High resolution, high fidelity and high quality are some typical jargon used in the audio industry, but they truly are essential features for an audiophile. Whilst they look so attractive, they are not so easy to achieve unless the right components are used, especially when there is an additional burden of a design that should be power efficient.
It is customary to use Low Drop Out Regulators (LDOs) for a power efficient system and there are many companies in the world that make these LDOs. The specifications most often focused on while selecting these LDOs are often low noise and high power supply rejection ration (PSRR). However, product designs based on just these parameters don’t really provide the best audio performance and it is essential to also check the Transient Response of the regulator because when the audio equipment changes its operation mode, there could be a change in load demand on the LDO. Digital circuits do not behave favorably to large voltage transients. Analog Devices has some superior transient response LDOs that are best for High Resolution and High Quality products. For example the LT1763, LT1964, LT1965 and LT3015 can help improve the voltage regulation, and eliminate load-transient voltage spikes to provide better audio performance.
Once the power supply is well regulated, less noisy and clean to the desired levels, the next important aspect is the harmonic distortion in the system and there could be many contributors to the total harmonic distortion (THD). Harmonic distortion in audio systems occurs when the original audio signal is distorted by the electronics of the system, resulting in an output audio signal that is somewhat different from the input. Contributors to this distortion exist in the complete signal chain of the application, from amplifiers, ADC, signal processing components, DAC, etc. and the distortion may multiply at each stage of the signal chain. Fortunately, Analog Devices manufactures most of the components in such high-performance audio system signal chains, as shown in the figure below. One critical component in the signal chain is the op-amp that can take inputs from a high-performance DAC and provide an output to the power amplifier, like a unity gain buffer, with lowest distortion. Introduction or addition of any noise or distortion by this buffer stage is highly undesirable. Components like AD826 and LT1364 are best suited for such buffers as the penultimate or ultimate stage of the system.
In this blog we have focused mainly on quality transient response LDOs and low THD amplifiers. In order to achieve the highest sound quality, your high-performance audio will require superior components throughout the entire product signal chain.
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