TEAC AI-503 Product information

Brand

TEAC

Series

Reference 503

Model

AI-503-S

AI-503-B

Color

Silver

Black

Main unit size (W × H × D)/weight

290 × 81.2 × 264 mm/3.7 kg

(11 1/2" × 3 1/4" × 10 1/2" / 8 1/4 lb)

Packaging size/weight

444 × 193 × 345 mm/5.1 kg

(17 1/2” × 7 5/8” × 13 5/8" / 11 1/4 lb)

Product information

AI-503

USB DAC/Integrated Amplifier

Integrated amplifier with Bluetooth function and a dual mono USB DAC (supports
formats up to 11.2MHz DSD) for the high-resolution digital audio player age

■ Main features

 USB DAC with a dual-mono configuration that supports resolutions up to 11.2MHz DSD and

384kHz/32bit PCM

 Bluetooth® receiver supports LDACTM/Qualcomm® aptXTM for high quality wireless audio quality
 Dedicated headphone amp with discrete, push-pull circuit
 Headphone jack supports 3.5mm 4-pole separate ground connection
 Combined stereo mini/optical digital jack on front panel, convenient for connecting digital audio

players

 Pre-amp section provides fully balanced transmission and uses TEAC-QVCS high-precision volume

control circuit

 High-output Class-D power amplifier (made by ICEpower a/s)
 Switchable filter types, including 4 PCM and 2 DSD digital filters
 Pre-out jacks can be connected to both power amplifiers and active speakers
 Two pairs of analog RCA inputs, as well as USB, optical and coaxial digital inputs (one each) on

back panel

 Dual analog level meters with adjustable brightness

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Product information

■ Overview

The AI-503 is an integrated amp and USB DAC that supports inputs up to 11.2MHz DSD and
384kHz/32-bit PCM. The DAC/preamp, which is the heart of the unit, follows the same design concept
of our UD-503 and adopts a dual-mono circuit design that is fully balanced. Separate VERITA AK4490
D/A converters - made by Asahi Kasei Microdevices Corporation - are used for the left and right
channels. In addition to a USB digital input (for Windows/Mac computers), optical/coaxial digital input
and RCA analog input, we have also enabled high-resolution wireless audio listening by including a
LDAC-compatible Bluetooth® receiver. Furthermore, with a combined 3.5mm optical digital/stereo
mini jack on the front panel, the unit supports wired, as well as wireless, input from DAPs.

The power amplifier uses a Class-D power amplifier (made by ICEpower a/s) that guarantees high
resolution during the playback of delicate signals as well as high linearity at high volumes. This unit can
power both compact bookshelf speakers (for desktop applications) and large floorstanding speakers.
The pre-amp section uses a fully-balanced TEAC-QVCS high-precision volume control circuit with a
4-circuit construction. By maintaining detail levels at all resolutions, the AI-503 creates a very realistic
soundstage, along with a high signal-to-noise ratio and excellent sense of space. By connecting an
external power amplifier to the fitted pre-out jacks, you can upgrade performance and create an even
more capable audio system. The headphone amp section uses a discrete TEAC-HCLD circuit, with a
push-pull arrangement, allowing it to drive even high-impedance headphones with ease. The
two-stage High/Low gain switch enables optimal volume setting for everything from low-impedance
in-ear monitors to high-impedance (600Ω) on-ear headphones. Furthermore, the inclusion of a 3.5mm
headphone jack, one that supports a 4-pole separate ground connection, allows excellent channel
separation, even when using balanced-type headphones or earphones.

DAC/preamp with dual mono structure

■ High-performance VERITA AK4490 DACs support 11.2MHz DSD and 384kHz/32-bit PCM

For the DAC chips, the key to high-performance digital audio, we used the
highly-regarded VERITA AK4490* DACs, made by Asahi Kasei Microdevices
Corporation. Along with native playback of 11.2MHz DSD signals through direct
processing, a wide range of high-resolution audio sources (including
384kHz/32-bit PCM digital input) are supported. These DACs enable the
reproduction of the finely etched detail and outstanding sense of stereo
placement that are the hallmarks of quality high-definition high-resolution audio sources.

*The AK4490 is a member of the Asahi Kasei Microdevices
Corporation Audio4proTM family brand of products developed for
professional audio devices and high-end digital audio
applications.

■ Dual-mono configuration supports fully-balanced transmission
As well as helping deliver class-leading levels of power, the sophisticated dual-mono configuration also
extends to the D/A converter and the preamp.

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Product information

The dual-mono layout incorporates two completely independent mono circuits for the left and right
channels. Starting with the high-performance VERITA AK4490 D/A converters, this arrangement
provides outstanding isolation between the two channels. The suppression of interference between the
left and right channels is particularly important when it comes to headphone listening.

■ Pre-amp section provides fully balanced transmission and uses TEAC-QVCS high-precision volume

control circuit
For the preamp circuit, we have utilized the TEAC-QVCS (Quad Volume Control System), an ingenious
circuit with a fully-balanced design. It allows balanced processing of the audio signal at every stage,
from immediately after digital-to-analog conversion until the signal
reaches the volume amplifier.
Control signals, transmitted from the volume knob, simultaneously
adjust the variable-gain amplifier-type volume controls of four
independent circuits — providing a positive and negative for both 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 until a point immediately before the
power amplifier, achieving a clear sound quality with outstanding channel separation. (This process
only applies to balanced analog inputs).
What’s more, "gang errors" (level discrepancies between left and right channels at low volumes),
which can be a particular issue during headphone listening, have been completely eliminated, so you
can enjoy accurate audio even when using low-impedance in-ear monitors.

■ Pre-outs can be connected to both power amplifiers and active speakers
The AI-503 can also be used as a high-quality preamp. As the volume from the RCA output jacks can
be varied, you can achieve a seriously upgraded audio system simply by connecting a power amplifier
to the pre-out jacks. In addition, the unit has a pair of analog RCA input jacks, so you can also connect
an analog turntable with a built-in phono EQ amplifier, such as a TN-350 or TN-570, a cassette deck,
or other analog equipment.

■ Built-in 44.1kHz and 48kHz clocks

The AI-503 supports asynchronous transfer mode when connected by USB, allowing it to control PCM
and DSD signals by synchronising them with its own clock (generated by a high-precision crystal
oscillator) rather than synchronising with a computer clock signal that is invariably unstable and noisy.
Two dedicated internal clocks (running at 44.1kHz and 48kHz) are built in. By clocking signals that are a
multiple of the clock frequencies to an audio-grade, high-precision crystal oscillator, featuring inherently
low phase noise, the damaging effects of jitter on audio quality can be largely suppressed and the audio
source can be reproduced more faithfully.

■ Filter types include 4 PCM and 2 DSD digital filters

Filter types include 4 PCM and an ‘off’ mode , as well as 2 DSD digital filters. You can use the remote
control to set the optimal filter, according to the input file format and type of music. You can also change
the filter during music playback so that you can fine-tune the audio quality.

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