Absolute top tier DAC for standard res Redbook CD

Klh007,
Thanks for your suggetion.i will try transformer based mod for sonica dac,
Replace iv and buffer ic circuit with high quality microphone transformers.
Tube mod in such a small package is very challenge. I built all my tube preamps and power amps, the key for a good pre amp is regulated /shunt power supply, which take a lot of space.

Btw, the hidden gem of redbook cd dac is old bbrown 1074 dac chip based assemblage dac. I have one heavily mod w blackgate/silver mica and opa637s. Chinese audiophile writer mr chen had high praise for it(w/o my mod version).

Dlcockrum,
Humm,cnn.  Who‘s owner of cnn? He dumped his chinese wife right? You think i agree anything nonsense little  Cumo makes on cnn?

Regarding mod, as mr chen claimed, only good judgement should be based on golden ears,if and only if, no other way. Money is not, approach is not (tube vs solid state), feature is not even a fact for audiophilers. I perfect ok that none of my amps and lp turntables have remote control. So, why some device makes bettet sound? In dac case, in dgital domain, once power is clean, clock is acurate, data stream just feed the same dac chip w/o any difference (nowadays, chip makers reduced to very few anyway).
So the answer is how analog signal get filtered and amplified from dac chip analog output pins.cheap approach is ic based low quality circuit used in tv and computers, those design should not used in high end audio. But selling audio equipment is a buisiness, cnn like media feed all kinds of crab to confuse consumers. Use your ears, not looking at price tag to decide which one is better.

As oppo dac goes, it is my attempt to play both cd and dsd lp achieving files with a mobil phone app. I actually would be happy if it is half good as my assemblage. Now it exceeds my expectation:it has latest dac chip, it uses one of my fav voltage amp ic 4562, its usb interface is decent.i just fixed the weak spots of power supply and coupling crab(good preamp should never use capacitor coupling unless western electric ultrapath design for tube amp).
Btw, my korg dsd recording has same issues and more(bad ic chips in signal path), so i have some experience to deal with unnecessary coupling. In korg case, i just short the caps. My phono stage line out is transformer coupled, no reason why recorder needs coupling caps in front.

Guys, there is no doubt that some mods can elevate the performance a great deal. That said, it's not going to beat out any of the DAC's that are being discussed in the thread as he's looking for the best and not just good ones.  There are many really good DAC's 5k and below right now and they are there for every taste.  Again, a new thread for that would probably take off. Plenty of DIY's on the boards and it would be very interesting to talk about the mod and how it sounds vs XYand Z.  This just really isn't the thread for it is it?  

Dave and byang, please don't take this wrong, but I honestly come read the threads to get away from the political stuff.  I'm a retired Navy Commander and stay well versed on things, but this place shouldn't need to have to deal with that. I'm sure you guys understand and I hope you aren't made at me for bringing  it up.  I was emailed and messaged by two lurkers on this thread and it's only been within an hour or so of the back and forth.  Thanks