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DACs — Ayre Acoustics Codex
Description, images, technical data and specifications
Ayre Acoustics Codex
Image source — © Ayre Acoustics
The Codex is a compact USB DAC, headphone amplifier and preamplifier in one box from Ayre Acoustics of Boulder, Colorado, a company founded in 1993. It took over from the discontinued QB-9 as Ayre's entry-level digital source and sold in the UK for GBP 1,695. Ayre describes it as three components in a single unit - a converter, a headphone amplifier and a line preamplifier for a speaker system - with the switch between headphone and speaker use handled automatically.
Key specs that matter
The converter chip is the ESS ES9018K2M. Over USB the Codex accepts PCM at 44.1 to 384 kHz with 16, 20 or 24 bits, plus DSD64 and DSD128 sent as DoP. The Toslink input takes PCM up to 24 bit and 192 kHz. In DAC mode the fixed rear outputs deliver 4.0 V RMS balanced on XLR and 2.0 V RMS single-ended on RCA. In headphone or preamp mode the maximum rises to 7.2 V RMS balanced and 3.1 V RMS single-ended. The front panel carries one 6.35 mm jack and two 3.5 mm jacks. Power consumption is 28 W, and the case measures 5.5 cm wide, 23 cm deep and 13.7 cm high, weighing 1.4 kg.
Engineering and use context
The analogue stage is discrete, fully balanced and without feedback, and it ends in Ayre's Diamond output circuit, with Equilock circuitry for the active gain devices. A linear AyreLock power supply feeds it. Digital filtering is minimum phase with single-pass 16x oversampling. The USB input uses Ayre's Streamlength version of asynchronous transfer, and Windows computers need Ayre's driver. Volume is set digitally in 1 dB steps from 0 to 100 and keeps full resolution down to -60 dB attenuation. Each mini-jack has its own buffer, so the pair can feed two conventional headphones for shared listening or one balanced headphone through a cable ending in two mini-plugs, chosen in a setup menu. The large jack is wired in parallel with the lower mini-jack. Plugging in a single-ended headphone switches the unit out of balanced mode, which makes the rear outputs incorrect for speakers. In DAC mode, inserting a headphone plug activates the volume control at a preset level of 66. The optical input isolates the audio ground from the connected source. North American buyers who register within 30 days get a five-year warranty.
Pairing
Preamp mode fits systems where the Codex feeds a power amplifier, or powered speakers lacking a volume control, while DAC mode suits a preamplifier. The XLR outputs must not be adapted to RCA inputs.
Alternatives
The Ayre QX-5 Twenty is the brand's larger digital hub with an ES9038PRO converter and ten digital inputs.
Key specs that matter
The converter chip is the ESS ES9018K2M. Over USB the Codex accepts PCM at 44.1 to 384 kHz with 16, 20 or 24 bits, plus DSD64 and DSD128 sent as DoP. The Toslink input takes PCM up to 24 bit and 192 kHz. In DAC mode the fixed rear outputs deliver 4.0 V RMS balanced on XLR and 2.0 V RMS single-ended on RCA. In headphone or preamp mode the maximum rises to 7.2 V RMS balanced and 3.1 V RMS single-ended. The front panel carries one 6.35 mm jack and two 3.5 mm jacks. Power consumption is 28 W, and the case measures 5.5 cm wide, 23 cm deep and 13.7 cm high, weighing 1.4 kg.
Engineering and use context
The analogue stage is discrete, fully balanced and without feedback, and it ends in Ayre's Diamond output circuit, with Equilock circuitry for the active gain devices. A linear AyreLock power supply feeds it. Digital filtering is minimum phase with single-pass 16x oversampling. The USB input uses Ayre's Streamlength version of asynchronous transfer, and Windows computers need Ayre's driver. Volume is set digitally in 1 dB steps from 0 to 100 and keeps full resolution down to -60 dB attenuation. Each mini-jack has its own buffer, so the pair can feed two conventional headphones for shared listening or one balanced headphone through a cable ending in two mini-plugs, chosen in a setup menu. The large jack is wired in parallel with the lower mini-jack. Plugging in a single-ended headphone switches the unit out of balanced mode, which makes the rear outputs incorrect for speakers. In DAC mode, inserting a headphone plug activates the volume control at a preset level of 66. The optical input isolates the audio ground from the connected source. North American buyers who register within 30 days get a five-year warranty.
Pairing
Preamp mode fits systems where the Codex feeds a power amplifier, or powered speakers lacking a volume control, while DAC mode suits a preamplifier. The XLR outputs must not be adapted to RCA inputs.
Alternatives
The Ayre QX-5 Twenty is the brand's larger digital hub with an ES9038PRO converter and ten digital inputs.
Specifications
Model name
Codex
Conversion type
N/A
Engine
N/A
DSD compatability
Yes
Parameters
up to 24 bit / 192 kHz and DSD128
Frequency response low +/- 3dB (Hz)
N/A
Frequency response high +/- 3dB (Hz)
N/A
Gain (dBu)
N/A
Output Level (balanced) (V)
4
Output Level (single-ended) (V)
2
Input Impedance (balanced) (Ω)
N/A
Input Impedance (single-ended) (Ω)
N/A
Output Impedance (balanced) (Ω)
N/A
Output Impedance (single-ended) (Ω)
N/A
Analog outputs
N/A
Signal to Noise Ratio (dB)
N/A
Total Harmonic Distortion + Noise (% at 22 kHz)
N/A
Dimensions (mm)
55 x 230 x 137
Weight (kg)
1.4
Official link
