USB DAC / Preamplifier / Headphone Amplifier

UD-507

Completely redesigned 500 Series DAC/Preamp/Headphone amplifier with high-end 700 Series design concept in a compact A4-size package.

The UD-507 is equipped with our proprietary “TRDD 5” discrete DAC, designed with musicality as the top priority.
Following in the footsteps of TEAC's acclaimed 701 series, the new “TRDD 5” discrete DAC offers a clear soundstage and accurate imaging, providing listeners with a truly immersive musical experience.

Fully Balanced
Dual Monaural Headphone Amplifier

The UD-507 is a headphone amplifier featuring the TEAC-HCLD2 high current line driver, which is characterized by its high current supply capability.
Compared to the previous model, the maximum output power has been greatly improved by strengthening the power supply, resulting in a generous driving power of 1,200mW + 1,200mW (balanced output at 100 ohm load), which is comparable to a dedicated headphone amplifier without DAC.
The power amplifier gain can be switched between 3 positions (Low/Mid/High) to fine-tune the output to best match the sensitivity and impedance of the headphones.

High-Quality Preamplifier
with Multiple Analog/Digital Inputs

The UD-507 incorporates the TEAC-QVCS high precision analog volume attenuator and the powerful TEAC-HCLD2 high current line buffer circuit.
With five digital inputs and two analog inputs (unbalanced and balanced), a wide variety of devices can be connected.

Proprietary “TEAC Reference Discrete DAC: TRDD 5”

All digital signals input to the UD-507 are processed at 64bit/512Fs by the delta-sigma modulator in the FPGA, which incorporates a proprietary algorithm, and converted to analog signals by 16 elements per channel (one element is a pair of logic circuits and a low-pass filter with high-precision resistors). The DSD signal is processed directly, while the PCM signal is converted to a 1-bit signal by a delta-sigma modulator before being output as a high-quality analog signal. 22.5MHz DSD and 384kHz/32bit PCM playback is possible. Two operating methods can be selected according to your preference: the multilevel (multi-bit) delta-sigma method or the 1-bit delta-sigma method.

In Addition to 44.1kHz and 48kHz Internal Clocks, 10MHz External Clock Input Is Supported

For USB audio playback, the UD-507 supports the USB Asynchronous Transfer Method, which controls PCM and DSD data transfer by synchronizing to the clock generated by the UD-507’s internal high-precision crystal oscillator, instead of synchronizing to the unstable and noisy PC clock. The internal clock is equipped with two types of dedicated clocks, 44.1kHz and 48kHz series, each of which applies an audio-grade high-precision crystal oscillator with low phase noise to input signals at integer multiples, greatly minimizing the effect of jitter on sound quality and faithfully reproducing the original sound. The UD-507 also supports a 10MHz external clock input that can be synchronized to an external master clock signal. Synchronization with a high-precision external clock enables an upgrade to even higher quality music reproduction.

Dual Monaural Construction

The D/A converter section is independent of the left and right channels, and a luxurious dual monaural circuit is used throughout the analog output stage. The dual monaural configuration, with two monaural circuits for each channel, prevents interference between L/R signals and reproduces music with a spacious and three-dimensional soundstage.

Fully Balanced Signal Transfer

Fully balanced transmission of the L/R analog output signals from the D/A conversion stage to the final output stage greatly improves signal-to-noise ratio and expands the dynamic range, enabling pure reproduction of the spatial information contained in high-resolution sound sources.

Two Large Toroidal Core Transformers / Non-feedback Power Supply Circuit

The UD-507 is equipped with one toroidal transformer each for the analog (including the analog section of the DAC) and digital processing boards. By separating the analog and digital power supply sections, mutual interference is avoided and the purity of the analog signal is improved. In addition, a no-feedback circuit is used for the analog power supply circuit to provide more musical reproduction capability.

Preamplifier with Analog Volume Control – 4 Digital Inputs and 2 Line Inputs (RCA/XLR)

The UD-507 has two digital inputs each for coaxial and optical digital, as well as RCA and XLR analog inputs, allowing it to be used not only as a USB DAC, but also as a high-quality analog preamplifier.
The TEAC-QVCS (Quad Volume Control System), which uses a variable gain controller with four independent circuits for left, right, positive, and negative (L+, L–, R+, R–), is placed on the audio signal path to minimize the signal path and prevent audio signal degradation due to signal line routing. The TEAC-QVCS also provides fine volume control in 0.5dB increments, allowing you to set the volume level that best suits your audio system and headphones.

Improved TEAC-HCLD2 Enhanced-Current Output Buffer Circuits

The UD-507 is implemented with TEAC-HCLD2 output buffer circuits, which are enhanced versions of our TEAC-HCLD (TEAC High Current Line Driver) circuits. These increase the current transfer capabilities that are important in analog output circuits. Each channel has a positive and negative dual circuit structure with high current transfer diamond buffer amplifiers used as line drivers. The drive is differential for balanced output and parallel for unbalanced output. By increasing the current handling capability, it is possible to transmit the dynamics of audio signals without loss.

Headphone Amplifier with 4-Pin XLR and Pentaconn Jack with Switchable Balanced/Active Ground

The UD-507 is equipped with a dedicated headphone amplifier that uses four diamond buffer circuits, one positive and one negative circuit on each channel, to allow the connection of balanced headphones. The amplifier can bring out the potential of various types of headphones, including high-impedance headphones of 600 ohms. The active ground method uses the principle of a balanced circuit configuration to electrically drive the cold side to 0V by means of an amplifier circuit. Since the ground potential is always fixed at 0V, this method is not only more ideal than the usual method of grounding the cold side, but also has the effect of suppressing the effects of hum from the power supply, and the lower noise floor makes the system quieter, allowing the listener to feel the artist's breath and sound textures more closely.

