QB9

About the QB9

The Ayre QB-9 USB DAC is a high-performance digital-to-analog converter designed to convert computer audio into high-fidelity analog sound. It uses asynchronous USB transfer mode to minimize jitter, supporting PCM sample rates up to 192 kHz and DSD64 playback. The DAC features a minimum-phase digital filter and single-pass 16x oversampling technology, delivering detailed and natural sound reproduction. It employs zero-feedback, fully balanced discrete circuitry and includes Ayre's proprietary Conditioner power-line RFI filter and AyreLink communication system. The unit offers both balanced (XLR) and single-ended (RCA) analog outputs, with maximum output levels of 4.00 V RMS balanced and 2.00 V RMS single-ended. The QB-9 supports USB 1.1 and USB 2.0 Class 2 Audio modes, with a rear panel toggle switch to select between full speed (Class 1) and high speed (Class 2) USB operation. It is housed in a compact anodized aluminum chassis measuring 8.5" W x 11.5" D x 3" H and weighs 5 pounds. The DAC is noted for its transparent, relaxed sound and ease of setup with Mac and Windows systems, though Windows requires a custom driver for high-speed USB audio beyond 96 kHz. The QB-9 is a USB-only DAC with no S/PDIF inputs, emphasizing purity and simplicity in design.