Teac AI-303 - Amplifier Manual

Included accessories

Using the TEAC International Site

You can download updates for this unit from the TEAC
International Site: https://teac.jp/int/
Click LANGUAGE at the top right of the page and select the desired language to access a page in the corresponding language.

Before use

Placement precautions

• Do not install this unit in a location that could become hot. This includes places that are exposed to direct sunlight or near a radiator, heater, stove or other heating equipment. Moreover, do not place it on top of an amplifier or other equipment that generates heat. Doing so could cause discoloration, deformation or malfunction.
• You may stack this unit with a PD-301 or UD-301. However, place this unit on top in order to improve heat dissipation.
• When installing this unit, leave a little space (at least 5 cm or 2") between it and walls and other devices in order to allow good heat dissipation.
  If you put it in a rack, for example, leave at least 5 cm (2") open above and 10 cm (4") open behind it. Failure to provide these gaps could cause heat to build up inside and result in fire.

Maintenance
Wipe dirt from the top cover and other panel surfaces using a soft cloth that has been slightly dampened with a diluted neutral cleanser.
Do not wipe with chemical cleaning cloths, thinner or other chemical agents. Doing so could damage the surface.
For your safety, disconnect the power cord from the outlet before cleaning.

Using the remote control

Precautions for use
Misuse of batteries could cause them to rupture or leak, which might result in fire, injury or the staining of nearby materials. Please carefully read and observe the precautions.

• When using the remote control, point it toward the remote control signal receiver on the main unit from a distance of 5 m (16 ft) or less. Do not place obstructions between the main unit and the remote control.
• When not using the remote control for an extended period of time, remove the batteries to prevent leakage.

Installing batteries
Remove the cover from the back of the remote control and insert two AAA batteries with their ¥/^ oriented as shown in the case. Replace the cover.

When to replace batteries
If the distance required between the remote and the main unit decreases or if the unit stops responding to the remote buttons, replace both batteries with new ones. Dispose of the used batteries according to the instructions on them or requirements set by your local municipality.

Connections

Complete all other connections before turning the unit on

• Carefully read the manuals of the devices that you are connecting and follow their instructions when making connections.
• Do not bundle connecting cables with power cords. Doing so could cause noise.
• Connect all plugs completely.

Connecting speakers

Notice about the European model
In accordance with European safety regulations, connecting banana plugs to speaker terminals is not allowed on European models. The holes into which banana plugs could be inserted have been covered with black caps. Connect speakers using bare wires or spade lugs. If a black cap should become separated from its terminal, return it to its original position.

Precautions when making connections

• After all other connections are complete, connect the power cord's plug to a wall outlet.
• Carefully read the manuals of the devices that you are connecting and follow their instructions when making connections.

ATTENTION

• Check the impedance of your speakers. Connect speakers with an impedance of between 4 Ω and 8 Ω. If speakers with different impedance ratings are used, the protection circuit could operate, causing sound output to stop.
• The red speaker terminals are positive (+) and the black speaker terminals are negative (–). Generally, the + wire of the speaker cable is marked to distinguish it from the – wire of the cable. Connect the marked wire to the red + terminal and the unmarked wire to the black – terminal.
• If the exposed core wires at the tips of the speaker cables should touch other cables or terminals, an electrical short might occur.
  Never allow speaker cables to cause a short.
• To prevent hum and noise, avoid bundling the cables together with the AC power cord or other cables.

How to connect speakers

Connecting with banana plugs
You can also make connections using commercially-available banana plugs. First, connect the banana plugs to the speaker cables and then connect the plugs to the terminals.

• Keep the caps tightened when in use.
• Carefully read the instructions for the banana plugs that you are using.

1. Standby/on () butto
   Press this to turn the unit on and put it in standby. When the unit is turned on, the ring around the button lights blue.
   • When this unit is in standby mode, it consumes standby power. For this reason, we use the term "standby" rather than "off".
2. PHONES jack
   Connect a 3.5mm (1/8") stereo mini plug for headphones here.
   
