At OA21 we only use parts that do not fail OUR tests spec sheets mean nothing , Then we listen to every single part. Components used in OA21 amplifiers has never failed and will last for decades.
After 35 years one simple sentence has taught us many lessons: "Specification subject to change without notice". When we design a component or a system for use of that component, we test it, we listen to it and then we dissect it.
We see how every component is made, we see what it's made from, we make sure that every component that we use is only used to 50% of its working limit. The cost of this basic design principle is normally halved by other companies for the sake of profit. We refuse to compromise, reliability and longevity for these predominantly cost savings. Every component is inspected and rejected if does not meet our requirements.
We test every single part before we allow its use. We establish its manufacture process, its material content, its origin of manufacture (where it's made), its destruction limit and more importantly than any of this... how it sounds when we use it. Every product we have ever sold before it is released for sale, is tested to establish the abuse it can take and the result of failure.
Our tests include undergoing extreme loads of temperature - up to 145 degrees Celsius. In many cases we halted the tests when the adhesive pads of the rubber feet started to melt. OA21 amplifier continued to perform without any degrade of performance. No consumer environment would ever exceed this test.