USB-Interface

Modern USB audio interfaces are USB audio class 2 compliant.

Asynchronous mode, external clock and galvanic isolation are the things to look for.

Amanero OEM Combo384 Module € 79

OEM Combo384 Module - USB class 2 to I2S 32bit and DSD output Converter

Supported Sample Rates: 44.1Khz 48Khz 88.2Khz 96Khz 176.4Khz 192Khz 352.8Khz 384Khz Output Format: I2S 32bit and native DSD 2.8224 Mhz - 3.072 Mhz - 5.6448 Mhz - 6.144 Mhz Oscillators: 2 Low Phase Noise TCXO

Dimension 30x69mm

Note DSD output enable line to signal an incoming DSD stream.

The card supports output mode only.

NO Drivers needed for Mac OSX 10.6+ and Linux with UAC2 compliant kernel KS/Wasapi/Direct Sound Drivers for MS OS Xp to Win8 32-64bit included at no fee.

XMOS XS1-L1 USB Audio 2.0 US$ 149.00

One of the most popular brands.

USB endpoints use the asynchronous synchronization
500 MIPS, 8 threads, XS1-L1 processor
2 Channel analog input
2 Channel analog output
USB 2.0 high speed interface - supports multiple 24 bit, 192kHz channels with extremely low latency (3ms round trip)
Plug-and-play with Audio Class 2.0 enabled computers (native Mac OSX support, Thesycon Windows drivers available)
Audio Class 1.0 compliant - native Mac OSX and Windows support
Asynchronous clocking - complete control of the audio master clock

Basically a USB to I2S converter. Optional support for SPDIF/ADAT/MIDI

Luckit WaveIO €99.00

Asynchronous USB-to-I2S interface

USB Audio Class 2 compatible
Low latency (sub 3µs in the best case)
16 to 24 Bit-transparent reproduction
44.1 to 192 kHz standard sample rates supported
Built with XMOS processor running @ 500 MIPS

Driver Support:

No drivers needed for MAC OS version 10.6.4 and above
No drivers instalation required for Linux with UAC2 compliant kernel
ASIO/KS/WASAPI/Direct Sound drivers for Windows XP to 7 (32 and 64 bit)
Fully featured Thesycon driver package (without 30 min. periodic beeps)

PCI to USB Cards

Everybody a bit familiar with digital audio knows jitter.
This is a “problem” when doing AD or DA conversion.
Sound quality improves if the jitter is low.
But does it help to have a USB bus driven by a low jitter clock?
Positive testimonials by the number, that is inherent to listening with one’s eyes.
Objective evidence? None.
Don’t waste your money on a audiophile USB card.

JCat USB Card €397.00

ultra low noise design for noise sensitive audio applications
ultra low noise linear regulators and high quality filters
high precision ultra low phase noise oscillator
uDP720201 NEC controller
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 for USB devices can be supplied from a PC’s power supply via an HDD LP4 connector or from an external power supply via a power jack connector
for noise sensitive applications the 5V USB power can be filtered by two onboard high performance filters with PSRR better than 90dB at 10kHz
in case external PSU is of very high quality, it is possible to bypass the filters and pass 5V USB voltage from the external PSU directly to the USB connector
for self-powered USB devices a 5V power is not required for the card operation

Added 1/2015

SOtM tx-USB US$ 300

A audiophile PCI to USB card with ultra low noise regulator for digital, clock, PLL and USB power circuit and ultra low jitter clock for USB clock.

Compliant with USB 2.0
All ports can handle high-speed (480 Mbps), full-speed (12 Mbps), and low-speed (1.5 Mbps)
32-bit 33 MHz host interface compliant with PCI specification revision 2.2

PPA Studio TOP GRADE USB 3.0 CARD US$ 169

NEC uPD720200 chip with low jitter TCXO and output transformer.

The Well-Tempered Computer