Overdose, thank-you for your forthright response. To tackle your points in turn:
Overdose said:
What evidence do you have for the sound being inferior and inferior to what?
If you had indeed read the previous post and the one that it linked to, you would have seen that I was referring to two elements:
1) There are better DACs available than the one contained within an Apple Airport Express, and;
2) There are alternative streaming solutions that offer advantages and disadvantages when compared with an AEx.
The sound from the analogue output of an AEx is inferior to that from a number of DACs, but the four others that I have at the moment and consider to sound 'better' (mainly in terms of presenting a more 'natural' and 'organic', i.e. realistic sound) are an Audiolab 8200CDQ, Audiolab M-DAC, Beresford Bushmaster, and HiFiBerry. I'm sure you'll be able to find many others that agree that whilst the AEx delivers perfectly adequate analogue output, it is not up there with the best DACS, albeit many of those cost a lot more money. As for other streaming solutions, even much cheaper options can produce benefits over-and-above the AEX, notably in terms of jitter, which can impact on sound quality. The RaspberryPi + HiFiBerry DAC is a case in point, but the main down-side for me of the AEx is that it does not offer audio out via USB, which I have found to be preferable to S/PDIF (Toslink). So, for example, the CuBox i2 Ultra that I referred to has both USB and S/PDIF output, so is more flexible.
Overdose said:
...you don't seem to understand the technology, but persist with a lot of the myths surrounding digital.
Strong words - perhaps you could expand? I understand the technology sufficiently well to have implemented a multi-room AEx set-up and a number of alternatives, including a RaspberryPi running the Linux Volumio code, via USB to some of my current DACs, and also direct to analogue with the on-board HiFiBerry DAC. Having done so, I took the time to write up my findings on these Forums in the hope that they would be useful for others.
Overdose said:
An Airport Express, along with a great many other DACs is quite able to produce superior results...
What evidence do you have for the sound being superior and superior to what? Sorry, but I'm afraid you have fallen into your own trap there.
Overdose said:
...it's limitation of 16 bit/44.1KHz is not actually one a sound quality, but rather file type
I don't wish to get into a debate over whether hi-res files sound better or not, nor to split hairs over the difference between bit depth, sampling rates and file types, which I believe you have incorrectly conflated here. I was simply advising the (other) OP that AEx cannot play files at higher resolutions than 16/44, whereas other DACs and streamers can. As I said in my other post (that one that you claim to have read), "None of these may be particularly important to you, in which case please ignore this post and go with th AEx - it is a functional and relatively capable device that I have enjoyed for many years now." That was referring to the three points that I had made above in that post, i.e. USB output, hi-res playback, and direct streaming from a NAS.
Overdose said:
... a cheap device like the AEX can do all that is required for optimum CD quality playback.
'Optimum' is a very contentious and unsubstantiated statement in this context, especially as I have pointed out previously that some AEx units have very high levels of jitter, so much so that I cannot use the Gen 2 AEx with my Audiolab 8200CDQ - it continually loses 'lock', causing drop-outs and pops from the speakers. I don't consider that to be 'optimum'. I have already covered the point about hi-res above, but you are correct - AEx is limited to 16/44, i.e. the same as a CD.
Overdose said:
A much greater focus and budget allocation needs to be given to the speakers.
The OP of this thread asked the question "What would be a suitable dac be for my system? I don't want it to be excessive but again I don't want it to be a limiting factor." He also went on to add, "It's unlikely I will be updating my system for a while." So, whilst you may be correct in your assertion about the budget for speakers, he has some decent speakers already. I really don't see how that point is helping to answer his question.
Anyway, I'm glad to see that the OP has now bought a seperate DAC and can connect via a number of methods, one of which may prove to be an AEx. From my own direct comparison of a number of seperate DACs with the analogue output from an AEx, I am sure that he will find it to be superior.