   • This headphone amp circuit uses a four-pole connector with independent left and right for grounding. Ordinary plugs with 3 or 4 poles can be used.
   • If headphones are connected here, audio will not be output from the speaker (SPEAKERS) terminals or SUBWOOFER OUT connector on the back of the unit.
     Use this button to select the input source.
3. Input source indicators
   The indicator for the source that is selected lights.
   These indicators blink when an input signal is not input properly.
   This unit can play back linear PCM signals. It cannot play back Dolby Digital, DTS, AAC and other formats. Set the source device to linear PCM output.
4. Remote control signal receiver
   This receives signals from the remote control. When operating the remote control, point it at the remote control signal receiver.
5. CROSSFEED knob
   Turning this right will increase the amount that the left and right sound signals are each mixed into the other channel, making the overall sound more centralized in the stereo field. Turning this all the way to the right will make the sound mono. Turning this all the way to the left will turn this function off.
6. VOLUME knob
   Use this to adjust the volume. Turn it right to increase and left to decrease the volume.

Remote control parts and functions

You can control both this AI-303 and a PD-301 using the RC-1337 remote control. Only the buttons used for the AI-303 are explained in this document.

1. MUTE button
   Press this to mute the sound temporarily. To restore the sound, press it again.
2. Standby/on () button
   Press this to turn the unit on and put it in standby.
3. Input source selection buttons
   Use these to select the playback source.
4. VOLUME (−/+) buttons
   Use these to adjust the volume.
5. UPCONVERT button
   Press this to change the upconversion setting.
6. FILTER button
   This changes the digital filter type.
7. DISPLAY button
   This shows the playback sampling frequency (Fs).

Basic operation

1. Press the standby/on () button to turn the unit on.
   
2. Press the SOURCE button to select the input source.
   Each time the SOURCE button is pressed, the source changes as follows:
   
   The indicator lights for the selected source.
   

• The input source indicators blink when the input signal is a digital audio format (such as Dolby Digital, DTS or AAC). If this is the case, check to see if the connected digital audio output device has a "PCM" setting for the digital output format. Refer to the operation manual for that device to make this setting.
• When using this unit with a Windows computer, before setting this unit to USB and playing back audio files on the computer, you must install the dedicated driver on that computer.

3. Operate the audio output device.
   Refer to the operation manual of the audio output device that you are using.
4. Adjust the volume.
   Turn the VOLUME knob or use the VOLUME buttons on the remote control to adjust the volume to the appropriate level.
   

MQA (Master Quality Authenticated)

MQA is an award-winning British technology that delivers the sound of the original master recording. The master MQA file is fully authenticated and is small enough to stream or download.
Visit mqa.co.uk for more information.
The AI-303 includes MQA technology, which enables you to play back MQA audio files and streams, delivering the sound of the original master recording.
The state of the MQA indicator shows whether the unit is decoding and rendering an MQA stream or file, guaranteeing that the sound is identical to that of the source material. When the MQA indicator lights blue, this shows that the file playing is an MQA studio file that has either been approved in the studio by the artist/producer or has been verified by the copyright owner.
A reddish purple color shows that the unit is rendering an MQA stream or file. The final expansion of MQA files is undertaken.

• This unit can decode and render MQA streams and files only when the playback source is USB, HDMI (ARC), COAXIAL or OPTICAL.

Indicator during MQA playback

Crossfeed function

• By using the crossfeed function when listening through headphones, a sound that is closer to the sound heard from speakers can be re-created. In particular, this can improve appreciation of music recorded with extreme left and right channel separation, which was common in the early days of stereo recording, as well as when listening for extended periods.
• When using speakers, the sound image will be focused toward the center of the stereo field. This has the effect of making vocals and narration clearer and easier to understand.
• Turn the CROSSFEED knob all the way to the left to turn off the crossfeed function and use ordinary stereo playback. Turning this all the way to the right will focus all the sound to the center and make it mono.

HDMI (eARC)

By using a single HDMI cable to connect the HDMI connector of this unit to the ARC connector of a TV that supports ARC (Audio Return Channel) or eARC (Enhanced Audio Return Channel), digital audio (up to 192kHz/24-bit) from the TV or player connected to the TV can be output from the speaker and headphone jacks of the AI-303.
Since HDMI CEC is supported, the TV remote control can be used to adjust the volume of this unit and mute it. In addition, the power of this unit can be linked to turning the TV power on/off (standby).

