3 years after the release of the first revision of the JCAT USB Card, designed to enhance USB Audio playback experience with desktop PCs, we proudly present its successor – the JCAT USB Card FEMTO.

Even though the performance of the original JCAT USB Card was excellent and by many customers and professional reviewers considered best on the market, our endless pursuit of quality led us to new developments that set the bar at the level we have never thought would be possible with computer based USB Audio playback.

hi-end audiophile pcie usb audio output card with femto clock

hi-end audiophile pcie usb audio output card with femto clock

FEMTO Clock Technology

We have found that the quality of clock used for generating USB Audio signal at PC side is as important for sound as the quality of clock in DAC. Therefore for the new revision of the JCAT USB Card we incorporated one of the finest clock oscillators available, Crystek CCHD-957 which has been designed specifically for High Definition Audio. It features a typical low close-in phase noise of -100 dBc/Hz @ 10 Hz offset, and a noise floor of -169 dBc/Hz. With this extreme low phase noise performance, you will “Hear the Difference”. The Crystek Femto Clock which is located just a few millimeters away from the USB controller chip is powered by a dedicated ultra-low noise linear regulator for maximum performance.

Ultra low-noise regulation

In the previous revision of the JCAT USB Card, the USB controller’s digital core 1V power was supplied from the PC via PCI Express lane. We redesigned the card so that all internal circuits are powered by ultra-low noise linear regulators exclusively if any 5V power supply is connected (either external or internal).

audiograde pcie usb audio output card with femto clock

hi-end audiophile pcie usb audio output card with femto clock

External PSU option

Although the USB Card FEMTO will operate without 5V for self-powered USB devices, the best performance can be achieved with an external high quality 5V power supply. You can use the 200W linear power supply from our JCAT shop or some other high quality linear or battery 5V PSU.

hi-end audiophile pcie usb audio output card with femto clock

If high quality 5V PSU is not available please connect internal computer power supply to the LP4 connector on the card and switch jumpers J5 & J7 from default position 1-2 to position 2-3. By default the jumpers on the card are configured to use external PSU via DC jack connector on the PCI-e bracket next to the two USB ports on the card. If PSU is not connected then it is impossible to filter well.

JCAT USB Card FEMTO can benefit additionally from full galvanic isolation provided by our JCAT USB Isolator. We recommend using JCAT USB Cables for best sound quality.


  • Audiophile USB Audio output for USB DACs & USB-to-S/PDIF converters
  • Ultra low noise design for high definition audio playback
  • Ultra low noise linear regulators and high quality filters designed to eliminate noise interferences from PC
  • Femto Clock Technology (Crystek CCHD-957) lowers jitter below measurable levels
  • uDP720201 NEC controller
  • High durability gold plated USB 3.0 connectors from Amphenol
  • Two USB 3.0 connectors supporting Low Speed (1.5 Mbps), Full-Speed (12 Mbps), Hi-Speed (480 Mbps) and Super-Speed (5 Gbps) data rates
  • 5V PSU can be supplied from computer PSU via LP4 connector or from an external PSU via 2.1/5.5mm center positive DC jack connector (our 200W linear PSU recommended for best SQ)
  • Both full-size and low-profile PCI-e brackets included


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