Dispatch by DHL, from Taiwan to rural Ireland via three flights, took 5 days including a weekend. A quick word on switch-mode power supplies. Just like switching output stages aka class D, they can suffer a poor rep depending on who does the talking. Chord and Linn have built entire catalogues around them. Nagra's Classic Amp uses one. So does our Crayon CFA-1.2. For the first generation, Crayon outsourced theirs from Traco. The current deck runs a shielded Mean Well from, yes, Taiwan. Categorical rejection of switch-mode tech seems as off colour as identifying nationalities by food which once upon a time turned Germans into krauts, French into frogs, British sailors into limeys, Mexicans into beaneys, Dutch into cheese heads and Koreans into kimchi. Not only is such language offensive, it's perfectly silly. Not every German enjoys Sauerkraut; not every Frenchman eats frog legs; and chefs, shops and eaters outside these countries embrace such specialty foods.

Still, generalizations abound. In hifi, one of them is that linear power supplies are superior. I've seen compelling arguments for and against them just as I've seen others for and against SMPS. In the end, implementation wins. In a headphone amp, we don't need massive current but ultra-low noise. Clearly the COS engineers felt that this type power supply best met their needs; and that their chosen vendor already had a better solution than they could roll; or do as cost effectively. A designer's job isn't always to reinvent the wheel. It's to identify which parts best arrive at the desired end. The same goes for operational amplifiers aka on-chip amps. Many years ago Junji Kimura of 47Labs upset the high-end industry by launching a not cheap amp based on 'lowly' op-amps outputs. Today Hong Kong's Clones Audio still carry on that torch. As a matter of differentiation (most of it hasn't the resources to design and fabricate their own opamps) high-end hifi luvs discrete but digital is an exception. Even luxo DACs may use ICs without risk of getting ostracized. Still, discrete R2R ladders are becoming popular as chipless distinction.