TEAC AI-301DA Integrated Amplifier Dac & Bluetooth

 AI-301DA

This product signals the beginning of a new chapter for TEAC, with both high-resolution audio and Bluetooth® playback in a single-box product

Main Features

Compact, with USB input and fully compatible with high-resolution DSD

Capable of 5.6MHz DSD native playback

The USB input facility allows DSD native playback which converts 5.6MHz DSD files directly into analog signals without needing first to convert it to PCM. It supports both the ASIO2.1 and DoP (DSD over PCM) conversion methods. Using the AI-301DA in conjunction with the TEAC HR Audio Player* high-resolution playback computer software application, anyone can easily explore the world of high-rez digital audio, including 5.6MHz DSD or 32bit/192 kHz PCM files, without struggling to have to understand complex settings etc. 

Asynchronous mode-capable USB input

When receiving digital audio signals from a computer via USB cable, the unit can operate in asynchronous mode, controlling the timing of the input signal using the UD-301's internal clock (which is identical to the one used in the UD-501). With asynchronous transmission over USB, signal compromising jitter is effectively eliminated, allowing digital audio signals to be transmitted in a pure, unadulterated state.

Coaxial and optical digital inputs offer versatility

Besides its a USB audio input, the AI-301DA is also fitted with S/PDIF inputs for maximum compatibility. The coaxial digital input supports up to 24bit/192kHz while the optical digital input supports up to 24bit/96kHz digital audio.

Wireless playback at high sound quality via Bluetooth® using the aptX® codec

The AI-301DA supports the aptX® codec which offers high sound quality wireless playback capability via Bluetooth® hardware. Besides high quality sound, the aptX® codec also offers low latency and an excellent error recovery function, both crucial features for achieving the best audio performance.

High-performance BurrBrown PCM1795 digital-analog converter

The BurrBrown PCM 1795 D/A converter converts 5.6MKz DSD or 32bit/192kHz PCM digital data into analog form. The analog signal, which is derived from huge digital audio data files (far larger than those used by CD) delivers a finely etched sound, with a great sense of depth.

ICEpower high sound quality Class-D amp circuit

The power amplifier stage is based upon a tried and tested Class-D amp, manufactured by ICEpower of Denmark. 

It converts a high-resolution sound source into high-definition speaker signals using a feedback loop between a hybrid feedback controlled oscillating modulator (HCOM) which faithfully amplifies the signal, and a multivariable enhanced cascade control (MECC). The efficient design of the 60W + 60W (4 ohms) amplifier creates very little heat, eliminating any need for a cooling fan, thus affording a quiet environment that's ideal for musical appreciation.

CCLC circuits provide high-quality headphone output

The 100mW + 100mW output (at 32 ohms load) headphone amplifier uses CCLC (Coupling Capacitor Less Circuit) technology. In ordinary headphone output circuits, a capacitor is used for output-stage coupling, and so the sound is unavoidably colored. When the capacitor is combined with a high-pass filter this often results in phase lags, or low frequency level degradation. With CCLC the negative impact of capacitors on sound quality is eliminated, providing full low-frequency sound and a responsive headphone listening environment with great spatiality.

Well-engineered aluminum enclosure, compact proportions

Following on from our development of the 501 series concept (small high-performance audio components that can be fitted on a desktop) we decided, at the outset, that the 301 series would be an even more compact design. Now, the casework has been shrunken to just 215mm wide, allowing greater freedom in positioning the amplifier. External highlights include aluminum panels and a motor-driven volume knob with the tactile feel you'd expect from controls found in high end full-size hi-fi components. At the same time, the solid enclosure underpinned by the metal chassis, is impressively inert, minimizing the effects of vibration on the unit's sound quality. 

Simple operation with Auto Power OnThe AI-301DA has a well-conceived Auto Power On function which automatically switches on the unit's power when it senses a digital signal input. When the amplifier is connected to optical digital audio output from a television set, just switching on the television turns on the power of the AI-301DA, enabling you to immediately enjoy high-quality sound without having to adjust any other settings. This facility makes life very convenient allowing users to switch on the TV and instantly listen to music or a soundtrack.

