Dual-monaural DAC/headphone amplifier/preamp
Our take on the TEAC UD-503 by Crutchfield's Steve Kindig
Living room sound quality in a versatile unit sized for a desktop
Music sounds so smooth and relaxed playing through TEAC's UD-503 digital-to-analog converter you may forget you're listening to a digital source. This high-performance DAC delivers virtually any digital music file you're likely to encounter with an amazing sense of transparency and space. Get ready to dive deeper into all your favorite music.
The multi-talented UD-503 is actually three components in one. This high-end DAC is also a high-performance headphone amplifier that delivers powerfully precise sound, and can drive a wide array of today's best headphones. Finally, it's a fully functioning stereo preamp with volume control that can connect to your favorite power amp or active speakers to create a simple but killer-sounding system.
Dual-mono design maximizes stereo separation
The heart of any DAC lies in the actual DAC chips, and for the UD-503, TEAC went with dual high-performance DACs from AKM. These same DAC chips are found in several DACs costing $3000 or more. These are stereo DAC chips, and by using two TEAC was able to reduce noise and crosstalk compared to using a single chip. In fact, the UD-503 uses dual-mono circuitry throughout, including beefy twin toroidal power supplies for potent sound and well-defined stereo imaging.
To get the very best sound quality from the UD-503, connect its USB input to your computer. This is an asynchronous USB input, which allows the UD-503's DAC to control the timing clock signal instead of your computer. This reduces timing jitter to the lowest levels possible for smoother, more detailed sound. The USB input also supports playback of the widest variety of music files, including high-res PCM up to 384kHz/32-bit and DSD up 11.2MHz. The TEAC website has the free USB driver download you'll need for computer playback.
The sound when playing digital sources "as is" is very clean and spacious, but the UD-503 also has the ability to upconvert digital signals of 96kHz and less to 2X, 4X, or 8X the original sampling rate, to reduce jitter even further. You can even upconvert PCM sources to DSD, which can help take the edge off of many of those harsh-sounding CDs from the 80s. There's also a handful of filter options for fine-tuning the DAC's sound to match your system and listening preferences.
The ins and outs
The UD-503's flexible inputs and outputs can handle most stereo systems.
The UD-503 has four digital audio inputs: the aforementioned USB, plus optical and coaxial inputs for connecting a CD/DVD player, game console, media streamer or TV. On the front panel there's a combination mini coax/mini optical input for use with portable devices. And if you're still using an analog audio source, no worries — the UD-503 has a stereo RCA input, as well.
When it comes to getting music out of the UD-503, you'll find unbalanced RCA and balanced XLR outputs for connecting a wide range of power amplifiers. And you can see in the photo that the connectors are widely spaced to accommodate high-quality interconnect cables.
For immersive private listening, TEAC included a superbly engineered headphone amplifier. Two full-size headphone jacks on the front panel allow you to drive two sets of headphones simultaneously, or one pair of headphones in balanced mode.
