New Jays Audio flagship cd transport

I've often used upsampling with the CDT2 feeding an NOS DAC downstream.

Seems what we probably should avoid is though, upsampling in the CDT followed by upsampling again in the DAC.

The AES output on the CDT3 is excellent but RJ45I2S is superior. 
I would say these are the (2) best outputs

I’d like to thank "Todd tekaudiospecialties " Vincent " and crew for the great service and support .

Jay’s Audio CDT is a excellent transport !

Good to know you got the RJ45I2S to work with your DAC - motivates me to do the same.  I have a NOS dac (Metrum Pavane), so upsampling on the transport is fine in my set-up.  Upsampling does sound a bit different - too early to say much, but my initial impression was a bit more air and extension on top, maybe slightly more incisive sound - I'll chime in once I know something for real ; )

Upsampling can be a deep topic for sure. One problem with NOS at 44K1/48K frequencies is, the waveform starts to look bad as we go up in frequency. Really bad in fact by 20KHz for example as there are only 2.x sample points available per cycle at 44K1 FS. Could we draw the desired exact waveform through only those 2.x points? Seems problematic..

Some will argue that it’s ok, the FS components are above the audio band and thus don’t matter audibly. In a perfect case with a perfect NOS stair case waveform that is ~ true. Ignoring what ultrasonics might also do to the downstream components. But in the real world the stair case waveform can be imperfect (often is), which could/does put unwanted frequency content tones down into the audio band. This all adds up to raising the noise floor dynamically.

Perhaps even worse, there are beats that come in- the waveform is also amplitude modulated (ackk). My theory is, this could be a part of why old (current?) CD audio tended to have the timing/rhythm messed up vs analog.. Next time upsampling, try and see if it affects the music rhythm or not.

For those interested take a look at http://www.mother-of-tone.com/cd.htm It’s a great resource about CD format.

Higher FS ~ fixes all this basically. Which makes sense as more points gets it closer to an analog waveform. However, upsampling itself is not trivial nor a benign process unfortunately. Seems it’s likely best to avoid double upsampling in a system.

If only we could go back in time and make CD audio at least 96K FS.. The world has suffered from 44K1 FS.. /Lament

Early on I had the then new CD walkman, the first, the D50. Made a suspended carrier thing to use it in my car audio system (it would skip if you breathed on it, so much for the "walk" part lol). It’s probably still laying in a box around here somewhere. https://onlythe80s.com/238/sony-discman/ My gosh the truth is early CD sounded abysmal lol.. "Perfect sound forever", they crowed.. indeed.

Anyway, at the end of the day may the best sounding config win in a given system :)

I also concur that RJ45 I2S generally seems to sound a little better still IME vs HDMI I2S, for whatever reasons. TK