I still think the source first philosophy makes a lot of sense. See the Naim handbook given out to dealers
The source-first philosophy dates back to the 1960s when analogue was the undisputed king of audiophile source categories.
As mentioned earlier, analogue source components demand high-quality engineering and build as the tolerances required are very tight. Quality and cost were proportionate and entry-level turntables, for example, demanded some sacrifices while high-end turntables carried a price-premium due to the very fine tolerances involved in manufacture.
In these circumstances, the source-first strategy - both in terms of sequence and in budget allocation - made sense.
Also, back in those days, your mainstream audio buyer was not as knowledgeable about other factors that could and did influence sound quality. These factors included understanding of room acoustic aspects such as standing-wave nodes, side-wall reflection-induced phase smearing, etc. Other factors such as speaker cabling, interconnect cabling, and power cord effects were also not fully understood/accepted.
Given the changes to the landscape of audio in terms of digital sources, DSP-based room correction, affordable-but-effective cable options, etc. the relevance of the 'source-first' philosophy needs to be questioned and modified to fit these current factors.
Unless, of course, one is a self-confessed Luddite and is quite happy to ignore any changes that do not support the antedeluvian theories held...
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