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-507 has an MQA decoder that controls D/A-converted waveforms with a precision as fine as 5ms 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-507.

Up-Sampling Function

The up-sampling 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 20kHz 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 20kHz.

Bluetooth Receiver Supporting LDAC, Aptx™ HD High-Quality Audio Communication and Multipoint Connection

The UD-507 supports LDAC™ and LHDC codecs, which are capable of transmitting high-resolution audio data (96kHz/24bit), as well as Qualcomm^® aptX™ HD, which is capable of transmitting at 48kHz/24bit. The UD-507 also supports versatile codecs such as AAC, Qualcomm^® aptX™ and SBC, enabling casual enjoyment of high-quality wireless playback from smartphones and DAPs (digital audio players). It also supports multi-point connectivity, allowing two devices to be wirelessly connected at the same time and seamlessly switch between them for listening.

Bulk Pet USB Transfer Technology Enables Stable Data Transmission

When transmitting large amounts of digital data by USB cable from high-resolution audio sources, large inconsistencies arise in the processing loads of both the sending computer and the receiving USB DAC, and audio dropouts and other problems can occur. Using the Bulk Pet USB transfer technology, however, the same amount of data is transmitted at a steady rate, leveling the processing loads of both sides and realizing stable data transmission. Since changes in computer load conditions can also affect audio quality, you can select from four preset transmission modes to choose the preferred audio quality.

Spec description
Supported formats     
USB input     
PCM    16/24/32 bit
44.1k/48k/88.2k/96k/176.4k/192k/352.8k/384k Hz
DSD    2.8M/5.6M/11.2M/22.5M Hz
Coaxial digital input     
PCM    16/24 bit
32k/44.1k/48k/88.2k/96k/176.4k/192k Hz
DSD    2.8MHz (supported with 176.4kHz/24-bit DoP format)
Optical digital input     
PCM    16/24 bit
32k/44.1k/48k/88.2k/96k/176.4k/192k Hz
DSD    2.8MHz (supported with 176.4kHz/24-bit DoP format)
DAC section     
USB DAC    In-house designed Discrete DAC TRDD5
Up-conversion    up to 384kHz/32-bit PCM
Audio inputs     
USB    USB Type-C port × 1
USB Type-B port × 1
USB version    2.0
Transfer Mode    Asynchronous mode transfer, Bulk Pet
Compatible Software    TEAC HR Audio Player (Windows, Macintosh)
COAXIAL digital (rear)    RCA pin ×1 (gold-plated)
Input level    0.5Vp-p
Input impedance    75Ω
Optical digital (rear)    TOS-link ×1
Input level    -24.0 to -14.5dBm peak
Analog (Balanced)    XLR ×1 pair (gold-plated)
Input impedance    50kΩ
Input sensitivity    5Vrms
Analog (Unbalanced)    RCA pin ×1 pair (gold-plated)
Input impedance    24kΩ
Input sensitivity    2.5Vrms
Bluetooth®     
Bluetooth® version    4.2
Output class    Class2 (Range: approx. 33ft/10m)
Supported profiles    A2DP, AVRCP
Content protection    SCMS-T
Supported codec    LDAC™, LHDC, Qualcomm® aptX™ HD, aptX™, AAC, SBC
No. of paired device    maximum 8 devices
No. of multipoint connection device    maximum 2 devices
Audio outputs     
XLR balanced    XLR ×1 pair (gold-plated)
Maximum output level    1kHz, full scale, into 10kΩ
 0dB setting    2.0Vrms
+6dB setting    4.0Vrms
Output impedance    40Ω
RCA unbalanced    RCA pin ×1 pair (gold-plated)
Maximum output leve    1kHz, full scale, into 10kΩ
 0dB setting    2.0Vrms
Output impedance    20Ω
Headphone outputs     
Connector 1    1/4” (6.3mm) TRS stereo jacks × 1 (gold-plated)
Connector 2    XLR 4pin jack ×1 (gold-plated)
Connector 3    4.4mm 5-pole Pentaconn jack ×1 (gold-plated)
Maximum output     
Balanced    1200mW + 1200mW (into 100Ω)
Active Ground    900mW + 900mW (into 32Ω)
Unbalanced    900mW + 900mW (into 32Ω)
Supported impedances    16 to 600Ω
Clock section     
External clock input     
Connector    BNC (gold-plated)
Input frequency    10MHz
Input impedance    50Ω
Input level    Rectangle wave: equivalent to TTL levels
Sine wave: 0.5 to 1.0 Vrms
External control     
12V Trigger out     
Conenctor    3.5mm Monaural Mini jack × 1
Output level    12V
Max. current supply    100mA
Audio performance    192kHz/24bit PCM input, RCA output, DAC mode MULTIBIT
Frequency Response    5Hz to 70kHz (+1/–6 dB)
Total harmonic distortion    0.01% or less (1kHz, LPF: 20Hz to 20kHz)
S/N ratio    105dB or higher (A-weight, 1kHz)
Power supply     
US/Canada    AC 120V 60Hz
UK/Europe    AC 220 to 240V 50Hz
Power consumption    18W (0.4W in standby)
dimensions (including protrusions)    290(W)×85(H)×249 (D) mm / 11.4”(W)×3.3”(H)×9.8”(D)
Weight    4.9kg / 10.8lbs
Included accessories    Power cord, Remote control (RC-1334), AAA Batteries for remote control × 2, feet cushions × 3, Owner's Manual (with warranty)