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About opus101

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  1. Not really that odd - good numbers on a DAC attracts customers who tend towards the view that a DAC with outstanding measurements is essentially transparent. Hence nothing to talk about.
  2. Personally I prefer a slightly more nuanced version - 'everything matters but to differing degrees, including infinitesimally small'. I would agree that many 'subjectivist' mindsets don't seem to have the concept 'low-hanging fruit'. I also prefer 'show' to 'tell' but for me, ASR leans too far in the direction of the latter. The corollary of 'show' to me is observe and observations have quality. Numbers don't. Incidentally @JoshM I think the reason they keep on measuring DACs is because its popular. Going back a couple of years, ASR didn't seem to me to be adding many new members. After Amir got his brand new AP it really picked up and now has become a honeypot for numbers guys.
  3. If you ask them for a falsifiable definition of 'properly engineered' you'll never get one. Sometimes 'competently' is used instead of 'properly' but the intent is the same. A more nuanced mantra is 'All competently engineered DACs sound identical under level matched, double blind conditions'.
  4. Looks once again that you've missed the point. See if you're any wiser after reading this article on Goodhart's Law : https://adexchanger.com/data-driven-thinking/what-goodharts-law-can-teach-you-about-performance-data/
  5. Looks like dodgy reasoning to me. When people target a particular distortion metric, that particular metric ceases to be one guaranteeing a good outcome for customers.
  6. Summed up in Goodhart's Law : When a measure becomes a target, it ceases to be a good measure.
  7. Even the very latest AKM DAC (AK4499) has only -100dB stop-band rejection. Also note it uses an equi-ripple filter. These are known to exhibit pre-echoes - see a paper on this by Julian Dunn. http://www.nanophon.com/audio/antialia.pdf
  8. Thanks - I should have added that there's no speaker protection on these so I would recommend either using only cheap speakers or find a protection module to strap on the output.
  9. I don't know if classD amp cards come within the remit of this thread (delete this if not) - if so I'd like to give a shout-out for these highly affordable ($11) mono amp modules. https://item.taobao.com/item.htm?spm=a230r. They don't come with input buffers (Zin ~3.3kohm) and you do need to supply a balanced power supply. Its a very low-cost route to respectable classD sound - you can tweak the card fairly simply to get what I consider to be high-end sound.
  10. Since the topic of input filtering has already come up on this thread, here's something about aliasing from OOB input signals : https://www.diyaudio.com/forums/class-d/321632-hypex-ncore-nc400-input-anti-alias-filter.html
  11. For some reason I can't quite believe that claim.
  12. Clearly this document's going to come in above your pay-grade but others might find it relevant : http://www.ti.com/lit/an/snoa497b/snoa497b.pdf
  13. I see no reference to DECT there. Handphones of course existed prior to the establishment of DECT standards.
  14. Well it is true I only scanned the Wikipedia article. But now I've had more time to look through it, I am seeing things like : Before 1.9 GHz band was approved by the FCC in 2005, DECT could only operate in unlicensed Region 2 2.4 GHz and 900 MHz ISM bands A cite for your 30MHz claim would be useful.
  15. I had a quick look at Wikipedia on DECT, didn't see any mention of DECT going that low in frequency. In my understanding its >900MHz but you're a telecoms guy, feel free to educate me.
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