- plays PCM digital audio sources up to 32-bit/384kHz
- plays Direct Stream Digital (DSD) files at 2.8MHz, 5.6MHz, and 11.2MHz resolution natively or via DoP (DSD over PCM)
- dual AKM VERITA AK4490 32-bit/384kHz digital-to-analog converters for precise playback of digital music files
- dual-monaural design to eliminate interference between right and left channels
- two high-capacity toroidal core power transformers one each for the left and right channels
- built-in high-performance fully-balanced drive headphone amplifier with front-panel volume control
- preamp mode with balanced XLR and unbalanced RCA outputs for connection to an outboard power amp or self-amplified speakers
- asynchronous USB technology for reduced timing jitter and better sound on USB input
- user-defeatable upconversion for digital signals of 96kHz or lower (options include 2X, 4X, 8X and DSD)
- front-panel display shows input signal type and various settings (includes dimmer and off functions)
- compact all-metal chassis and aluminum panels minimize vibration for clean playback
- remote control
- USB (Type B) input for connection to a computer
- Toslink optical digital audio input
- coaxial digital audio input
- front-panel combination mini coax/mini optical audio input for use with portable devices
- analog RCA line-level input
- support for 10MHz external master clock input via BNC coaxial connector
- balanced stereo XLR audio output
- unbalanced stereo RCA audio output
- two full-size 1/4" headphone jacks (compatible with headphones with 16-600 ohms impedance)
- headphone amplifier can be switched among 3 drive types: unbalanced, balanced, or active ground
Other Info & Specs:
- Type B USB input supports up to 32-bit/384kHz resolution for PCM; up to 11.2MHz for DSD
- coaxial input supports up to 24-bit/192kHz resolution for PCM; up to 2.8MHz for DSD
- Toslink optical input supports up to 24-bit/192kHz resolution for PCM; up to 2.8MHz for DSD
- compatible with Windows® and Mac®
- TEAC HR Audio Player app required for high-resolution audio playback on Windows and Mac computers (free USB driver download available from TEAC's website)
- frequency response: 5-80,000 Hz (+1 dB/-3 dB)
- THD: 0.0015%
- signal-to-noise ratio: 112 dB balanced; 110 dB unbalanced
- detachable AC power cable
- 11-7/16"W x 3-5/16"H x 11-1/4"D
- weight: 9.3 lbs.
- If connecting to a TV, please make sure you can select "PCM" output in your TV's audio menu. This DAC cannot decode multi-channel Dolby® Digital signals.
- warranty: 1 year
- Our 60-day money-back guarantee
What's in the Box:
- USB DAC/headphone amp
- 6.5' AC power cord
- Remote control (RC-1319)
- 2 "AAA" batteries
- 4.5" RCA-to-minijack cable
- 3 Self-adhesive pads
- Owner's Manual
- "Caution" sheet
Scratch & Dent items may be missing non-essential accessories. In some cases the manufacturer's accessories have been replaced with generic equivalents.
This TEAC unit can handle every currently available digital file format (quad DSD and DXD included!) with a grace and precision that belies its price point. I am continually amazed by - and pleased with - its clarity and naturalness of sound reproduction.
Jeffrey H., Winston-Salem, NC
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Dual-Monaural Structure: The TEAC UD-503 employs a dual-monaural circuit structure that encompasses every aspect from the power and D/A sections to the analog output stage. Starting with the toroidal core power transformers, which feature the ability to supply stable current, and the high-performance VERITA AK4490 DACs, the dual-monaural structure has a complete mono circuit for each channel. This prevents the signals from interfering with each other as much as possible. Interference is suppressed between the left and right channels, which is particularly important for headphone listening, so this unit can also be used as a high-performance headphone amplifier.
Independent High-Capacity Toroidal Core Power Transformer: Both left and right channels each have one dedicated high-capacity toroidal core power transformer that supplies stable current. This is also a continuation of the dual-monaural design and enables the stable supply of current to each channel without being influenced by the changes in current consumption due to processing of the other channel's signal.
Isolation Circuitry: Between the digital and analog sections, the circuit design uses a digital isolator to completely isolate both the power supply and the ground. So, all noise coming from digital input sources, starting with noise from the computer via USB, is prevented from entering the analog section by way of the power line or the ground. An isolation circuit offers significant benefit particularly when playing high-resolution audio sources with high sampling rates.
High-performance VERITA AK4490 DACs: The TEAC UD-503 utilizes VERITA AK4490 DACs, which are made by AKM (Asahi Kasei Microdevices) Corporation and have an established reputation for use in high-end audio equipment. The VERITA AK4490 DACs provide the fine expressive capability suitable for the playback of high-resolution audio sources that reproduce sound waves outside the human audible range. The high-resolution audio DACs support up to DSD 11.2MHz native playback, as well as PCM 385kHz/32-bit playback.
TEAC-HCLD Output Buffer Circuit: In order to transfer music signals to output devices without losing their dynamic range, the UD-503 utilizes TEAC-HCLD (High Current Line Driver) circuits. These circuits increase the current transfer capability that is crucial for analog outputs. Each channel side includes two buffer circuits with high current transfer capabilities. By using differential drive for balanced output and parallel drive for unbalanced output, current transfer capabilities are increased, allowing the transfer of music signals without losing their dynamics.