• HDMI CEC support commands differ according to the TV, so synchronized operation with all TVs is not guaranteed.
• This unit complies with the eARC (Enhanced Audio Return Channel) specification, but it does not support the decoding of Dolby Atmos®, Dolby TrueHD, DTS:X™, DTS-HD and other formats. Set the audio output of the TV to linear PCM before connecting.
• The digital audio signals that can be output varies by TV. Even if a Blu-Ray Player or other playback device outputs high-resolution audio signals, the TV might restrict resolution to 48kHz/16-bit. For details, check with the manufacturer of the TV that you are using.
• If you want to link power supply for the unit with turning on a TV, turn off the automatic standby function.

Bluetooth® wireless technology

Bluetooth® notes
When using this unit with a mobile phone or other Bluetooth devices, they should be no more than about 10 m (33 ft) apart.
Depending on the circumstances of use, however, the effective transmission distance might be shorter.
Wireless communication with every device that supports Bluetooth wireless technology is not guaranteed. To determine the compatibility between this unit and another device that supports Bluetooth wireless technology, refer to that device's operation manual or contact the shop where you purchased it.

Content protection
This unit supports SCMS-T as a form of content protection when transmitting audio, so it can play protected audio.

Transmission security
This unit supports security functions during Bluetooth wireless transmission in accordance with the Bluetooth standard specifications, but it does not guarantee the privacy of such transmissions.
TEAC CORPORATION will bear no responsibility should an information leak occur during Bluetooth wireless transmission.

Profiles
This unit supports the following Bluetooth profiles. o A2DP (Advanced Audio Distribution Profile) o AVRCP (Audio/Video Remote Control Profile)
In order to transfer audio using Bluetooth wireless transmission, the Bluetooth device must support A2DP. In order to control playback on the Bluetooth device, it must support AVRCP.
Even if a Bluetooth device supports the same profiles, though, its functions might differ according to its specifications.

Codecs
This unit supports the following codecs. It will automatically select one that is appropriate for the other Bluetooth device during audio transfer.

• LDAC
• LHDC
• Qualcomm® aptX™ HD audio
• Qualcomm® aptX™ audio
• AAC
• SBC

1. Press the standby/on (¤) button to turn the unit on.
   
2. Press the SOURCE button one or more times to select Bluetooth ().
   This puts the unit into Bluetooth mode.
   
3. Pair or connect with another Bluetooth device.
   Pairing with another Bluetooth device
   The first time another Bluetooth device is used with this unit, they must be paired.
   To prepare this unit to pair, put it into Bluetooth mode and press the SOURCE button or remote control button for at least three seconds. When this unit is ready to pair, its indicator flashes rapidly.
   After this unit enters pairing mode, pair with it (shown as AI-303) on the other Bluetooth device. The indicator stops flashing and stays lit when pairing completes and they are connected. For details, refer to the operation manual of that Bluetooth device.
   To connect with a Bluetooth device that has already been paired, follow the connection procedures for that device.

• When pairing or connecting, devices should be within a few meters of each other. If they are too far apart, pairing and connection afterwards might become impossible.
• If you want to delete pairing data and initialize the Bluetooth circuit, press the SOURCE button or remote control button for at least 10 seconds. At this time, all input indicators will flash twice.

ATTENTION
Regardless of the connection standby states of this unit and the other Bluetooth device, if the Bluetooth indicator continues blinking for a long time, turn off both this unit and the other device. Then, restart them and conduct connection procedures again.

4. Start audio output on the other Bluetooth device.

• Confirm that the volume is turned up on the other Bluetooth device. If the volume of the audio being output is not turned up, no sound might be output from this unit.

5. Adjust the volume.
   

• The volumes of this unit and the other Bluetooth device are not linked. This unit cannot control the volume of the other Bluetooth device, and that device cannot control the volume of this unit.

NOTE

• You cannot select the codec to be used by pressing a button, for example.
• Due to the characteristics of Bluetooth wireless technology, compared to the playback on the Bluetooth device, audio output through this unit will be slightly delayed.

Checking the Bluetooth audio codec
The audio codec being used for Bluetooth playback is shown by the green indicator.

Support for multipoint connection
Connecting with 2 Bluetooth devices at the same time is possible. Audio can only be output from one at a time when connected. Output from the device that most recently started playback will be prioritized. Playback will be stopped on the previously playing device.