Combine with the LS-301 speakers to create a simple high-resolution systemCombining the AI301-DA, with its high-performance engineering packed into a compact body, and the LS-301 coaxial speaker, specifically developed to match it, creates a system that does full justice to any high-resolution audio source. 

What's more, the AI301-DA has been fitted with a sub-woofer pre-out plug so that the user can, if they wish, also employ the equally compact 2.1ch LS-WH01 satellite/subwoofer system, ,making for an extraordinarily compact 2.1ch system that can easily be placed on a desktop or next to a TV set. 

Features at-a-glance
ICEpower 50ASX2-SE Class-D power amp
60W + 60W (4 ohms) high output
2.8MHz/5.6MHz DSD native playback (via USB input)
32bit/192kHz PCM file playback
Asynchronous mode capability
BurrBrown PCM1795 digital-to-analog converter
Bluetooth® playback with aptX codec
Memory capacity for up to a maximum of eight Bluetooth® device pairings
CCLC headphone output circuit
Full metal housing
One USB input (USB-B type)
One coaxial digital input
One optical digital input
Two RCA stereo line inputs
Screw-type speaker terminals (banana plugs, AWG8 guage cable compatible)
Headphone output (standard stereo jack)
Subwoofer output (RCA)
Aluminum motor-driven volume control
Three-pin IEC AC power socket
Customized remote control included
Auto Power On function (activated by digital signal sensing)
Auto Power Save function

AI-301DA SPECIFICATIONS
DAC Section    
D/A Converter    BurrBrown PCM1795
Bluetooth® Section    
Bluetooth® version    V2.1 + EDR
Output    Class 2
Compatible profiles    aptX®, A2DP, AVRCP
Output    
Connector    Screw-type (banana terminal plugs, AWG8 guage loudspeaker cable compatible)
Maximum output    60W + 60W (4 ohms, 20Hz to 20kHz, JEITA)
30W + 30W (8 ohms, 20Hz to 20kHz, JEITA)
Rated Output    43W + 43W (4 ohms, 20Hz to 20kHz, THD 0.1%, JEITA)
22W + 22W (8 ohms, 20Hz to 20kHz, THD 0.1%, JEITA)
Supported Impedance    4 ohms to 8 ohms
Analog audio input    
Connector    RCA jack
Digital audio inputs    
USB    
Connector    USB B-type (USB2.0)
Transmission mode    Asynchronous mode
DSD data 
sampling frequency    2.8M/5.6M Hz
PCM data 
sampling frequency    32k/44.1k/48k/88.2k/96k/176.4k/192k Hz
Bit rates    16/24/32bit
COAXIAL    
Connector    RCA jack
PCM data 
sampling frequency    32k/44.1k/48k/88.2k/96k/176.4k/192k Hz
Bit rates    16/24bit
Input level    0.5Vp-p
Input impedance    75 ohms
OPTICAL    
Connector    Optical digital connector
PCM data 
sampling frequency    32k/44.1k/48k/88.2k/96k Hz
Bit rates    16/24bit
Input level    -24 to -14.5dBm peak
Headphones output    
Connector    6.3mm(1/4") stereo phone jack
Maximum output    100mW + 100mW (with 32 ohms load, 1kHz)
Distortion rate    0.005%
Power supply    
USA/Canada    AC 120V, 60Hz
Europe    AC 230V, 50Hz
Power consumption    38W
Dimensions
(including protrusions)    215(W)×61(H)×254(D)mm
8.5"(W)×2.4"(H)×10"(D)
Weight    2.1kg 
4.6 lbs
Accessories    Power cord, remote control (RC-1313), AAA batteries for remote control×2, User Manual (including Warranty)

Audio performance
Frequency response    2Hz to 100kHz (-5dB)
S/N ratio    95dB(LINE Input, IHF-A/LPF 20kHz 1kHz 2V Input)
Distortion    0.01%(1kHz, 8 ohms, 1W)

AI-301DA SPECIFICATIONS

The AI-301DA is a versatile amp that will play hi-res formats and more. Adrian Justins' problem is deciding which room to use it in

Once upon a time if you mentioned the words computer and audiophile in the same sentence you would have been chased out of town. Those days are long gone and thanks to hi-res audio downloading there’s now a turf war going on for ownership of your desktop by hi-fi manufacturers eager to cash in with products that deliver maximum sonic satisfaction for those of us who like to listen as we learn or earn.

