ЦАПы — Ayre Acoustics QA-9 Pro

The QA-9 Pro is an analogue-to-digital converter, not a DAC, from Ayre Acoustics of Boulder, Colorado. It takes a line-level analogue signal and turns it into digital data for a computer or recorder, for tasks such as archiving vinyl and tape, recording, mastering and product development. The QA-9 comes in two versions covered by one manual - the standard unit with USB and AES/EBU outputs, and the Pro, which adds DSD and word clock outputs for studio use.

Key specs that matter

A pair of balanced XLR inputs presents 2 Mohm, or 1 Mohm per phase, and Ayre supplies adapters for single-ended sources. Input sensitivity runs from 10.0 V RMS at minimum gain to 0.75 V RMS at maximum. Over USB 2.0 the Class 2 mode delivers 44.1 to 192 kHz at 24 bits and the Class 1 mode 44.1 to 96 kHz. The AES/EBU output on a 110 ohm transformer-isolated XLR covers the same six rates up to 192 kHz. The Pro version's DSD output runs at 64x, 128x or 256x the CD rate. Frequency response reaches DC to 20 kHz at 44.1 kHz, DC to 66 kHz at 192 kHz and DC to 80 kHz at DSD256. The chassis measures 21.5 cm wide, 29 cm deep and 7.5 cm high, weighs 2.3 kg and draws 25 W.

Engineering and use context

Ayre builds the input electronics from discrete parts in a fully balanced, zero-feedback layout, with its Equilock circuitry for the gain devices. Its variable gain lets the full range of each source reach the converter, set with the front knob in twelve 2 dB steps. Bar-graph meters on each side of the display show how much of the digital range each channel uses, and the top red segment holds for ten seconds after clipping. Opto-couplers isolate the computer connection electrically to keep its radio-frequency interference out of the audio system. A rear switch chooses between two PCM filter algorithms, Listen for time-domain accuracy and Measure for frequency-domain accuracy. The DSD output uses Sony's single-bit format over SDIF-2 or SDIF-3 on 75 ohm transformer-isolated BNC jacks, with SDIF-3 unavailable at 256x. Word clock outputs carry TTL-level signals from the internal master clock, so studio equipment can be slaved to the converter. When USB is connected, the AES/EBU output is disabled.

Pairing

A phono stage, tape deck or mixing desk feeds the XLR inputs, and the USB output connects to a computer running archiving or recording software such as Vinyl Studio, Pure Vinyl, Audacity or Pro Tools.

Alternatives

The standard Ayre QA-9 is the same converter without the DSD and word clock outputs.