TEAC UD-701N USB DAC/Network Player

With a newly-developed original discrete DAC, the UD-701N serves as the core of an advanced audio system, fascinating every audiophile.

Featuring USB DAC functions as its foundation, this unit combines a network player, an analog preamp, a headphone amplifier, and various other functions at a high level. The flagship UD-701N, equipped with a newly-developed TEAC ΔΣ (Delta Sigma) discrete DAC, has achieved a new level of audio quality.

As a USB DAC and network player, it supports 22.5MHz DSD and 384kHz/32-bit PCM. Utilizing the newly-developed TEAC ΔΣ discrete DAC, all digital signals are converted to analog signals with exceptional audio quality.

The UD-701N is versatile and adaptable, suitable for various digital playback scenarios, from systems centered on a PC or Mac to audio server systems using NAS and streaming playback. It can also play a core role in systems as a preamp with both analog and digital inputs. This all-around unit supports new listening styles in a modern age, allowing for speaker playback in combination with a power amplifier and balanced headphone output using a 4-pin XLR jack.

Newly-developed TEAC ΔΣ (Delta Sigma) Discrete DAC

Instead of using a generic DAC IC, we incorporated a newly-developed TEAC ΔΣ (Delta Sigma) discrete DAC comprised of discrete circuitry that uses FPGA incorporating our original algorithms. Analog signals are output with high audio quality. DSD signals are transmitted as is, while PCM signals are transmitted after passing through a ΔΣ modulator and conversion to either 1-bit or multi-bit signals; according to the end users choosing. Achieving a wide, clear sound field, possible specifically because of the discrete design, is TEAC reaching the pinnacle of its sound objectives. With the TEAC ΔΣ discrete DAC, playback of 22.5MHz DSD and 384kHz/32-bit PCM is possible.

Dual Mono Structure

We have incorporated an extravagant dual mono structure throughout the unit, from the power circuit with independent left and right toroidal core transformers to the D/A converter section and analog output stage. This dual model structure, which has complete mono circuits for each of the two channels, prevents interference between the left and right channels, enabling the realization of rich musical expression that reproduces the sense of space and dimension.

Fully-Balanced Transmission at Every Stage

The fully balanced transmission of both the left and right analog output signals from after D/A conversion through the final output stage contributes greatly to improving the signal-to-noise ratio and increasing the dynamic range. This conveys signals in a purer state without losing the sense of air that high-resolution audio sources have. *The circuit boards in this photos are under development.

Four High-Capacity Toroidal Core Transformers

In addition to the 2 toroidal core transformers for the independent left and right analog signals, separate toroidal core transformers are also used in both the network module and digital control sections. In particular, stable electricity is supplied to the network module, which requires advanced processing, by strengthening the power supply for the network module section with linear power.

Analog Preamplifier Function with 2 Line Inputs via RCA/XLR and 4 Digital Inputs

Not only as a USB DAC/Network player that employs two sets of coaxial and optical digital inputs, the UD-701N also works as a high-quality analog preamplifier by employing additional analog audio inputs via RCA and XLR connectors that allow users to connect conventional audio sources. Our TEAC-QVCS (Quad Volume Control System) is a variable gain amp volume control with four independent circuits for left, right, positive and negative (L+, L−, R+ and R−). Placing this in the audio signal route makes it as short as possible, preventing the degradation of audio signals caused by drawing them through signal lines. Moreover, since the volume can be adjusted in extremely fine 0.5dB intervals, you can achieve the ideal volume for the audio system or headphones that you are using.

Improved TEAC-HCLD2 Enhanced-Current Output Buffer Circuits

We used TEAC-HCLD2 circuits, which are improved versions of our TEAC-HCLD (TEAC High Current Line Driver) enhanced-current output buffer circuits. These raise the current transmission capabilities that are important in analog output circuits. Each channel has a positive and negative two-circuit structure with diamond buffer amplifiers, which have high current transmission capabilities, used as line drivers. Drive is differential for balanced output and parallel for unbalanced output. By increasing the current supply ability, transmitting the dynamism of audio signals without loss becomes possible.

4-pin XLR Headphone Amplifier that Can Be Switched Between Balanced and Active Ground

A total of four diamond buffers, one in each of the left, right, positive and negative circuits, are used in the dedicated headphone amplifier, enabling the connection of balanced drive headphones. Moreover, even during single-end use, by driving these amps in parallel, they can provide stronger drive than ordinary single-end headphone amplifiers. This enables the potential of many types of headphones, including 600Ω high-impedance headphones, to be realized. Active ground is a drive method, based on the principles of a balance connection, that approaches 0 V by connecting the COLD connector to the ground and driving the ground forcibly using an amplifier circuit. Not only can a more ideal ground be realized than when using an ordinary ground, the impact of humming noise coming from the power can also be suppressed. Moreover, by lowering the noise floor, we can expect silence to be deepened, allowing the breathing of the artists and the texture of sounds to be felt more intimately.

