Measurement and analysis techniques in RAA are constantly evolving. The main task of numerous measurements is not to find the best product in the world. We are developing the ability to compare products and are searching for parameters that can directly tell about the quality or features of the sound of the product.
One of the important parameters of the amplifier is its output power.
First, the power was determined from the point of the amplifier's transition into clipping. But we are interested in comparing amplifiers not only in terms of level when we hear an obvious wheeze. We are interested in comparing the power of amplifiers when they operate in high quality mode.
In many amplifiers, the transition point to clipping is the change in the character of the spectrum in the form of rapid growth of high order harmonics. There are amplifiers whose harmonics of high order grow with increasing signal level not too fast. To differentiate between different modes at the end of 2015, three variants were used: "clean", "optimal" and "maximum" on the verge of clipping.
When there are numerous tests of various amplifiers, different dependencies become apparent. from the pure mode to the optimal mode and the clipping mode can be described by several values of the voltage and current at which the spectra change in character.
Previously, voltage, current and power curves were constructed at different times with an approximate representation of what kind of spectrum belongs to the pure, optimal and maximum mode. The power results were not quite comparable for comparisons.
Reports in the RAA contain full data on the spectra of the amplitudes. This allowed us to determine more precise criteria for determining the types of spectra characters and to update the graphs of the maximum voltage, current and power. This is a big plus of the RAA approach with the availability of detailed reports.
In the new methodology for plotting, instead of the three modes, four modes are defined.