Path of signal from turn table to speaker

Lewm it would seem then that the phonostage is likely more of what contributes to the sonic output and all its qualities rather than the amp (assuming the pathway is a separate phonostage connected to the amp analog in)? This would also suggest the amps output from a digital rather than analog source should vary greatly as the digital processors including DAC are bypassed through the analog pathways? The sound character could be very different depending on the source. I mention this since many people like to talk about the sonal character of a particular amp. 

The CXA81 contains a built in DAC, it will take a digital input and convert it to analogue, the amplification is in the analogue domain. There are also other purely analogue inputs that will accept a line level analogue signal such as that put out by your Rega phono stage. The output stage is class AB.

In a nutshell: no and no.
Its pretty straightforward ( i wrote "simple" and caught myself). With a few exceptions, and those are recent, the signal path is entirely analog. DACs and ADCs are only used for digital sources - and in 99%+ of cases those digital sources are converted to analog for most processing and amplification. That's the function of a DAC and every CD players contains a DAC.

If you begin with vinyl it goes into a filter that mirrors the LP recording filter (an RIAA playback filter) which is packaged with a TON of gain to bring the signal from 1-5mV to roughly 1V. Then to a preamp with very modest gain but lots of switching and controls. Then to a power amp that takes it from ~ 1V up to whatever rated output is - typically 20-40V. The power amp also adds a high current buffer stage capable of driving 2 ohm to 16 ohm loads and therefore delivering several amperes.

End. Unless you are streaming or playing a CD.

Yes, digital amps and processing are gaining ground, but that is very recent and still very rare. Class D (digital) amps are another complication not worth getting into now.

If you are among the 0.1% with a high end digital preamp and amp, then yes you would use an ADC and would essentially defeat the desired characteristics of vinyl.

Moving magnet cartridges need a phono amp with a gain factor of about 100X moving coils need about 1000X. I am keeping this very simple. Both need a filter that rolls off the high frequencies according to a long-established standard. At 1 kHz this requires yet another ~7X gain, assuming it is performed passively.
G

thinking about what you have heard, i’ll add this: in most studios things are immediately digitized and processed in the digital domain, using both digital mixing boards and more often ProTools software.

In the studio case, music -- often individual instrument tracks -- are typically sampled at 24/96, providing lots of headroom to process things without compromising fidelity (in theory). It also allows recording engineers to be sloppy since 16/44 only delivers 96 dB if level sets are done accurately, an art that seems to have been lost around 1968.
I, in fact, believe that it is in the studio where the benefits of HD are clear -- or clearest.  Really well-done 16/44 can be pretty terrific - but that is often shown by 1960s-era verve, mercury or other recordings done simply on tube-powered analog tape machines by loving engineers (like Bob Fine).

Class D is a switching amp, NOT digital. Don't be misled by zealots.
It was invented in 1950.
I've got an A/B and a D and the D sounds better. It's all in the implementation.
There are Class A's that sound shitty with most speakers.
BFD