Unison Research Unico CD Due CD Player and DAC at Vinyl Sound Buffalo, NY USA

The Unico CD Due is a flagship CD player and DAC from Unison Research (Treviso, Italy), available at Vinyl Sound in Buffalo, NY, USA. Combining an ESS Sabre ES9018K2M DAC with a jitter eliminator, four ECC83 tubes in a pure Class A differential totem-pole output stage, and a comprehensive digital input array, the Unico CD Due bridges the CD format and the full breadth of contemporary digital audio. Its USB input accepts 32-bit PCM up to 384 kHz and DSD64/128/256, while S/PDIF, AES/EBU, and Toslink inputs cover every source component standard in current use. The ESS Sabre ES9018K2M DAC achieves a signal-to-noise ratio of 125 dB and a THD+N of 0.0003% at 0 dBFS. An optional solid-state output buffer (AD8597/AD8599) can be engaged by remote control for a low-impedance output alternative to the valve stage.

ESS Sabre DAC with Tube Class A Output Stage

The Unico CD Due's digital-to-analog conversion is handled by the ESS Sabre ES9018K2M -- an eight-channel DAC chip used in a stereo configuration and equipped with ESS's proprietary Hyperstream architecture and jitter eliminator. The IV (current-to-voltage) conversion stage uses AD8597/AD8599 op-amps -- ultra-low distortion, ultra-low noise operational amplifiers selected for their performance in high-precision audio conversion applications -- with Wima capacitors and Vishay resistors throughout the signal path. From the IV stage, the audio signal passes into a four-ECC83 tube output stage configured as a differential totem-pole operating in pure Class A. This tube output stage is responsible for the Unico CD Due's tonal character: the ECC83's Class A triode operation adds a warmth and dimensionality to the DAC's inherently precise conversion. A 128 x 64 white OLED display, dimmable to off, provides playback status and source selection information.

Comprehensive Digital Connectivity

The Unico CD Due's input complement covers every contemporary digital connection standard. USB operates at 32 bits and accepts PCM from 44.1 kHz to 384 kHz as well as DSD64, DSD128, and DSD256 in asynchronous USB 2.0 Audio Class mode. The S/PDIF coaxial input (75 ohm, 0.5 Vpp) accepts PCM up to 192 kHz and DSD64 via DoP. The AES/EBU balanced digital input (110 ohm, 2 Vpp) accepts the same PCM range. The Toslink optical input accepts up to 96 kHz natively (higher rates with suitable transmitters). A Bluetooth receiver (BT 3.0, A2DP profile) enables wireless streaming from smartphones and computers at 44.1/48 kHz. Digital outputs -- S/PDIF coaxial and AES/EBU -- allow the CD Due to serve as a standalone transport driving an external DAC. RCA stereo and XLR stereo analog outputs are both provided.

Key Features

• ESS Sabre ES9018K2M DAC: Reference-grade DAC chip with 125 dB SNR and 0.0003% THD+N, low phase-noise crystal oscillators, and integrated jitter elimination.
• Four ECC83 Tube Class A Output Stage: Differential totem-pole tube output stage in pure Class A provides the analog warmth and dimensionality characteristic of Unison Research's valve engineering philosophy.
• USB up to 32-Bit / 384 kHz and DSD256: Asynchronous USB 2.0 Audio Class input supporting every current high-resolution PCM and DSD format.
• AES/EBU Balanced Digital Input: Professional-standard balanced digital input for connection to studio-format sources and high-end CD transports.
• RCA and XLR Analog Outputs: Both unbalanced RCA and balanced XLR stereo analog outputs are available simultaneously.
• Bluetooth BT 3.0 with A2DP: Wireless streaming from smartphones and computers at standard resolution.
• Optional Solid-State Output Buffer: AD8597/AD8599 buffer can be engaged by remote control to bypass the tube output stage for a low-impedance, solid-state-characterized output.
• OLED Display: 128 x 64 white OLED display with dimming to off for unobtrusive operation in darkened listening rooms.

Digital Input Specifications

• USB: 32-bit, 44.1 / 48 / 88.2 / 96 / 176.4 / 192 / 352.8 / 384 kHz PCM; DSD64, DSD128, DSD256
• S/PDIF (RCA coaxial): 16-24 bit, up to 192 kHz PCM; DSD64 (DoP); 0.5 Vpp on 75 ohm
• AES/EBU (XLR balanced): 16-24 bit, up to 192 kHz PCM; DSD64 (DoP); 2 Vpp on 110 ohm
• Toslink: 16-24 bit, up to 96 kHz (higher with suitable transmitters); DSD64 DoP with high-efficiency transmitters
• Bluetooth: BT 3.0, A2DP, 44.1 / 48 kHz, 16-bit

Technical Specifications

Frequently Asked Questions

What is the Unison Research Unico CD Due?

The Unison Research Unico CD Due is a flagship CD player and DAC from Treviso, Italy, using an ESS Sabre ES9018K2M DAC, four ECC83 tubes in a Class A output stage, and digital inputs covering USB (32-bit/384 kHz/DSD256), S/PDIF, AES/EBU, Toslink, and Bluetooth. It provides both RCA and XLR analog outputs and achieves 125 dB SNR and 0.0003% THD+N.

How does the Unico CD Due compare to the Unico CD Uno?

The Unico CD Due is the flagship model with four ECC83 tubes in its output stage, AES/EBU and S/PDIF digital inputs in addition to USB and Toslink, and both RCA and XLR analog outputs. The CD Uno uses a single ECC82 tube with a solid-state Class A buffer option, only USB and Toslink digital inputs (no AES/EBU or S/PDIF), and only RCA analog output. The CD Uno's IV converter uses NE5532AD rather than the CD Due's AD8597/AD8599. The CD Due is the more comprehensively equipped and more tube-intensive of the two.

Can the Unico CD Due play DSD files from a computer?

Yes. The Unico CD Due's USB input accepts DSD64, DSD128, and DSD256 via asynchronous USB 2.0 Audio Class. Compatible playback software includes Roon, Audirvana, foobar2000 with SACD plugin, and HQPlayer. The S/PDIF and AES/EBU inputs also accept DSD64 via DoP (DSD over PCM). The Toslink input supports DSD64 DoP with high-efficiency optical transmitters.

What is the optional solid-state buffer in the Unico CD Due?

The AD8597/AD8599 solid-state output buffer can be engaged by remote control to bypass the four-ECC83 tube output stage. In bypassed mode, the analog output is driven directly from the AD8597/AD8599 op-amp stage following the IV converter, providing a very low output impedance and a somewhat different sonic character -- typically described as more neutral and precise than the tube stage. The tube stage is the default and is bypassed only when the listener prefers the solid-state output character for specific sources or loudspeaker combinations.

Where can I buy the Unison Research Unico CD Due in Buffalo, NY or the USA?

The Unison Research Unico CD Due is available at Vinyl Sound in Buffalo, NY, USA. Vinyl Sound is an authorized Unison Research dealer serving customers across western New York and the United States. Contact the Vinyl Sound team for current availability and to schedule an in-store demonstration.