Dual mono structure
We have incorporated a best-in-class 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 improves the signal-to-noise ratio and the dynamic range. This conveys signals in a purer state without losing the sense of air that high-resolution audio sources have.
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, but 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 a 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.
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 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, in addition to file and network playback, MQA data from digital inputs can also be decoded. Playback of MQA CDs is possible by connecting the digital output of a CD player to the UD-701N.
The up-conversion function uses RDOT-NEO (Refined Digital Output Technology NEO) to smoothly augment PCM digital audio signals and upconvert their sampling frequencies 2, 4, or 8 times (384kHz maximum). RDOT, which applies an analogous interpolation method using fluency logic, is a technology that was developed to enable reproduction and playback of frequencies higher than 20 kHz that are lost by 44.1kHz/48kHz digital signals. Based on the information read, analogous data is generated between the waveform samples, which also results in data above.
Bluetooth® receiver supports LDAC, aptX™ HD, and other high-resolution transmission formats
In addition to the LDAC™ and LHDC codecs, which can transmit audio data with quality that is considered high resolution (96kHz/24-bit), it also supports Qualcomm® aptX™ HD, which is capable of 48kHz/24-bit transmission. Of course, the popular AAC, Qualcomm® aptX™, and SBC codecs are also supported, so you can easily enjoy high-quality wireless playback from smartphones and digital audio players.