MQA Full Decoder that Also Supports Digital Inputs

MQA (Master Quality Authenticated) is a high-quality audio codec that enables playback at the same quality level as studio masters. The UD-701N has an MQA decoder that controls D/A-converted waveforms with a precision as fine as 5 ms in order to achieve analog waveforms that are true to the original recordings. Playback sound that seems like the original to the human ear can be achieved by greatly reducing the “sound blurring” that occurs easily when sounds start suddenly and at other times when sound pressure differences are extreme. Since a full decoder is included

DAC Section

• DAC: TEAC ΔΣ Discrete DAC × 2
• Upconvert: 2xFs / 4xFs / 8xFs (maximum 384kHz)

Analog Audio Inputs

• Balanced
  • Connectors: XLR × 1 pair
  • Input Impedance: 50kΩ
  • Maximum Input Level: 5Vrms
• Unbalanced
  • Connectors: RCA Pin (gold-plated) × 1 pair
  • Input Impedance: 25kΩ
  • Maximum Input Level: 2.5Vrms

Digital Audio Inputs

• USB
  • Connectors: USB B-type × 1 (USB2.0 compliant)
  • Supported Formats:
    • PCM 16 / 24 / 32bit
    • 44.1k / 48k / 88.2k / 96k / 176.4k / 192k / 352.8k / 384kHz
    • DSD 2.8M / 5.6M / 11.2M / 22.5MHz

Analog Audio Outputs

• Balanced
  • Connectors: XLR (gold-plated pins) × 1 pair
  • Output Impedance: 220Ω
  • Output Level Settings: Selectable from Fixed (0dB), Fixed (+6dB), Variable, or Off
  • Maximum Output Level: 2.0Vrms (1kHz, Full-scale, 10kΩ loaded, Fixed at 0dB)
  • 4.0Vrms (1kHz, Full-scale, 10kΩ loaded, Fixed at +6dB)
  • 12Vrms (1kHz, Full-scale, 10kΩ loaded, Variable)
• Unbalanced
  • Connectors: RCA Pin (gold-plated) × 1 pair
  • Output Impedance: 180Ω
  • Output Level Settings: Selectable from Fixed (0dB), Fixed (+6dB), Variable, or Off
  • Maximum Output Level: 2.0Vrms (1kHz, Full-scale, 10kΩ loaded, Fixed at 0dB)
  • 4.0Vrms (1kHz, Full-scale, 10kΩ laoded, Fixed at +6dB)
  • 6.0Vrms (1kHz, Full-scale, 10kΩ loaded, Variable)

Headphone Outputs

• Balanced
  • Connector: 4-pin XLR × 1
  • Maximum Output Power: Balanced 700mW + 700mW (32Ω loaded)
• Unbalanced
  • Connector: 6.3mm Stereo jack (gold-plate) × 1
  • Maximum Output Power: Unbalanced 500mW + 500mW (32Ω × 1 loaded)
  • Supported Impedance: 16 to 600Ω

Clock Sync Input

• Connector: BNC (gold-plated) × 1
• Input Frequency: 10MHz
• Input Impedance: 50Ω
• Input Level: Rectangle wave Equivalent to TTL, Sine wave 0.5 to 1.0Vrms

External Control

• Trigger Input (12V TRIGGER IN)
  • Connector: 3.5mm Mono mini jack × 1
  • Input Level: 12V, 1mA
• Trigger Output (12V TRIGGER THRU)
  • Connector: 3.5mm Mono mini jack × 1
  • Output Level: 12V
  • Maximum Current Supply: 100mA

Audio Performance

• Frequency Response: 5Hz to 80,000Hz (+1dB/–5dB)
• Total Harmonic Distortion: 0.002%
• S/N Ratio: 108dB (A-Weight, 1kHz)

Power

• AC Power:
  • AC120V, 60Hz
  • AC220 - 240V, 50/60Hz
• Power Consumption: 40W
• Standby Power: 0.4W

Overall Dimensions

• Dimensions: 444 (W) × 111 (H) × 334 (D) mm (including protrusions)
• Weight: 11.8kg
• Operating Temperature: ＋5℃ to ＋35℃
• Operating Humidity Range: 5% to 85% (no condensation)
• Storage Temperature Range: –20℃ to ＋55℃
• Included Accessory: Power cord, Remote control (RC-1330), AAA batteries × 2, Owner's manual, Foot pad x 3