Why use a USB Audio card?

Why use a specialized USB Audio card when all computers are equipped with USB ports? 

Simply because computers are not designed for low-noise digital playback. While USB ports on all computers must comply with the USB specification, it does not mean they are good for transmitting bits to your USB DAC. Motherboards are filled with noisy switching power supplies. Unless you filter that noise, it will get through to your DAC via a USB cable. A dedicated USB Audio card such as the JCAT FEMTO cancels the noise coming from a PC. The use of filters, ultra-low noise power supplies and extremely precise femto clocking on the card allows for generating a clean USB signal which leads to a much better sound coming out of your DAC.

My DAC has it’s own power supply for the USB input board. It does not use USB power at all – only 1s & 0s are sent, so I shouldn’t be concerned with PC noise at all, right? 

Well, no. The fact that your DAC does not use 5V from USB ports does not change that much. The 1s & 0s are transmitted in an analogue form of electrical voltage signals. And this means that PC noise will travel through USB data signals too and will negatively affect performance of your DAC.

Will I get any benefit from the low-jitter clock on the card if my USB DAC uses Asynchronous USB transfer mode? 

In theory DACs equipped with Async USB input should not rely on a PC clock. But that’s just a theory. In reality, everything on a computer has an impact on sound quality regardless of DAC used. The more resolving the DAC and the hifi system is, the easier it becomes to hear these differences: in software player, PC hardware and even USB cables used for connecting a DAC. The same goes with USB controller chip and its clock oscillator – here is the USB Audio signal generated. The extremely high-precision FEMTO clock on the JCAT USB Card makes sure that the USB Audio stream is sent to your DAC with absolutely no timing errors. Even if your DAC is buffering and reclocking data, you will definitely hear and appreciate the difference. USB output is the only thing your DAC sees. Make sure it is precise. Customers can buy this product in our webshop (click on the banner below).

Marcin Ostapowicz

A recognized high-end audio consultant. Computer audio pioneer. Co-creator of the award-winning software, JPLAY. Manufacturer, curator, and distributor of high-quality audio products. Constantly strives for perfection of sound. Foundations for his breakthroughs finds in areas that others ignore.