ADL GT-40 Alpha DAC ADC Phono Headphone Amp

Very resourceful with excellent sound quality


SKU: GT40a

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Brian's comment

I have been using one of these for several months now and can thoroughly recommend it. It's versatility enables me to use it to test turntables (whether they have moving magnet or moving coil cartridges), line input devices (such as other dacs, other phono preamps), digital sources (via the USB input), and headphones. And the fact that it has a volume control means it can be directly connected to power amplifiers (thereby bypassing a separate preamp). So it is a real "jack of all trades" except that it masters them all - the sound quality is excellent. Its only limitation in my experience is the fact that it only has one set of RCA inputs.


Alpha Design Labs GT40a USB DAC with MM/MC Phono Stage and Headphone Amplifier

The GT40a is built for enthusiasts with growing music collections on their computer hard drives. It’s a high performance 24bit/192kHz USB DAC that’s amazingly affordable. Looking to convert your LPs or other analog sources to digital? The GT40a will take you to the podium with every album you archive.

The seriously-shielded audiophile-grade GT40a features a low-latency USB 2.0 audio driver that plays and records at 24bits/192 kHz. A likely first for this category, the GT40a includes a built-in low-noise MM / MC phono preamp! Record your favorite vinyl to hard disk via the USB output.

The ADL GT40a features L/R analog outputs, and switchable line or phono inputs with a vivid, captivating sound that is simply unheard of in this category.

The ADL GT40a (wired with ADLs Formula 2 USB cable of course!) brings Furutech’s signature sound -- smooth, detailed clarity -- to desktop systems, especially with high resolution 24bit/192kHz files, but even 16bit/44.1kHz files sound impeccable and very musical.




    • High performance 24bits/192kHz “VIA VT1736 “USB chip and 24bits/192kHz “Cirrus Logic CS4270” DAC /ADC chip
    • Enjoy audio in high resolution at 24bits/192kHz surpassing conventional 16bit/44.1KHz standards
    • Incorporates the most trusted driver in professional audio for 24bits/192kHz recording and playback
    • External power supply: while a USB-powered device might be convenient, it won’t develop the power required for high resolution playback, so we designed the GT40α with an external power supply to solve the problem.
    • Headphone Amplifier: It contains a high performance “Maxim MAX9722A” headphone amplifier with ample drive for good headphones
    • Analog-to-Digital Converter: The GT40α sports a high-performance ADC IC chip for high resolution recordings via analog inputs including phono, AM/FM radio, or other analog signals.
    • Convenient Clip signal Toggle switch for Recording Attenuation: Adjust the recording attenuation to avoid any distortion during recording: 0dB, 6 dB, or 12dB (RecAtt/db signal light comes on when input level exceeds circuit Gain).
    • Phono Preamplifier: A first for this class, the GT40α features a phono equalizer for recording your precious LPs. Switch between Moving Magnet (MM) and Moving Coil (MC) or Line input
    • Highest Quality Parts: The GT40α features a high quality amplifier and condenser supporting its high performance analog circuit (NJM5532 OPAMP: for ADC,DAC,Line in and out and NJM2068 OPAMP: for Phono )
    • High End Audio Grade Connections: The GT40α is equipped with gold-plated Teflon-insulated RCA jacks with an extremely high quality aluminum chassis and machined volume knob


GT40α USB DAC Specifications

    • USB & Analog Playback and Record multimedia audio system
    • Connectivity: USB B Interface, Analog input/output RCA jack
    • USB Playback Resolution : 24bits/192kHz (Max)
    • USB Recording Resolution: 24bits/192kHz (Max) supports 44.1 /48 /88.2 /96 /176.4 /192 (kHz)
    • Frequency response: 20Hz ~ 20kHz (+/-0.5 dB)
    • SN ratio: >90dB (A-wtd) / Line Output
    • Line Output Level: 5 Vrms
    • Line Input Level: MC 0.4mV / MM 4.0mV / Line 2Vrms
    • Headphone Output Level: 1% THD 1kHz (Max.)
      94mW(16 ohm),110mW(32 ohm), 98.6mW (56 ohm), 23mW (300 ohm)
    • Power Supply AC Adaptor Rating: Erp step2 compliant, 2Wire AC Input Type, Class II, AC/DC Switching Adaptor output DC 15V / 0.8A / 12W
    • Dimensions: 150 (W) x 111 (D) x 57 (H) mm 
    • Weight: 650g Approx.
    • GT40a Windows driver supports Win XP, Win 7 and Win 8 (not Win Vista)

The load (Input Impedance) for the ADL GT40α is fixed at 47K ohm for MM and 100 ohm for MC

Input Sensitivity Level for MM: 4.0mVrms at 1K Hz
Input Sensitivity Level for MC: 0.4mVrms at 1K Hz
Input Sensitivity Level for LINE: 400mVrms at 1K Hz
Maximum Input Level for LINE: 2Vrms at 1K Hz
MC input to LINE output (Vol./Max.) => 70dB @ 1K Hz ,( +/-1dB)
MM input to LINE output (Vol./Max.) => 50dB @ 1K Hz ,( +/-1dB)
LINE input to LINE output (Vol./Max.) => 8dB @ 1K Hz ,( +/-1dB)

GT40α has no setting for gain to match different impedance headphones.
We recommend using 16 ohm to 300 ohm impedance headphones. 


Brand ADL
Shipping Weight 0.8000kg
Shipping Width 0.240m
Shipping Height 0.100m
Shipping Length 0.180m

1 Year Warranty

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