Using a lap top cd drive instead of highend cd player

I agree you're not getting the best jitter correction in your setup. There are several versions of the Audio Note DAC3.1, they are either NOS or 1xoversampling Dacs and do not upsample. To achieve the highest SQ, it's important to have jitter correction in front of the Dac.

A good transport will have a master clock to correct jitter. There are other benefits over a laptop CD drive such as vibration control and a higher quality lens. Some transports use a buffer after reading the disc to correct read errors.
And a good quality 75 ohm coax cable is needed for S/PDIF input to the DAC.

The outputs of a transport are typically S/PDIF coax, USB, and optical.
But since the Audio Note is unique and may not have a USB or optical input (it’s offered as an option) RCA or BNC coax is used.

A CDP will have the same digital outputs as a dedicated transport, some have AES (XLR). A transport’s only job is to read the disc and clock the signal in the digital domain. It then sends a datastream to the dac where it is reclocked again. CDP’s have an analogue output stage to go to a preamp. This is bypassed when using it as a transport to a dac.

The Pioneer would simply connect to the AN RCA input. I'm guessing that your dac has RCA and BNC inputs.
What coax cable are you using? The quality and length of the cable significantly influences sound quality.

Let us know how it works out. Is the Coax In on the DAC RCA or is it BNC?