For most people, “Do I own the world’s best Ethernet cable?” is probably not a big worry. When plugging in a WiFi router or building a data centre, the best Ethernet cable is any one that works.

Plugging in hi-fi is a whole different game. At the top end, when seeking perfection, no amount of over-engineering can be too much. The best digital audio system deserves a gold-toothed, hand-rolled, snake-oiled cable — maybe because it imparts enigmatic purity to each data packet, but mostly because anything cheaper would represent a compromise.

KJ West One, a London retailer of no-compromise audio equipment, sells an Ethernet cable for £11,200. Though physics cited to justify its price may look a lot like quackery, approached as a luxury good, it’s not out of place.

Every inch of the Marylebone shop is filled with similarly sublime absurdities. There are amplifier stacks the size of filing cabinets and turntables so cunningly counterpoised their makers may as well be promising gyroscopic perpetual motion. Floor-standing speakers resemble retrofuturist coffins, space station cigar humidors or props from an unlimited-budget Doctor Who remake.

We go downstairs to the main listening room, where playing at a volume just below the pain threshold is Deep Purple’s 1972 album Machine Head. It’s the choice of Seva Mikhaylov, a former insurance broker and long-standing customer, who became co-owner almost by accident in 2011 when the business was in trouble.