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So, many audiophiles are convinced that USB cables impact the sound.
The non-believers counter that anything that is entirely digital cannot sound different. It's all 1s and 0s so either the data is bit perfect or it's not and any $10 usb cable is capable of transmitting bit perfect digital data.
Now, one explanation for why a USB cable may sound different (other than placebo) is jitter. USB cables transmitting typical computer file data only are concerned with getting the data from point A to point B, but when the data is going to a DAC chip that must construct an analog signal, timing becomes a critical factor because when the original analog signal is encoded into binary it slices the analog signal at exactly and precisely equidistant points. If you do not reconstruct the analog signal back from digital using the same precise equidistant points then your signal is degraded. This precise reconstruction is highly dependent on the clock being used to time each data point in the digital stream. Any deviation from perfectly timed intervals between data points is referred to as jitter.
But you know all this. But here's the kicker with regard to USB cables, most USB DACSs are immune to jitter introduced by the incoming digital signal. I'm not saying the jitter is low, I'm saying the jitter (data timing irregularities) introduced by the cable is entirely irrelevant because most audiophile USB DACs use an asynchronous USB protocol. What this means is the data is just sent to the DAC and piled up in a buffer in the DAC. Then the DAC uses its own internal clock to read the data as it converts it to analog. This far better because the clock is closer to the DAC chip and distance introduces jitter but also because the clocking done by a typical computer was not designed for the ultra precise process of digital to analog conversion since most digital data that computers transmit is not relying on the integrity of the clock for accurate data transmission. When you copy a file from one place to another, it's going to be digital on both ends, clocking is irrelevant. So, with asynch USB transmission the precise and highly sophisticated on board DAC clock is used. BTW, jitter is still a factor because it can and will be introduced to some extent within the DAC itself as it reconstructs the analog signal from its own data buffer using its own internal clock. But that jitter is likely to be far less.
So in the context of asynch DACS jitter from the USB cable is irrelevant as it cannot impact the sound. Why then would USB cables sound different?
The non-believers counter that anything that is entirely digital cannot sound different. It's all 1s and 0s so either the data is bit perfect or it's not and any $10 usb cable is capable of transmitting bit perfect digital data.
Now, one explanation for why a USB cable may sound different (other than placebo) is jitter. USB cables transmitting typical computer file data only are concerned with getting the data from point A to point B, but when the data is going to a DAC chip that must construct an analog signal, timing becomes a critical factor because when the original analog signal is encoded into binary it slices the analog signal at exactly and precisely equidistant points. If you do not reconstruct the analog signal back from digital using the same precise equidistant points then your signal is degraded. This precise reconstruction is highly dependent on the clock being used to time each data point in the digital stream. Any deviation from perfectly timed intervals between data points is referred to as jitter.
But you know all this. But here's the kicker with regard to USB cables, most USB DACSs are immune to jitter introduced by the incoming digital signal. I'm not saying the jitter is low, I'm saying the jitter (data timing irregularities) introduced by the cable is entirely irrelevant because most audiophile USB DACs use an asynchronous USB protocol. What this means is the data is just sent to the DAC and piled up in a buffer in the DAC. Then the DAC uses its own internal clock to read the data as it converts it to analog. This far better because the clock is closer to the DAC chip and distance introduces jitter but also because the clocking done by a typical computer was not designed for the ultra precise process of digital to analog conversion since most digital data that computers transmit is not relying on the integrity of the clock for accurate data transmission. When you copy a file from one place to another, it's going to be digital on both ends, clocking is irrelevant. So, with asynch USB transmission the precise and highly sophisticated on board DAC clock is used. BTW, jitter is still a factor because it can and will be introduced to some extent within the DAC itself as it reconstructs the analog signal from its own data buffer using its own internal clock. But that jitter is likely to be far less.
So in the context of asynch DACS jitter from the USB cable is irrelevant as it cannot impact the sound. Why then would USB cables sound different?
