How do you know the percentage of improvement? Or what is the formula? How to get that?
Understanding and recognizing small differences between a good and a better amp may be difficult and may require trained ears. But even untrained ears can certainly hear and understand the 'large' differences that are supposed to be there to justify the large price difference.
Take a Ahuja and a Marantz - everyone can hear the difference. Take a NAD and a Marantz, and the going gets more difficult. But what I am saying here is this. Take a Ayre AX-5 at $10,000, and a Audio Note Jinro at $26,500, you will be hard pressed to find differences and pin them down.
Read what Stereophile has to say about each.
"The AX-5 offered a combination of incisive detail, perfect musical timing and momentum, and naturally warm timbral colors, said AD. "It's one of the three best, most musical, most human-sounding solid-state amps I've ever heard," he concluded. "Its wide bandwidth and low distortion are a testament to the intrinsic linearity of the diamond circuit," added JA.
"Though its midrange was a bit soft, the Jinro showcased powerful bass, unsurpassed flow and momentum, and an overall sound that was very subtly sweet. AD concluded: "The Jinro exists as an appealing alternative for those who can appreciate and afford such a thing: a wonderful, wonderful amplifier."
And, read what they say about the NAD C 316BEE at $379.
"The NAD matched power with grace, providing a rich, forceful overall presentation and an impressive ability to follow complex musical passages and make clear, truthful distinctions among musical instruments."
This is where I am saying the difference between three products priced at 400, 10,000 and 26,500 MAY not justify the price differences.
As DilliHiFi said, brand awareness and branding could play a role. But the delivery certainly does not justify the price difference. At least in my opinion.
Cheers