@lanx0003 You've pointed out one of my concerns with R2R dacs, that being performance could vary over time as these resistors could drift in value. R2R dacs are reliant on relatively large number of resistors compared to other audio components, so odds of individual resistors drifting over time is more likely. It would be interesting to see a direct comparison of a well used R2R vs. new example of exact same dac. Has the sound quality changed in any way?
My other issue is the quality of those resistors. I've long used point to point wired, minimalist SET amps and pre's, can hear the difference in changing out resistors. I'm sure your listing of tolerances is generally correct, although there are boutique resistors out there that have closer tolerance within a category, such as Takman carbon film.
So my question is, does the quality of resistor make a difference in R2R dac? Take for example, the TotalDac's, which use the Vishay nudes, which are the gold standard for resolution/transparency. I'd expect TotalDac's to outperform R2R dac with lesser resistors. And it should, as the Vishay nudes far, far more expensive than any other resistor.
Based on my observations of R2R, Holo May KTE seems to be highest resolving/transparency for reasonably priced r2r. If Harmony outperforms this pretty good achievement.
Finally, I've found the ESS Sabre dacs I've owned extremely enjoyable, generally these chip dacs are relatively high resolving/transparent. Implementation of these chips is highly variable, these dacs can be extremely musical or irritating depending on that implementation. Anyway, it would be nice to see a comparison of the Harmony to first rate, newer 9038pro ESS chip dac\.
So I'm in market for new dac, this may be contender, although I remain biased against R2R because of the possible resistor issues