PCM UpConversion: In addition to DSD 11.2MHz native playback and PCM 384kHz/32-bit Hi-Res playback, the TEAC UD-503 will upconvert your lower resolution PCM music files bringing new life to your digital music collection. You can use the upconversion function with the USB-B, Optical, or Coaxial digital inputs.
- 2Fs: If the input audio signal is less than 2x a standard sampling frequency (32/44.1/48kHz), it is upconverted 2x and then sent to the D/A converter.
- 4Fs: If the input audio signal is less than 4x a standard sampling frequency (32/44.1/48kHz), it is upconverted 4x and then sent to the D/A converter.
- 8Fs: If the input audio signal is less than 8x a standard sampling frequency (32/44.1/48kHz), it is upconverted 8x and then sent to the D/A converter.
- DSD: The input source is converted to DSD digital format and then sent to the D/A converter.
- Off: The original input signal is sent directly to the D/A converter without conversion.
Upconversion Table: The relationship between input sampling frequencies and sampling frequencies after upconversion are as follows.
|Input Source||Upconversion Setting|
|Input Sampling Frequency (PCM)||Sampling Frequency After Conversion|
|32 kHz||N/A||32 kHz||64 kHz||128 kHz||256 kHz||8.0 MHz|
|44.1 kHz||44.1 kHz||44.1 kHz||88.2 kHz||176.4 kHz||352.8 kHz||11.2 MHz|
|88.2 kHz||88.2 kHz||88.2 kHz||88.2 kHz||176.4 kHz||352.8 kHz||11.2 MHz|
|176.4 kHz||176.4 kHz||176.4 kHz||176.4 kHz||176.4 kHz||352.8 kHz||11.2 MHz|
|N/A||352.8 kHz||352.8 kHz||352.8 kHz||352.8 kHz||352.8 kHz||11.2 MHz|
|48 kHz||48 kHz||48 kHz||96 kHz||192 kHz||384 kHz||12.2 MHz|
|96 kHz||96 kHz||96 kHz||96 kHz||192 kHz||384 kHz||12.2 MHz|
|192 kHz||192 kHz||192 kHz||192 kHz||192 kHz||384 kHz||12.2 MHz|
|N/A||384 kHz||384 kHz||384 kHz||384 kHz||384 kHz||12.2 MHz|
Full-Metal Body: The TEAC UD-503's full-metal chassis is wrapped from both sides with 8mm-thick aluminum panels, while a center beam connects the front and rear of the chassis. These features prevent twisting and bending to produce a strong and stable body. The UD-503's full-metal body construction is effective against external noise and suppresses the penetration of electromagnetic noise emitted by computers and other devices. This helps to produce a clean internal environment with low noise even when the surroundings are hostile to audio equipment.
3 Supportive Pinpoint Feet: The three-point support method used for the legs enables stable body installation without influence from even the slightest surface irregularities. Each pinpoint foot used on the UD-503 is composed of the foot itself that is attached firmly to the chassis, and a foot base. The base flange (the outer rim of the mortar-shaped part) hangs from the flanges of three screws. Due to this structure, the interlocking flanges prevent the feet bases from falling off or shifting when the body of the unit is lifted. When the unit is placed, each spike point touches only the single deepest point in the mortar-shaped part of its base. Vibrations and resonance are reduced by supporting the body of the unit on these pinpoints. This thoroughly eliminates mid and low frequency heaviness and murkiness and delivers improved resolution, which brings out the details of sounds and sound placement.
Note: Apply the included pads to the bottoms of the foot-stands to avoid scratching the surface where the unit is placed.
Asynchronous USB-B 2.0: The TEAC UD-503 is equipped with a rear-panel USB-B 2.0 input for connection to your computer and playback of your computer's music library. When connected by USB, rather than synchronizing with a computer clock that is unstable and noisy, the UD-503 supports asynchronous USB transfer mode; allowing it to control PCM and DSD signals by synchronizing with its own clock generated by its built-in high-precision crystal oscillator. Two dedicated internal clocks running at 44.1kHz and 48kHz are built in. You'll be able to playback DSD and PCM music files stored on your computer.
