Originally Posted by Chu Gai
Yes, but what makes anyone think that the others don't? I can have a piece of test or measuring equipment calibrated and certified by an outside company to ensure accuracy as part of an ongoing SQC process. Who is going to certify Vlad's ears and equipment? If he's not feeling well, had a stressful day, is taking meds, or is just experiencing the progressive deterioration of his hearing? What makes him qualified when there is no process in place to confirm and verify that his ears are up to snuff?
When you're selling something, you've got to identify your target audience, find out what you believe it is that resonates with them, and tailor your pitch. If your audience is of the mindset that hearing trumps measurements then that's what you talk about. You tell them how much time you spent selecting this particular type and brand of capacitor because it sounds best when in reality it sounds like the best way to drive sales. You tell them the tubes have been hand selected even though all that means is someone used their hands to take them out of the box. They tell how they go old school and use point to point wiring when in reality their volume means they can't afford an automated robotic process. They tell you whatever it is that you need to hear that resonates with your belief system.
From time to time, you're going to find clunkers on either end of the spectrum. Somebody missed something. They got a batch of whatever and it turns out the manufacturer or their supplier made a change and the capacitors prematurely age. Happens.
With luck, whatever it is you buy at whatever price point will last significantly past the warranty period.
Basically Vlad's ears are important once the design is locked in, then they're only important as a sanity check before shipping.
For example, at many companies the designer listens extensively while designing, and then it's usually someone else at the company (whose ears can be similarly trusted) whose job it is to assure that each unit leaving the factory sounds as close as possible to the original, save factors like break-in.
Test instruments can help in this process so as to not let an obviously broken component reach the listen-before-ship phase, and changes in components would likely be flagged at that stage.
However per usual tests can only find what you're looking for; I recently talked to a person at a company who rejected a preamp before it went out the door because it sounded "weird." It took them about two days to find that one gain stage was misbehaving only when one particular frequency was fed to it, not with pink noise or other frequencies due to a bad discrete part.
The test equipment didn't catch it, the listener did, and now the pre-listen tests include testing for that particular