Understanding hi-res formats can be more daunting than deciphering the Da Vinci code in Nooksack, but one thing that is incontrovertible is that owning DSD files and not having an external DAC is like owning an E-type and keeping it in the garage. One such example is the AI-301DA, which boasts a Burr-Brown PCM1795 DAC and an asynchronous USB input. It’s also a Class D amplifier with a subwoofer pre-out and has a slew of inputs that could well see the unit gainfully employed in a living room alongside a TV, DVD or CD deck.

The AI-301DA has a few other tricks up its sleeve, including a built-in headphone amplifier and aptX Bluetooth for the first time on a Teac amp. Another nice touch is that Teac provides free software, called Teac High Res Audio Player, which extracts those DSD files out of your computer and passes them on to the DAC.  

If you use your computer within a USB cable’s length of the TV or CD player you’re well placed to take advantage of all of the AI-301DA’s talents. Just remember if you want to extract every last bit of sonic goodness out of any computer-stored hi-res files you need a cabled connection with the AI-301, as Bluetooth wireless is not up to maxing your hi-res music files. If Teac had opted for AirPlay as well as or instead of Bluetooth, we’d be talking about wirelessly streaming hi-res files.

Whichever setup you plump for you’ll be listening to the unit’s 80W Class D power amp, made by ICEpower of Denmark. This uses a hybrid feedback oscillating modulator and a multi-variable enhanced cascade control, which minimises heat generation sufficiently to negate the need for a cooling fan.

The amp is styled in classical component form, but has pleasingly compact dimensions (just 215mm wide). Design-wise it successfully straddles hi-fi, computer audio and living room domains without seeming too brash, too minimalistic or looking like it’s been knocked together in someone’s garage. It feels reassuringly solid and inert and has a nicely milled motor-driven volume knob.

The front power button clicks pleasingly when pressed and the input LEDs light up unambiguously to tell you which source is in use. If used with a TV or deck across a room chances are you’ll struggle to decipher the light show but you can use the dinky handset, which is plasticky but seems durable and thankfully has dedicated buttons for each input. You’ll probably also need the remote in a desktop setup as the volume level can’t be adjusted using a computer keyboard (although you can manually drag the volume slider within iTunes).

The 6.35mm headphone jack will connect your cans to a dual 100mW output (at 32ohms load) while the back of the AI-301DA provides just enough space for the slew of digital and analogue inputs comprising two pairs of RCA phonos, a digital optical input and a coaxial input, the latter two offering 24/192 and 24/96 compatibility respectively.

The heavy duty speaker terminals are banana plug-compatible and made from plastic-covered metal. A subwoofer pre-out, USB service port and USB type B completes the impressive jack pack. In asynchronous mode the latter USB eliminates jitter by bypassing the computer’s inferior internal clock.

The aforementioned Burr-Brown PCM1795 DAC eats 5.6MHz DSD and 32-bit/192kHz PCM signals for breakfast, should you choose to cook some up via the USB input. This allows native DSD bit streaming and converts 5.6MHz files directly to analogue signals without the need to first convert them to PCM, although it also supports DoP (DSD over PCM) conversion.

If using the unit for soundbar duties there’s a handy auto-on function, so turning the TV on will kickstart the amp into life from its snoozing state, and vice versa.

Using a USB connection and the Teac HR Audio Player software you may think all your hi-res troubles are over, but that is not quite the case. On a Mac the software is easy to download and install as no additional drivers are required. It’s also a cinch dragging and dropping files to create and save playlists, but (unlike other software such as Audirvana) file compatibility eschews all of Apple’s formats. So while you can play DSD (2.8 and 5.6), FLAC and MP3 via the HR Audio Player, you have to use iTunes for M4A, AIFF and ALAC, as well as DXD WAV files. You also need to manually switch the audio output to USB or back again using the computer’s sound preferences and may have to tinker with the frequency settings using the Audio MIDI utility. As such, it’s a shame the AI-301DA doesn’t have an LCD display that tells you the incoming format, bit rate and sampling frequency.