- Compatible Operating Systems:
- Windows: 7 (32/64-bit), 8 (32/64-bit), 8.1 (32/64-bit), or 10 (32/64-bit); Windows will require a dedicated USB driver download.
- Mac OS X: Lion (10.7), Mountain Lion (10.8), Mavericks (10.9), or Yosemite (10.10)
- Compatible Music Files:
- DSD: 2.8, 5.6, 11.2 MHz
- PCM: 44.1, 48, 88.2, 96, 176.5, 192, 352.8, 384 kHz
HR Audio Player App (for Windows & Mac): The free TEAC HR Audio Player application software lets you get more out of the TEAC UD-503's USB input by supporting a variety of other music files, in addition to DSD and PCM, on your Windows or Mac computer. Simply download this free application software onto your compatible Windows PC or Mac computer.
- Compatible Operating Systems:
- Windows: 7 (32/64-bit), 8 (32/64-bit), 8.1 (32/64-bit), or 10 (32/64-bit); Windows will require a dedicated.
- Mac OS X: Lion (10.7), Mountain Lion (10.8), Mavericks (10.9), or Yosemite (10.10)
- Compatible Music Files:
- DSD/DSDIFF: 2.8, 5.6, 11.2 MHz
- PCM/WAV: 44.1 to 384 kHz; 16 to 32-bit
- AIFF/ALAC: 44.1 to 384 kHz; 16 to 32-bit
- FLAC: 44.1 to 384kHz; 16 to 32-bit
- MP3: 32 to 320 kbps
Master Clock Input: With support for 10MHz external master clock input (via a BNC coaxial connector), synchronization with master clock signals of even higher precision is possible. By synchronizing with clock that has an even higher precision, you can enjoy changes in tone quality and improved audio quality.
Digital & Analog Inputs: The TEAC UD-503 features two rear-panel digital inputs, an Optical (Toslink) input and a Coaxial (RCA) input, plus a front-panel Optical/Coaxial-Mini combined input (a coaxial-to-minijack conversion cable is included). The rear-panel digital inputs support up to a 24-bit/192kHz PCM audio signal, as well as 2.8MHz DSD (DoP) audio. The front-panel digital input makes it simple to connect a portable digital audio player capable of a digital output. TEAC has even considered connection of record players such as the TEAC TN-300 or TN-400S turntable (sold separately), cassette decks and other analog sources with line outputs by also including one pair of analog RCA inputs.
Note: This UD-503 does not support Dolby Digital, DTS or AAC through its digital inputs.
Balanced & Unbalanced Preamp Outputs: One pair of XLR balanced outputs and one pair of RCA unbalanced outputs are included and can be set to either a variable or a fixed volume level, allowing a simple system to be put together in combination with a power amplifier or active speakers. The XLR balanced and RCA unbalanced outputs have been symmetrically located for the shortest signal paths. There are four line output level settings.
- Fix 0dB: A maximum of 2Vrms is output. Select this if you want to adjust the volume using an external amplifier. Not sound will be output if headphones are connected.
- Fix +6dB: A maximum of 4Vrms is output. Select this if you want to adjust the volume using an external amplifier. No sound will be output if headphones are connected. If the sound distorts, set to Fix 0dB instead.
- Variable: This will enable adjustment of the analog output level using the UD-503's volume knob. Select this if you want to adjust the volume using the UD-503's volume knob. No sound will be output if headphones are connected.
- Off: No sound is ever output from the analog preamp line-level analog outputs.
Discrete, Full-Balanced Headphone Amplifier: The TEAC UD-503 is equipped with a discrete, fully balanced headphone amplifier. On the front of the unit, two 3-pole TRS (standard stereo) jacks are provided as headphone outputs. These outputs can be switched between three types of drive operations. In addition to connecting balanced drive headphones, you can also use unbalanced drive to connect two pairs of ordinary headphones, as well as use active ground drive, which can further decrease noise during silences and enhance the expressiveness of delicate sounds.
