated with anyone, just a passionate audiophile who has been through the mill and happened across this special player.

Check out Ferrum Wandla DAC if you can. No personal experience, but got fantastic reviews, Stereophile rates it A+ and says it competes with DAC’s costing $10K or more. They also worked with HQPlayer to incorporate a few of HQ’s more popular filters into the DAC (user selectable of course). A bit over your budget, but not by much. I think it’s $2800 (without the upgraded HYPSOS power supply).

I've got a Marantz SA 8005 CD/SACD player. It's very nice and has the guts (DAC chip, etc.) to sound fine. But...I picked up a PS Audio UltraLink DAC at an estate sale for $25 (yes, that's right), and, well.... Admittedly, the UltraLink is very slightly louder than the Marantz; also, the UltraLink won't play DSD, so I listen to SACDs through the Marantz' internal DAC. But I can switch between the Marantz and the UltraLink with the remote to A/B compare them on Red Book CDs, and I always prefer the sound of the UltraLink. It's hard to describe the difference; the UltraLink just sounds more like live instruments, less like "reproduced" music. But, again, there's nothing wrong with the SQ coming from the Marantz. So, yeah; a stand-alone DAC can up your game in subtle but compelling ways.