LDAC is an audio coding technology developed by Sony that enables the transmission of High-Resolution (Hi-Res) Audio content, even over a Bluetooth connection.
Unlike other Bluetooth compatible coding technologies such as SBC, it operates without any down-conversion of the Hi-Res Audio content*, and allows approximately three times more data** than those other technologies to be transmitted over a Bluetooth wireless network with unprecedented sound quality, by means of efficient coding and optimized packetization.
* excluding DSD format contents
** in comparison with SBC (Subband Coding) when the bitrate of 990 kbps (96/48 kHz) or 909 kbps (88.2/44.1 kHz) is selected

Energy-saving functions

This product has energy-saving sleep and standby states.
The operation of these functions depend on the automatic standby setting and the selected input source.

Sleep overview
Only when the input source is USB, HDMI (eARC), Bluetooth, COAXIAL or OPTICAL
If there is no digital input signal from the selected source and no operation occurs for about three minutes, the unit will enter sleep mode.
Inputting the selected digital signal will wake the unit (automatic power on function).

• When in sleep mode, the input indicators will light dimly.

When the automatic standby function is on
The unit will enter standby mode after about 30 minutes if it remains in sleep mode or if there is no sound when the input source is LINE. When in standby mode, inputting the selected digital signal will not turn the unit on again.
Press the standby/on () button on the main unit or the remote control to turn the unit on again.

• Power consumption in standby mode is 0.5 W or less.
• The automatic standby function is on by default when the unit is purchased.
• To always use the automatic power on function triggered by digital signal input, follow the procedures below to turn off the automatic standby function.

Checking procedure
If the automatic standby function is off, all the input indicators will light temporarily when the unit is turned on.

Setting the automatic standby function
When the unit is in a standby state, press and hold the standby/on () button. After about three seconds the input indicators will change as shown below and the automatic standby setting will change.
From all lit to two flashes: automatic standby function on
From the current input indicator lit to all indicators lit: automatic standby function off

Playing back music on a computer

Operating systems that have been confirmed for use
We provide information about operating systems that have been confirmed for use on the product web page at the following URL.
https://teac.jp/int/product/ai-303/

Installing the driver
When using Mac
This unit can be operated with the standard OS driver, so there is no need to install a driver.
A dedicated driver must be installed on the computer, however, to use Bulk Pet.

When using Windows
The dedicated driver must be installed on the computer.

Installing the driver on a computer
Install the dedicated driver on the computer after downloading it from the following URL.
For details about installation and OS setting procedures, see the installation guide included with the driver.
https://teac.jp/int/product/ai-303/download

Notes about transmission modes
This unit can transfer data using Isochronous or Bulk Pet mode.
The sampling frequencies that can be transmitted are 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz, 352.8 kHz and 384 kHz.
2.8MHz, 5.6MHz and 11.2MHz DSD are also supported.
When properly connected, you will be able to select "TEAC USB AUDIO DEVICE" as the audio output for the operating system.

Downloading playback application TEAC HR Audio Player
You can download Mac and Windows versions of our free TEAC HR Audio Player application that supports playback of DSD files.
https://teac.jp/int/product/ai-303/download

Playing back audio files on a computer

1. Connect this unit to the computer using a USB cable.
   

• When a dedicated driver is necessary for connection, it must be installed on the computer beforehand.
• Use a cable that has a USB Type-C connector for connecting to this unit.

2. Turn the computer on.
   • Confirm that the computerhas started up correctly.
3. Press the standby/on () button to turn the unit on.
   
4. Press the SOURCE button repeatedly to select USB.
   
5. Start playback of an audio file on the computer.
   If you can adjust the volume from the computer, set it to its maximum level and use this unit's VOLUME knob to adjust the level for the best audio quality.

• If you are using the TEAC HR Audio Player application, the volume cannot be adjusted from the computer.

• The computer and this unit cannot control each other.
• Do not do any of the following when playing back audio files over the USB connection. Doing so could cause the computer to malfunction. Always quit the audio playback software before conducting any of these operations.
• Unplugging the USB cable
• Putting the unit into standby mode
• Changing the current input selection
• To avoid outputting computer operation sounds, change the settings on the computer.
• Connect the computer and this unit and wait until the driver has loaded properly before starting the audio playback software. When connecting for the first time or using a different USB port, driver loading could take some time.

Playback operations

Sampling frequency display during playback
Press the remote control DISPLAY button to show for a few seconds the sampling frequency (Fs) of the sound source playing back.

Digital filters
Press the remote control FILTER button to change the digital filter type.

• This setting has no effect when the input is DSD.

RDOT filter
RDOT is an analogous interpolation method, that uses fluency logic. This filter features re-creation of natural tones and sound space. With upconversion, 4 settings are available.

