Toroidal transformer
The presence
of a toroidal transformer in the design of the device.
Such a transformer has a core in the form of a toroid (ring). It is believed that such a design reduces the level of extraneous electromagnetic radiation and minimizes the likelihood of interference from the transformer.
DAC
Model of the digital-to-analogue converter installed in the device.
DAC in this case means the “heart” of the device, the main circuit that directly provides the conversion of digital audio to analogue. The name of the DAC model is given mainly for advertising purposes — as an illustration of the fact that high-quality components are used in the device. In addition, knowing the model, you can find detailed information about a particular DAC; although in fact such a need does not arise often, it may still arise in some specific cases.
DAC sampling frequency
Sample rate of the digital-to-analogue converter used in the device.
DAC in this case means the “heart” of the device, the main circuit that directly provides the conversion of digital audio to analogue. And the sampling rate is initially one of the characteristics of digital sound. In this case, its meaning is as follows: the sampling rate of the DAC must not be lower than the corresponding indicator in the incoming audio signal, otherwise the device will not be able to effectively cope with the conversion.
Frequency range
The audio frequency range supported by the device. Most often, we are talking about the frequency range that the device can output in an analogue audio signal at the output.
In general, the wider the frequency range — the fuller the sound, the lower the likelihood that the transducer will “cut off” the upper or lower frequencies. However, note that the human ear is able to hear sounds at frequencies from 16 to 22,000 Hz, and the upper limit decreases with age. So from a practical point of view, it does not make sense to provide a wider range in audio technology. And the impressive numbers found in high-end devices (for example, 1 – 50,000 Hz) are more of a "side effect" of advanced electronic circuits and are given in the characteristics mainly for the purpose of advertising. Also recall that the overall sound quality is affected by many other factors, in addition to the frequency range.
Signal to noise ratio
The signal-to-noise ratio provided by the converter.
This parameter describes the ratio of the volume of the pure sound produced by the device to the volume of its own noise (which is inevitably created by any electronic device). Thus, the higher the signal-to-noise ratio, the clearer the sound, the less the DAC's own noise affects the audio signal. Indicators up to 80 dB can be considered acceptable, up to 100 dB — not bad, 100 – 120 dB — good, more than 120 dB — excellent. However, it is worth remembering that the overall sound quality is affected not only by this parameter, but also by many others.
Note that the signal-to-noise ratio is often associated with such a characteristic as the dynamic range (see above). They are similar in general meaning, both describe the difference between an extraneous background and a useful signal. However, the noise level in the calculations is taken differently: for the signal-to-noise ratio, the background of the converter “at idle” is taken into account, and for the dynamic range, the noise that occurs when a low-level signal is output. This is the reason for the difference in numbers.
Coef. harmonic distortion
The coefficient of harmonic distortion produced by the converter during operation.
The lower this indicator, the clearer the sound produced by the device is, the less distortion is introduced into the audio signal. It is impossible to completely avoid such distortions, but it is possible to reduce them to a level that is not perceived by a person. It is believed that the human ear does not hear harmonics, the level of which is 0.5% and below. However, in high-end audio applications, distortion rates can be much lower — 0.005%, 0.001% or even less. This makes quite a practical sense: the distortions from the individual components of the system are summed up, and the lower the harmonic coefficient of each component, the less distortion there will be in the audible sound as a result.
Input sensitivity (RCA/XLR)
Input sensitivity of the RCA and/or XLR inputs provided in the device.
See below for details on the inputs themselves. And input sensitivity is the smallest average (rms) signal level at the input that the device can normally accept and process. Compatibility with external analogue signal sources depends on this indicator: the output voltage of the source must not be lower than the input sensitivity of the converter, otherwise normal sound processing will be impossible. However, you should not allow a significant excess of the input signal level over sensitivity, otherwise overloads are possible. These points are described in more detail in special sources.
Input impedance (RCA/XLR)
The impedance of the RCA and/or XLR inputs provided by the device.
For the inputs themselves, see below. And impedance is called dynamic resistance — resistance to alternating current (such as an audio signal). In general, it is believed that the higher it is, the better the device is and the less distortion it introduces into the signal; however, there are certain nuances, they are described in detail in special sources. The standard value is considered to be 10 kOhm, however, there are models with both higher and lower input impedance.
Output voltage (XLR)
The output voltage provided by the device on the XLR outputs.
See below for more details on these outputs. And compatibility with an external amplifier or other analogue audio receiver depends on this indicator: the output voltage of the DAC must not be lower than the input sensitivity of the receiving device, otherwise the latter will not be able to process the sound normally.
