IS THE WEISS 204 A SUBSTANIAL UPGRADE FRON THE CHORD QUTEST

Resolution is defined by the sample rate and bit depth. Both of those in turn are defined by your source. Any DAC that changes even a single bit in the bitstream is by definition, defective. So, no. The Weiss will not have, cannot have, better resolution. Nor is it likely to be meaningfully quieter, since the noise floor to peak output on both is far greater than dynamic range of your room noise floor to peak system SPL, which in most domestic systems is lucky if it hits 60dB.

That said, does it have noticeably better reconstruction filters or a better analog output? Those are things you may possibly determine through listening.

All DACS must be 100% accurate in decoding the bitstream or else they are defective. So yes, all DACS have to sound the same. Where they may vary is in reconstruction filters and analog output stage.

Power supply differences are again largely mythical unless you are seeing power supply spuriae in the audio bandwidth and at levels within the dynamic range of the system. If your system has a peak SPL of, say, 113 dB, that requires a 90dB sensitive speaker and 200W of amp. If the noise level in your home is 50dB, that gives you a system dynamic range of 113-50 = 63dB. If the noise from your DAC is -100dB, improving to -110 dB is "measurable, not meaningful" because that noise is already so far below the noise floor of your system. Just like if wearing a certain type of shoe sole reduces your chances of being struck by lightning by 50%, no rational person is going to throw out all their other shoes. The improvement is measurable, not meaningful. 

So, you may find very minor improvements from reconstruction filters or analog line driver circuitry, That's for your ears to decide.

Far more likely, any improvements in your (very nice, BTW) system can be achieved through improved room acoustics. Far and away the weakest point in most systems. 

@audphile1

I think I wasn’t clear in what I was saying. The job of a DAC is to convert the digital bitstream input into an analog output. All DACs must do that identically or the ones at variance are defective. But that part of the job is incomplete. The signal must then pass through reconstruction filters, then passed through an analog line stage before one can listen.

The reconsruction filter used in a digital to analog converter that eliminates the stair-stepped waveforms created in the digital sampling process and restores frequency, amplitude, and phase of the original signal. The process of digital sampling creates stair-stepped waveforms that resemble square waves (increasingly so at higher frequencies). These waveforms contain the original signal, but also have high frequency noise and harmonics added to it. The reconstruction filter – which is basically a low pass filter – removes all of the high frequency signal above the Nyquist frequency that was induced because of the sampling process, leaving a “smooth” sinusoidal type waveform resembling the signal that was originally sampled.

lAnd it is in those stages that the differences in sound quality originate, not in the DAC stage itself. It is our tendency to group those stages and refer to it as the DAC. The difference is not just semantic, rather it enables us to focus the discussion on those areas that actually can impact sound quality.

https://support.auralic.com/hc/en-us/articles/206806457-What-s-the-Difference-Between-PCM-and-DSD#:~:text=A%20reconstruction%20filter%20is%20typically%20used%20in,are%20normally%20used%20in%20PCM%20encoding%20systems.&text=The%20dynamic%20range%20of%20DSD%20decreases%20quickly,rising%20noise%20floor%20just%20above%2020%20kHz.