Sound quality

The AI-301DA can muster two channels at 40W (claimed) and has enough in its tank to comfortably drive a pair of speakers with an impedance between four and eight ohms. Going straight in for the kill I am blown away by the clarity and openness of my DSD collection. The violins and cellos in Vivaldi’s Concerto in D minor opus 4 no.8 Allegro have an energy and vitality that almost penetrates my joints. The mid-range simply shines and the low frequencies are mesmerisingly smooth. Compared with a standard resolution version the piece is much more beguiling and I am happy to listen to it repeatedly in a way that I’d never do otherwise.

Dropping down a resolution notch or two to a 24/96 FLAC download of Steely Dan’s Time Out Of Mind is still totally engaging with a punchiness that’s normally absent when listening through a built-in computer DAC or speakers. Donald Fagen’s vocals are airy and resonant and the percussion has an unexpected dimensionality about it that seems to come from above.

Fantasia on Greensleeves, another hi-res FLAC download, shows the AI-301DA has a deftness of touch with sumptuous strings that are immaculately timed, grabbing me by the emotional collar and carrying me away to a leafy meadow. I can almost taste the cucumber sandwiches before I am rudely awakened by a bit of head-thumping bass from Lorde and her Royals. This time I listen via Bluetooth and as pleasingly coherent as it is, with no loose or woolly bass notes I don’t feel the same spine-tingling quality to her vocals as I do with better-quality formats.

The gap between wireless and hard-wired connections is proven by a comparison of CD and Bluetooth versions of Diana Krall’s My Love Is. The latter is decent and has plenty of verve and gusto, but there’s a small but significant increase in detail with the CD version. Krall’s seductive vocals are a touch more resonant and the double bass twangs that much more so that the long low notes hang tantalisingly as you sense the air vibrating around the strings. 

Teac’s choice of a digital amplifier rather than a Class A/B one means the AI-301DA has an inherently clinical edge to its sound. This seems to matter less with higher quality sources than it does with more compressed ones, but it can be quite unforgiving with low bit-rate music streamed from Spotify or vTuner internet radio, where holes in the dynamic range are dissatisfying. 

Conclusion

There’s an awful lot to like about the AI-301DA, especially the way it handles DSD files over USB by combining flawlessly with the Teac HR Audio Player software. It’s a shame the software can’t handle Apple’s own hi-res formats, but you can revert to iTunes where necessary.

The amp is excellently built, looks the part and is highly versatile in terms of its file handling and source compatibility, although its lack of AirPlay or Ethernet makes it more limited when used in a living room situation. Still, given the highly reasonable price it makes a more than compelling case for itself as a desktop amp for the computer-using audiophile generation.

LIKE: Good design; DSD handling; inputs
DISLIKE: iTunes incompatibility; clinical digital sound; no AirPlay/wi-fi
WE SAY: Superb with hi-res; versatile enough to use in the living room and compact

DETAILS
PRODUCT Teac AI-301DA
ORIGIN Japan
TYPE Integrated amplifier with USB DAC and Bluetooth
WEIGHT 2.1kg
DIMENSIONS (WxHxD) 215 x 61 x 254mm 
FEATURES
• 2x 40W Class-D power amplifier
• 2.8MHz/5.6MHz DSD native playback; 32bit/192kHz hi-res
• Burr-Brown PCM1795 DAC
• aptX Bluetooth

笔者第一眼看到TEAC AI301DA时，简直傻了眼：这不就是一台耳放吗？然而，这台占地不足一个地板方砖大小的桌面D类功放，能够同时兼具DSD文件支持直接输出、RCA信号输入和手机蓝牙控制功能，能够满足多种媒体音乐的高品质播放要求。

对于一个新婚不久的两小口家庭来说，也许要购置一整套Hi-End功放可谓是天方夜谭。然而，并不是说工薪阶层或者小白领家庭就没有享受高质量并且价格合理的权利。相反，随着科技的日新月异，那些当年要用高昂价钱换来的视听享受，在今天能够在越来越广泛的人群中得到普及。体积娇小、功能齐备、质量上乘又价格合理的功放绝对能够打开大众消费者市场。笔者发现，TEAC AI301DA就是不二之选。