FIR filter
This FIR filter features short delay with slow roll-off. Compared to RDOT, the sound is warmer. Upconversion is disabled.

Upconversion
The upconversion function can be used with input sources other than analog audio.
Press the remote control UPCONVERT button to change this

• This setting only functions when the RDOT digital filter

The relationships between input sampling frequencies and sampling frequencies after upconversion are shown on the table below.

These values are not converted.

• The maximum upconversion is 8× Fs.
• Upconversion is not possible when the input is DSD.

Input indicator lighting
Pressing the DISPLAY, FILTER or UPCONVERT button on the remote control will cause the input indicator lighting to change, showing the state, as follows.

*These are shown at the same time.

Troubleshooting

If you experience a problem with the unit, please take a moment to review the following information before requesting service. If it still does not operate correctly, contact the retailer where you purchased the unit.

Since this unit uses a microcontroller, external noise and other interference can cause the unit to malfunction. If this occurs, unplug the power cord, wait for a while, and then turn the unit on again and restart operations.

Specifications

Amplifier
Rated output
25 W + 25 W. . . . . . 0.03% (LINE IN, 1 kHz, 8 Ω, JEITA)
50 W + 50 W. . . . . 0.03% (LINE IN, 1 kHz, 4 Ω, JEITA)
THD+N. . . . 0.008%
(LINE IN, 20 Hz – 20 kHz, 4 Ω, 6.25 W, JEITA)
THD+N. . . . . .. . 0.004% (LINE IN, 1 kHz, 4 Ω, 6.25 W, JEITA)
S/N ratio. . . . . . 100 dB (LINE IN, JEITA)
Frequency response. .. . . . . 2 Hz – 70 kHz
(LINE IN, –5 dB, JEITA)

Digital audio inputs
Coaxial digital connector. .. . . 1
Optical digital connector. . .. . . . . . . . . 1
Supported sampling frequencies
Linear PCM
32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz,
192 kHz (16/24-bit)
DSD. . . . 2.8 MHz
(supported using 176.4kHz/24-bit DoP transmission)
USB Type C port. . . .. . . . USB 2.0 standard
Supported sampling frequencies
Linear PCM
44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz,
352.8 kHz, 384 kHz (16/24/32-bit)
DSD. . . . . 2.8 MHz, 5.6 MHz, 11.2 MHz
HDMI. . . . . ARC/eARC 192 kHz/24-bit (PCM)

Analog audio inputs
RCA connectors. . . . . . . 2
Input impedance. . . . . . 10 kΩ

Bluetooth wireless technology
Bluetooth version. .. . . . . . 4.2
Output class. . . . . . Class 2
(transmission distance without obstructions*. . .. . 10 m)
Supported profiles. . . . . . . A2DP, AVRCP
Supported A2DP codecs. . . . . LDAC, LHDC,
Qualcomm®aptX™ HD audio,
Qualcomm®aptX™ audio, AAC, SBC
Supported A2DP content protection. . . . SCMS-T
Maximum number of stored pairings. . . . . . . . 8
Maximum number of multipoint connections. . . . . 2
* The transmission distance is approximate. The transmission distance could vary depending on the surrounding environment and electromagnetic waves.

Headphones output
Rated output. . . . . . 220 mW + 220 mW
(LINE IN, 32 Ω, 1 kHz, 1%, 25°C, JEITA)
THD+N. . . . . . . . . 0.006%
(LINE IN, 32 Ω, 1 kHz, 50 mW, JEITA)

General
Power supply. . . . AC 100–240 V, 50/60 Hz
Power consumption. . . . . . . . 33 W
External dimensions (W × H × D, including protrusions)
215 × 61 × 257 mm (8 1/2" × 2 1/2" × 10 1/8")
Weight. . .. . . 2.3 kg (5 1/8 lb)
Operating temperature range. . . . . +5°C to +35°C
Operating humidity range. . . . 5% to 85% (no condensation)
Storage temperature range. . −20°C to +55°C

Included accessories
Power cord × 1
Foot pads × 3
Remote control (RC-1337) × 1
Batteries for remote control (AAA) × 2
Owner's manual (this document, including warranty) × 1

• Specifications and appearance are subject to change without notice.
• Weight and dimensions are approximate.
• Illustrations in this owner's manual might differ slightly from production models.