When considering the purchase or selection of electronics, power ratings play a crucial role in a consumer's decision-making process. However, the power output ratings of amplifiers and receivers may not be as straightforward and reliable as they initially appear. Most manufacturers adhere to the FTC standard test conditions which state:
(c) The amplifier shall be preconditioned by simultaneously operating all channels at one-eighth of rated power output for one hour using a sinusoidal wave at a frequency of 1,000 Hz;
Although the above guideline from the FTC aims to create a standardized way to compare apples to apples, it in fact leaves the door open for impressive on-paper specs without regard to real-world performance.
At NAD, we are deeply committed to providing prospective buyers with the most accurate understanding of our product's capabilities. To achieve this goal, we have developed our proprietary power rating system known as 'Full Disclosure Power' (FDP). The FDP standard is NAD’s direct response to the FTC standards, because we felt that measurements were only meaningful when tested under real-world listening scenarios. Below are four fundamental aspects to consider when evaluating FDP.
1) Specified within Rated Distortion
At NAD, we take pride in adhering to a stringent policy of specifying our designs within rated distortion. For instance, if our amplifier has a specified distortion of 0.03%, we ensure that the measurement precisely aligns with this figure (300th of a percent). Other brands might opt for a much higher distortion rate (typically 1% but 10% isn’t uncommon) to squeeze out a few additional watts and power from their units. However, without a careful examination of the fine print, unsuspecting buyers may be misled. For example, our commitment to transparency and accuracy is the driving force behind the development of Full Disclosure Power as our unique power rating standard.
2) Full Frequency Band Measurement
Full Disclosure Power stands apart from other industry ratings due to our rigorous measurement approach. When rating our receivers, we subject them to a demanding 4-Ohm load with all channels driven simultaneously, covering the entire frequency bandwidth from 20Hz to 20kHz, all at rated distortion. This contrasts significantly with the minimal requirements set forth by the FTC, which specifies an 8 Ohm load, a single channel, and a much simpler 1 kHz frequency with no distortion specifications. By measuring over the entire frequency spectrum, from 20 Hz to 20 kHz, we ensure a comprehensive assessment that accurately reflects the amplifier's capabilities across the full audio spectrum.
3) Consistent Measurement at Eight Ohms
To maintain consistency, NAD Electronics employs the widely accepted industry standard of measuring all our components at eight ohms. Some manufacturers may deviate from this standard, adjusting the load to maximize output, for example, by measuring at six ohms. Such deviations make it challenging to compare specifications accurately, often leading to misunderstandings for consumers. As it so happens, NAD also specifies into 4 ohms, a much more demanding, difficult load. At NAD, we prioritize transparency and reliability by adhering to the universal eight ohms standard.
4) Measurement with All Channels Driven
When assessing AV receivers with multiple channels, it is essential to understand the testing conditions thoroughly. Many brands measure only one or two channels, neglecting the others, which may not present a comprehensive representation of the amplifier's true capabilities. However, at NAD, we conduct our measurements with all channels driven simultaneously. This approach accurately reflects the strain on the power supply when all channels operate at their maximum potential. A comparison based on these measurements offers a more reliable understanding of an amplifier's performance.
Image showing T 758 V3i Front & Back
