JCAT Femto USB Card ReviewI build my first music server in December 2013 based on the C.A.P.S. music server. C.A.P.S. stands for Computer Audiophile Pocket Server, a series of projects by Chris Connaker of the Computer Audiophile website (renamed to Audiophile Style). Instead of using the USB output on the motherboard to a DAC, I installed a Paul Pang Audio (PPA) V2 audiophile USB card powered by an 5v Acopian linear regulated power supply. The PPA USB card cost $129.00.
The PPA V2 USB card is based on the NEC uPD720202 chip with a low jitter TCXO and audio grade silver digital output transformer. Paul Pang wrote "Very smooth & analog like but in full audio performance. It is one of the best audio grade usb cards in the world." Back in 2013 the PPA V2 USB card was a very nice card.
I build a faster fanless music server in July 2021 and installed the Paul Pang USB card. The new server with JRiver Media Center sounds exactly the same as the C.A.P.S. server. The faster processor enabled me to ditch JRiver and switch to HQPlayer and upsample all my music to DSD256 which, along with the HoloAudio May KTE DAC, adds depth, a solid center image and eliminates digital harshness. A lot of the sound improvements can also be attributed to HQPlayer's state-of-the-art filters.
https://www.audiocircle.com/index.php?topic=177495.msg1867916#msg1867916I was aware of newer USB cards but prices were always way too high to experiment, the PPA card sounded just fine, how much better could USB sound? I was about to find out.
A used JCAT Femto USB card recently appeared in the AC Trading Post for $325.00, now that was a price I could afford. The JCAT Femto retails for $528. I have been listening to the JCAT for almost a week and the improvement in sound quality is a revelation.
https://jcat.eu/product/usb-card-femto-audiophile-usb-audio-output/top - JCAT Femto card bottom - Paul Pang USB card

My first listening session was a disappointment. There was deeper bass and twinkly highs but the midrange was yuck. Luckily break-in only took a couple of days. The frequency range is now balanced and feels natural. But the JCAT really didn't sound that much different or better than the PPA USB card, that's what happens with quick A-B decisions. I prefer long listening sessions, days or weeks then switch components, sonic differences are then obvious. The longer I listened to the JCAT card the more I realized the sound is a lot more refined than the PPA USB card I had been listening to for 11 years.
The JCAT Femto USB card feels faster, notes start faster with a wider dynamic range. The card isn't analytical but more in tune with how live music is heard. Bass digs deeper and is a little tighter. There is definitely more highs and twinkly stuff that was previously recessed in the mix. Because more of the recording is easily heard the soundstage is wider and the effortless extended lows deepens the soundstage, especially when using a subwoofer. Center images are spot-on and singers appear a little closer to the microphone with song lyrics easier to understand because of the increased clarity.
Not all recordings improve equally. Good but average recordings like the "Million Voices Whisper" by Warren Haynes [24/96] hardly benefit at all whereas "Planet Drum" by Mickey Hart can fill a room with bass drum notes. Where USB cards like the JCAT excel is playing naturally recorded music. Listening to Cat Power Sings Dylan puts me in the third row of the live concert hall recording.
Live, minimally edited true hi-res downloads is where the JCAT Femto really opens up and shows what it can do. Both Sound Liason and 2L - The Nordic Sound record in high resolution, the quality is phenomenal. I buy these recordings whenever I can.
I just bought the remastered Carmen Gomes album "Thousand Shades of Blue - Revisited" in 32 bit/768 kHz even though I have the original 24 bit/96 kHz. I always though the applause sounded brittle on the 24/96 recording, the remix really cleaned up the sound. There is a increase in clarity too, as it should be, the 32/768 download is 16.3 GB. The album is on sale for $14 so the purchase was a no-brainier to try out the new JCAT card. Lower resolutions are available too.
https://soundliaison.com/products/carmen-gomes-inc-thousand-shades-of-blue-revisited
Thousand Shades of Blue - Revisited"Remixing and remastering Thousand Shades of Blue, has been nothing short of transformative. Opening up those sessions felt like traveling back in time, yet with the knowledge and refined sensibilities we've gained. Looking back, we realized just how much our approach to mixing and mastering has evolved. At Sound Liaison, we now embrace a philosophy of minimalism, using fewer tools on individual tracks, preserving the raw beauty of the original performances.
"One of the most striking revelations came when we processed the original tracks through our meticulously crafted analog mastering chain. This system, a labor of love honed over years, gave the music a newfound sense of depth and vibrancy. The spatial arrangement of the musicians on the soundstage became more precise, enhancing the listener's sense of immersion, while the overall presence and authenticity of the sound reached new heights.
"A major decision in our remix process was to eliminate all compressors from the original mix. This approach allowed for more headroom and breathing space, enabling the natural dynamics of each musician to shine in their full detail. The music now flows with an organic energy that captures the intensity and subtlety of every performance.
"We also upgraded the reverb, opting for a refined, state-of-the-art reverb routed through our analog summing mixer to a pristine 32-bit, 768kHz resolution. This enhancement has profoundly opened up the sound, allowing the reverb to integrate seamlessly with the music and bring an extraordinary sense of presence. The reverb now contributes to an even more vivid, three-dimensional soundstage that makes the music feel fully alive.
"Furthermore, we’ve pushed the boundaries of digital fidelity by remastering the album at 768kHz-32-bit, an astonishingly high resolution, over 17 times the standard 44.1kHz used for CD audio. This high sample rate reveals unparalleled harmonic richness and authenticity. While some of these nuances may only be fully appreciated by the most discerning listeners, the enhanced clarity of the soundstage is evident to everyone".
The difference between the JCAT Femto USB card and the Paul Pang V2 USB card is similar to the difference between my old 2012 Ford Focus and my 2023 Subaru Outback, each gets me where I want to go but one is much, much nicer.
Which gets me thinking that another reason audiophiles don't hear much of a difference between standard Redbook files and hi-res is the average quality of the parts in their music servers. Or no quality if using a laptop as a music server. Even my old $129 PPA USB card masked the music's nuances and differences compared to the JCAT card.
Highly recommended.
Wayne