笔者第一眼看到TEAC AI301DA时，简直傻了眼：这不就是一台耳放吗？然而，这台占地不足一个地板方砖大小的桌面D类功放，能够同时兼具DSD文件支持直接输出、RCA信号输入和手机蓝牙控制功能。对于收入普通的家庭来说，这样一台价位大概是两三千人民币左右的功放能够满足多种媒体音乐的高品质播放要求。

娇小玲珑 功能齐全

随着DSD文件下载网站的普及，越来越多音乐爱好者接受这种高质量的流媒体播放技术。而TEAC AI301DA则很好地迎合了这个需求。这台机器的USB接口能够把原始DSD文件转为模拟信号。它支持ASIO2.1和DoP两种DSD转换模式。通过其官方网站下载的特定播放软件，人们能够方便简单地播放5.6MHz的DSD文件或者PCM 32bit/192kHz文件。

当机器通过USB插口接收到数码信号后，通过它内部时钟控制信号输入。通过非同步的数据处理，信号的流失能够减到最低，这样数码信号就能够转换成高度纯净的无损信号了。DSD的文件数据比CD要大得多，然而本机使用的BurrBorwn PCM 1795 D/A转换器，能够把DSD文件转化成高质量的模拟信号，让声音变得更加有层次感。

然而，DSD音乐文件的下载和直接播放依然不是我国当前的主要聆听音乐方式。如果说这部机器的DSD文件播放是“高大上”的欣赏模式的话，那么时下非常流行的蓝牙手机配对播放就是一种更加接近地气的玩赏模式了。此机采用aptX技术接收手机蓝牙信号，能够有效地降低数据错误失真。

对于时下很多年轻人来说，为了不干扰其他人的作息，很多时候选择耳机聆听音乐。而作为一台桌面D类功放，耳放功能的质量将直接决定其市场销量的成败。这台机子最大的特点是使用一种特殊的耦合电容干扰处理技术，把耦合电容造成的低频相位失真减少到最低。

总体来说，对于中档要求的发烧友来说，这台功放也能满足他们的听觉标准。此机在一个性能极好的级联控制（MECC）和混合反馈控制的震动调节器（HCOM）之间有一个反馈回路，保证了高分辨率音源。此机的放大器采用D类放大技术，产生的热量非常低，这样就可以省下降温电扇的位置，从而降低器材制造的噪音了。

音色出众 声场宽广

笔者通过某国外DSD下载网站花了几美元下载了一张阿姆斯特丹小交响乐团演奏勃拉姆斯和勋伯格作品集的SACD。笔者很轻易地把文件拖入这部机器的指定播放软件，点击“播放”就能够开始播放了。为了挑战这台细小机器的极限，笔者特意使用PSB Imagine X2T音箱进行搭配。

让人感到意外的是此机产生的音质远胜于我们心目中的“D类”产品印象。勋伯格的《升华之夜》呼吸感强烈，仿佛一个有错落有致的机织体在试音室的黑暗深处呼吸吐纳。不同声部弦乐之间的缠绵和纠结不但没有让人觉得凌乱，反而让听者认清整部作品的结构肌理和编排布局。

笔者再尝试一些国内流行的网络流媒体播放软件，此机器也有不俗表现。我用其中一款即时通讯工具附带的一款音乐播放软件播放日本经典歌后美空云雀的著名歌曲《川流不息》，只听见歌后低沉厚实的声音吐字清晰，气息逼真，仿佛歌唱家就站在面前一般。此机低音圆润，中音有力，高音清晰甜美不刺耳，该有的细节都能够完整地呈现出来。

接上RCA信号线后，笔者插入一张Ensamble的杂锦试音碟，只见第一轨的埃尔加管乐小品《Molley on the Shore》从弱奏到高潮，错落有致，敲击乐与管乐的对答方位感清晰明朗，乐曲中不断爆起的小高潮在TEAC AI301DA的推送下铿锵有力，效果逼真。

总结

这是一台价格合理，功能齐备，效果卓绝的D类桌面功放，而且它能够满足的需求绝不仅限于一台桌面功放应有的功能。对于家居环境拥挤，而且希望家电用品尽量简洁的现代人来说，这种器材实在是最佳的不二选择。