The audiophile world began reviewing their products in 1991. Audio Note were market changers, designing and building to specifications that were way beyond what was available. Not only do they make the end product, but also make their own custom components available. Ensuring their tube/valve amplifier is working as it should with anode and grid current checks, to make sure they balance. Often problems arise when third party tubes/valves are found to be installed, when AN’s original balanced pairs should be sought.