NT-503

The key to a great-sounding digital audio system is the DAC. The NT-503 employs a pair of VERITA AK4490 DACs, designed by Asahi Kasei Microdevices Corporation.

The VELVET SOUND architecture on the AK4490 is capable of produce fine-detailed expression of sound even outside the human audible range to make Hi-Res Audio playback sound its best. Its newly developed Low Distortion Technology boats 112dB of S/(N+D), the highest level in the industry for a 120dB-class DAC.

In addition to 11.2MHz DSD Native playback, the NT-503 also supports a wide variety of Hi-Res Audio sources, including 32-bit/384kHz PCM. Smooth details and outstanding sense of sound placement are reproduced at the limits of Hi-Res Audio.

The NT-503 includes TEAC’s latest FPGA (programmable IC) with our exclusive Fluency up-conversion algorithm. In addition to the 2x, 4x, and 8x PCM up-conversion processing, DSD up-conversion is also supported as high as 12.2MHz (4x DSD). Thanks to this unique system, the NT-503 up-converts 16-bit/44.1kHz data from a conventional CD into 11.2MHz DSD – over 256 times the data. Audio data higher than 20kHz is produced by an analogical interpolation algorithm to restore natural sound as close as the original one. You will experience the dense sense of air that the DSD format inherently has, even when listening to CD or MP3 from your huge music collection.

The NT-503 hosts a pair of sample clocks, one each for multiples of 44.1kHz and 48kHz. In addition, a 10MHz clock input allows the DAC to be connected to Rubidium or GPS clocks for calibration or constant use.

In addition to four types of PCM digital filters and an OFF mode, the unit has two types of DSD digital filters. 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.

• FIR SHARP：An FIR filter with a steep roll-off sharply cuts signals outside the audio band.*
• FIR SLOW：An FIR filter with a slow 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.*

• CUTOFF：  50kHz  150kHz

Behind the best-in-class performance of the NT-503 is an all-new, lavish dual-monaural circuit design. From the power supply through the DAC units and analog output stage, the circuitry is a mirrored pair of perfectly matched components. A pair of high-efficiency Toroidal-core power transformers and high-performance VERITA AK4490 DAC chips, for example, are installed on each channel as a single monaural circuit, preventing one audio signal from interfering the other.

Based on TEAC’s decades of experience in high-end audio design, the analog amplifier section employs a pair of discrete enhanced-current buffer amplifiers. The “TEAC-HCLD” (High Current Line Driver) circuits on each channel enhances transient character by processing a differential drive in balanced output mode and parallel drive in unbalanced output mode. As results, the NT-503 delivers the wide dynamic range the original Hi-Res Audio data without losing dynamism of music.

Between the digital and analog sections, the NT-503 employs a Digital Isolator to completely isolate each power supply path and the ground. All digital noise from digital sources, particularly a PC plugged into the USB input, is prevented from entering the analog section through a power supply path or the ground. An isolation circuit offers significant benefit particularly when playing back Hi-Res Audio sources that have higher sampling frequency.

The NT-503 accommodates a high-capacity Toroidal-core power transformer on both left and right channels, to supply clean and stable current independently on the dual-monaural design concept. Each power unit ensures a stable current supply to each channel without being influenced by changes in current consumption from the other channel's signal. The dual power supply deign normally reserved for large, high-end components is applied here for peak performance.

The organic electroluminescent display (OELD) with a 4-level dimmer provides high contrast and excellent visibility. A large-sized font allows you to check the volume level even from across the room.

With a single USB Cable, Hi-Res Audio data including 11.2MHz DSD and 32-bit/384kHz PCM can be played back without complex settings. TEAC offers a free music app, "TEAC HR Audio Player,” for Windows and Macintosh systems. It allows listeners to create, save, and recall their own playlists, or simply just drag-and-drop music files to the playlist window.

The NT-503 is a versatile network player that offers network audio capability with DLNA 1.5. Hi-Res Audio formats such as 5.6MHz DSD and 24-bit/192kHz WAV/FLAC can be played back from a PC or NAS (Network Attached Server.) Playback can be controlled with a free app for iOS or Android, "TEAC HR Remote".

Gapless playback is also supported when playing back files of the same sampling frequency, even if the file format varies between WAV, FLAC, AAC, Apple Lossless, WMA, OGG Vorbis, and MP3.
* Gappless playback does not support tracks of less than 30 seconds duration.

The NT-503 supports Bluetooth® wireless connection using advanced codec technologies like Qualcomm® aptX™, AAC, and SBC for the best audio performance possible. Enjoy high-quality music streaming from your smartphone or tablet.

The NT-503's USB port on front panel supports 5.6MHz DSD and 192kHz PCM stored on a USB Flash Memory, as well as conventional MP3 and WMA files. The free app "TEAC HR Remote" for iOS/Android turns your smartphone and tablet into a touch-screen remote controller to browse and select music files on the USB Flash Memory. Gapless playback is also supported when playing back the same sampling frequency files between, WAV, FLAC, AAC, Apple Lossless, WMA, OGG Vorbis, and MP3.
* Gappless playback does not support tracks of less than 30 seconds duration.

The free apps "TEAC HR Remote" for iOS and "TEAC AVR Remote" for Android allows the NT-503 to subscribe on-line music services like Pandora*, Sirius/XM*, Spotify*, Deezer*, and Slacker*. In addition, access the Internet radio portal* that provides over 100,000 radio stations and 4 million podcasts all over the world for free. Since the NT-503 directly receives those streaming signal from Internet, – not via your smartphone or tablet – your ringtone will not interrupt the music.

The NT-503's high-quality analog output circuit, based around its dual-monaural design and the “TEAC-HCLD” circuit, creates the ideal pre-amplifier unit. The NT-503 delivers both balanced and unbalanced audio signals, either at at "Fixed (±0dB)", "Fixed (+6dB)" (optimized for DSD sources), or "Variable" to connect to a power amplifier. In addition to these settings, the "Off" setting disables audio signals to the rear connectors, consentrating its performance on the headphone output.

In the pre-amp section, the NT-503 employs the “TEAC-QVCS” (Quad Volume Control System), a fully-balanced circuit design from the output of the D/A Converters and Volume Amplifier section. Control signals from the volume knob precisely control four independent variable-gain amplifiers simultaneously — both positive and negative for the left and right channels. With this circuit design, audio signal paths are simplified and independant left and right channels and phase is preserved for clear sound quality with outstanding channel separation. (This does not apply to unbalanced analog input.)

This "TEAC-QVCS" also provides 256 steps or 0.5dB steps of volume control, precisely throughout the effective range from -95dB to +24dB. Both the line output and headphone volume can be controlled to the exact level you wish with a remote control, something that's difficult to achieve with a motorized volume control. This feature becomes even more useful when connecting various types of headphones with different impedances.

Like the UD-503, the NT-503 also employs a high-performance headphone amplifier that delivers 500mW+500mW of output power. The “TEAC-HCLD” circuits, based around four output transistors in parallel-drive mode, drive conventional single-ended headphones powerfully and precisely. In addition, a uniquely-designed class-AB amplifier with extended class-A operation range allows the NT-503 to process most part of amplification process in class-A mode, and maximizes potential of wide range of headphones, including 600 ohms high-impedance ones.