Short answer: the NAD C 658, though neither ranks well in its class. It ranks #39 of 43 DAC and headphone amp combos by measured performance, rated 2.8/5, at $2,299. The Ayre Codex ranks #43, rated 1.6/5, at $1,950, $349 cheaper, not enough of a saving to outweigh the sound-quality gap. Both are rated below 3.0/5 among the 43 DAC and headphone amp combos, and the SMSL DO400, ranked #1 at $499, is a better place to start if measured performance matters.
The NAD C 658 is the better-sounding choice. It is a full streaming preamp with Ethernet, Wi-Fi, Bluetooth with aptX HD, two optical and two coaxial inputs, analog RCA inputs and an MM phono stage. The tradeoff: Audio Science Review measured only 90 dB SINAD, so sensitive in-ear monitors may reveal hiss or noise.
Why pick the Ayre Codex: It combines a DAC and headphone amp with USB and optical inputs, RCA and XLR line outputs, and a 6.35 mm jack plus a pair of 3.5 mm jacks usable as a balanced headphone output. Watch for: Audio Science Review measured a SINAD of only 68 dB, a level of noise and distortion that is a real audible weakness, especially with sensitive in-ear monitors.
Buy the NAD C 658. It is rated higher, and the $349 saving on the Ayre Codex is not enough to make up the difference.
Want more options? Browse the full Headphone Amps and DACs rankings.
Specifications Side By Side
| NAD C 658 | Ayre Codex | |
|---|---|---|
| Price | $2,299.00 | $1,950.00 |
| Ranked | #39 of 43 in DAC and Headphone Amp Combos | #43 of 43 in DAC and Headphone Amp Combos |
| Device Type | DAC and headphone amp | DAC and headphone amp |
| SINAD | 90 dB (measured by Audio Science Review) | 68 dB (measured by Audio Science Review) |
| Balanced Output | Yes (XLR line out) | Yes (dual 3.5 mm, XLR line out) |
| Inputs | Ethernet, Wi-Fi, Bluetooth, 2 x optical, 2 x coaxial, 2 x line RCA, MM phono | USB-B, optical |
| Outputs | RCA preamp, XLR preamp, stereo subwoofer | RCA, XLR |
| Bluetooth Codecs | SBC, aptX HD | - |
| DAC Chip | ESS Sabre | - |
| Equalizer | Yes (Dirac Live room correction, bass and treble) | - |
| Dimensions | 17.1” x 3.9” x 15.9” (435 x 100 x 405 mm) | 2.2” x 5.4” x 9.1” (55 x 137 x 230 mm) |
| Headphone Outputs | Headphone jack | 6.35 mm, 2 x 3.5 mm (pair usable as balanced) |
| Volume Control | - | Hardware knob (digital, 1 dB steps) |
| Weight | - | 3.1 lbs (1.4 kg) |
Related Amp and DAC Comparisons
How NAD C 658 compares with other leading options:
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- Essence HDACC II-4K vs NAD C 658
Prices on this page were last checked October 11, 2026 at 4:59 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Amps and DACs In Full
NAD C 658: $2,299.00 Upscale Audio eBay
Pros: It is a full streaming preamp with Ethernet, Wi-Fi, Bluetooth with aptX HD, two optical and two coaxial inputs, analog RCA inputs and an MM phono stage. Dirac Live room correction, stereo subwoofer outputs and XLR preamp outputs make it a flexible hub for a speaker system.
Cons: Audio Science Review measured only 90 dB SINAD, so sensitive in-ear monitors may reveal hiss or noise. NAD doesn’t publish a 32 ohm power figure for the headphone jack, and the SMSL M10 rates higher for far less.
Full NAD C 658 review and specifications →
| Balanced Output | Yes (XLR line out) |
|---|---|
| Bluetooth Codecs | SBC, aptX HD |
| DAC Chip | ESS Sabre |
| Device Type | DAC and headphone amp |
| Dimensions | 17.1” x 3.9” x 15.9” (435 x 100 x 405 mm) |
| Equalizer | Yes (Dirac Live room correction, bass and treble) |
| Headphone Outputs | Headphone jack |
| Inputs | Ethernet, Wi-Fi, Bluetooth, 2 x optical, 2 x coaxial, 2 x line RCA, MM phono |
| Outputs | RCA preamp, XLR preamp, stereo subwoofer |
| SINAD | 90 dB (measured by Audio Science Review) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Ayre Codex: $1,950.00 Ayre eBay
Pros: It combines a DAC and headphone amp with USB and optical inputs, RCA and XLR line outputs, and a 6.35 mm jack plus a pair of 3.5 mm jacks usable as a balanced headphone output. The volume knob steps in precise 1 dB increments.
Cons: Audio Science Review measured a SINAD of only 68 dB, a level of noise and distortion that is a real audible weakness, especially with sensitive in-ear monitors. Ayre does not publish a power figure into 32 ohms, so its ability to drive demanding headphones is unknown. The Pro-Ject Pre Box S2 Digital rates higher and measures far cleaner for much less.
Full Ayre Codex review and specifications →
| Balanced Output | Yes (dual 3.5 mm, XLR line out) |
|---|---|
| Device Type | DAC and headphone amp |
| Dimensions | 2.2” x 5.4” x 9.1” (55 x 137 x 230 mm) |
| Headphone Outputs | 6.35 mm, 2 x 3.5 mm (pair usable as balanced) |
| Inputs | USB-B, optical |
| Outputs | RCA, XLR |
| SINAD | 68 dB (measured by Audio Science Review) |
| Volume Control | Hardware knob (digital, 1 dB steps) |
| Weight | 3.1 lbs (1.4 kg) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons