How can the "Analogue section" of a DAC decide or affect the total quality of that DAC?

[Purité Audio]

Finest/most expensive does not mean best performance.
In some cases (one needs to know about the design and will need schematics or a LOT of experience) simply selecting better suited parts, which may even be cheaper than what's in there, or changing some values one could potentially increase measured performance.
An increased measured performance may not be audible.

In case of 'modders' the mods could even lower measured performance or knowing what's in there could alter the perception of the individual resulting in 'improved audio'.

Changing analog volpots could lower noise (when adjusting the volume) or have better L-R balance, particularly at lower levels. Better SQ/technical performance... no not really but again, knowing what has been replaced will alter the perception of the owner.

Of course the whole 'capacitor' story could potentially lead to better measured performance when very crappy or not suited parts were used to begin with.
In most cases changing parts for more expensive (audiophool) parts will lead to a guaranteed improved sound quality of the listener regardless if technical improvements have been made. That's how it seems to work for audio.

Solderdude does that mean by following the chip manufacture’s recommendations to the letter that’s as good as it gets ?
Presumably any changes away from specified will be measurable?
Best,
Keith

 

[solderdude]

Probably not.
The DAC chip manufacturer may be limited in the choice of opamps he has available.
A DAC device manufacturer may be less limited and could follow the basic schematic but use a different opamp.
That could make it worse or equally good.
With some tweaking of components one could possibly even increase measured performance using suited op-amps from other manufacturers than the one mentioned in the application note.

 

[Purité Audio]

Thank you, so one could make a design audibly/measured worse , you can perhaps improve the measured performance but audibly different/better?
Keith

 

[IAtaman]

does that mean by following the chip manufacture’s recommendations to the letter that’s as good as it gets ?
Presumably any changes away from specified will be measurable?

Usually in the datasheets you get a typical application circuit and that circuit would be designed by people who have designed the chip so if your operating parameters are similar, usually those circuits works really well. It is not uncommon though that people with a lot of of design and hands on experience can design a circuit that performs better than the application circuit from the datasheet. I think there are probably products out there which can perform even better than the specs of the chip they are built around which is amazing to see and is engineering artistry at its best.

 

[MAX232]

OK, thanks notsodeadlizard, for you obvious but not for me. All measuring results are indicators of the analog output and therefor it applies if it's good, the analog output stage is good too. I still need to get my head around the idea that this has become an exact science part vs a whole world claiming there must be differences. I just recently understood the theory that modern DAC's have moved the noise so low with oversampling that all the improvement made since it's 120Db+ is only for the specs. So i can basically choose the best looking, best features for my stack and get on with it.

 

[IAtaman]

I think component selection plays a role beyond the initial specs of the product. Silicon would not really age that much in my experience, but things like electrolytic caps can deteriorate over time, connectors corrode, thermal pastes dry out etc. So if you got an old amp, probably some of the caps will no longer measure to spec, especially the smaller electrolytic ones. Replacing those caps would be a good idea to bring the amp back to its design parameters.

A manufacturer can decide to go with components that has better lifetime for example but sometimes these components come with a lot of complications like lack of availability and supply chain issues, so beyond cost reasons manufacturers of large scale products might be forced to use mediocre components that perform well now but might cause issues in the future.