The NAD C658 is a streaming DAC (Digital to Analog Converter) pre-amp designed for critical stereo listening. Built into it is the BlueOS streaming advanced operating system. This software allows you to access and stream lossless music up to 24-bit/192kHz to any room using your home’s network. 

One thing that makes this amp cool is NAD’s upgrade path. To update the software on this unit and do HDMI switching, you’ll need the MDC (Modular Design Construction). On the back of the C658, there are two empty slots for the MDC to go in. Think of it like a PC where you can put in a different video card. This advanced technology makes this unit 4k capable and has 3 HDMI in and 1 HDMI out port.

Having a dedicated preamp like the NAD C658 solves my/your HDMI issue in the instance where we want to run a display without having to go with a full-blown home receiver. What we did with John’s garage in Atlanta was connect this unit to the Dynaudio Core Studio Monitors that have the amplifiers built into them. 

The C658 also features Dirac Live room correction. This software prioritizes the speaker's impulse response alongside its frequency balance in the room - improving the imaging of your sound system and the clarity of your music.

Here’s what my setup looks like:

• NAD C658
• x2 Dynaudio Core Studio Monitors
• x2 Dynaudio Core Bracket
• x2 DynAudio Core Subs
• x2 XLR Cables
• x2 RCA XLR

I get that this may be overkill for most people, but it’s what I wanted, and it looks/sounds freaking amazing.

Specifications

• THD (20Hz – 20kHz) | <0.005% at 2V out
• Signal-to-Noise Ratio | >106dB (IHF; A-weighted, ref. 500mV out, unity gain)
• Channel separation | >80dB (1kHz) >70dB (10kHz)
• Input impedance (R and C) | 22 kohms + 100pF
• Maximum input signal | >4.5Vrms (ref. 0.1% THD)
• Output impedance | Source Z + 240 Ohm
• Input sensitivity | 93mV (ref. 500mV out, Volume maximum)
• Frequency response | ±0.3dB (20Hz – 20kHz)
• Maximum voltage output – IHF load | >4.5V (ref. 0.1% THD)
• Tone Controls Treble | >±7.0dB at 20kHz; Bass: ±7.0dB at 60Hz; Balance: -10dB

Phono Input, Audio Pre-Out:

• THD (20Hz – 20kHz) | <0.01% at 2V out
• Signal-to-Noise Ratio | >84dB (200 Ohm source; A-weighted, ref. 500mV out) | >76dB (MM cartridge source, IHF; A-weighted, ref. 500mV out)
• Input sensitivity | 1.44mV (ref. 500mV out, Volume maximum)
• Frequency response | >±0.3dB (20Hz – 20kHz)
• Maximum input signal at 1kHz | >80mVrms (ref. 0.1% THD)

Line Input, Headphone Out

• THD (20Hz – 20kHz) | <0.005% at 1V out
• Signal-to-Noise Ratio | >110dB (32 Ohms loads; A-WTD, ref. 2V out, unity gain)
• Frequency response | ±0.3dB (20Hz – 20kHz)
• Channel separation | >>60dB at 1kHz
• Output impedance | 6 Ohms

DAC

• Supported audio file formats | MP3, AAC, WMA, OGG, WMA-L, ALAC, OPUS
• High-resolution audio formats | MQA, FLAC, WAV, AIFF, Supports converted DSD playback via the BluOS desktop app (only)
• Native sampling rates | up to 32bit/192kHz
• Bit depths | 16 – 24

BlueOS

• Supported operating systems | Plays music from network shares on the following desktop operating systems: Microsoft Windows XP, 2000, Vista, 7, 8 to current Windows Operating Systems and Mac OS X versions
• User interface mobile operating system | BluOS – Free Android and iOS App available online at Google Play and Apple App store
• Supported cloud services | Spotify, Amazon Music, TIDAL, Deezer, Qobuz, HDTracks, HighResAudio, Murfie, JUKE, Napster, Slacker Radio, KKBox, Bugs
• Free internet radio | TuneIn Radio, iHeartRadio, Calm Radio, Radio Paradise
• Bluetooth quality | Bluetooth aptX HD wireless built-in
• Bluetooth connectivity | Two-Way (Transmit and Receive)
• Network connectivity | Gigabit Ethernet RJ45 | WiFi 5 (802.11 ac/n)

Dimensions and Weight

• Dimensions (W x H x D)** | 435 x 100 x 405mm (17 1/8 x 3 15/16 x 16)
• Shipping Weight | 10.1kg (22.3lb)

FAQ

C658 Data Sheet

NAD C658 Owner's Manual
BluOS Streaming DAC
6' AC power cord
Remote control (SR9)
2 "AA" batteries
2 Antennas
Auto calibration microphone
USB microphone adapter
Quick Setup Guide
Internet Update Guidelines
Warranty Card
BluOS brochure
Dirac Live brochure

Ships from OGHQ Warehouse. Shipping costs are calculated at checkout. Our audio solutions will be fulfilled as products are available, so shipments might be delayed. Audio products are subject to a 15% restocking fee.

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