- Balanced Drive: The connection of balanced drive headphones is enabled by utilizing TEAC's HCLD circuits, which are composed of 4 output transistors on each of the left and right channels. You can connect one set of unbalanced headphones using the UD-503's the left and right headphone output jacks.
- Unbalanced Drive: The TEAC HCLD circuits and transistors operate in parallel during connection of unbalanced headphones. You can connect one set of headphones to either the left or right headphone jack, or connect two sets of headphones using both headphone outputs. When connecting two pair of headphones, use headphones with the same impedance and efficiency since they will be sharing the same volume control.
- Active Ground Drive: The active ground method is a drive method that, using the same connection method as balanced connection, forcibly sets the COLD to stable 0V with an amplifier circuit that connects the COLD to the ground. This method effectively suppresses the influence of hum from the power supply, lowering the noise floor. One set of balanced headphones can be connected.
TEAC-QVCS (Quad Volume Control System): For the preamp circuit, the UD-503 utilizes the TEAC-QVCS (Quad Volume Control System), which is a circuit with a fully-balanced design that uses balanced processing of the audio signal at every stage from immediately after conversion from digital to analog until it reaches the volume amplifier.
- 4 Circuit Structure: Control signals transmitted from the volume knob simultaneously adjust the variable gain amp type volume controls for a total of four independent circuits-positive and negative for both of the left and right channels. Using this system, the unnecessary manipulation of audio signals is eliminated, and the left/right and positive/negative independence of the audio signals is preserved, achieving clear sound quality with outstanding channel separation (this does not apply when using unbalanced analog inputs).
- 256 Steps/0.5dB Increments: This volume control system offers 256 steps of volume adjustment in 0.5dB increments over the complete range from −95 dB to +24 dB. Precise volume adjustment has even been made possible using a remote control. In addition, optimal volume levels can be achieved for headphone listening using headphones with various levels of efficiency.
Digital Filters: In addition to four types of PCM digital filters and an OFF mode, the unit has two types of DSD digital filters, so you can choose the best filter for the input file format and type of music. You can enjoy the subtle sound nuances of different filters without needing to connect different USB DACs.
- PCM Filters:
- FIR Sharp: a FIR filter with a steep roll-off sharply cuts signals outside the audio band
- FIR Slow: a FIR filter with a low roll-off gently cuts signals outside the audio band
- SDLY Sharp: a short delay filter with a steep roll-off sharply cuts signals outside the audio band
- SDLY Slow: a short delay filter with a slow roll-off gently cuts signals outside the audio band
- DSD Filters:
- 50kHz: use to set a 50kHz cutoff frequency when receiving a DSD audio signal
- 150kHz: use to set a 150kHz cutoff frequency when receiving a DSD audio signal
Note: When receiving signals at 352.8kHz or 384 Hz, the digital filter will be disabled during playback regardless of this setting.
IR Remote: The TEAC UD-503 comes with an IR remote control for wireless operation of the USB DAC/Preamp/Headphone Amplifier. Remote control functions include Power on/off, Input selections, Volume up/down, Mute, OLED dimmer, Upconversion mode, Filter mode, Headphone type, and Menu selection.
Organic Electroluminescent Display (OLED): The organic electroluminescent display (OLED) with a 4-level dimmer provides high contrast and excellent visibility. A large font is used to enable listeners to check the source input and volume level even from a distant.
Automatic Power Saving Function: The unit will automatically enter Standby mode if there is no audio input for approximately 30 minutes.
Our Product Research Team
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Why did you buy this?
Supports USB input from computer, balanced headphone jacks on the front panel, wide range of resolutions it supports. Will have to hear it for the final will I keep it or not. For the price it seems like a very good deal. [ KERRY L Jul 17, 2018 ]
After hours of research, I determined that this would be the best DAC I could obtain for my listening habits. [ MUHAMMAD May 25, 2017 ]