Balanced headphone amplifier and DAC

The D&A Alpha is a compact desktop DAC and headphone amplifier built for clean conversion, serious output power, and flexible day-to-day connectivity. Run it from USB, optical, coaxial, or Bluetooth, and then drive headphones from 4.4mm balanced or 6.35mm single-ended, or feed powered speakers and amps from XLR or RCA line out. Under the hood, the Alpha focuses on noise control and stability, pairing careful PCB layout with a dual-module power system and discrete regulation.

Dual ESS decoding

The Alpha’s decoding stage is built around dual ESS ES9039Q2M DAC chips configured in a true balanced architecture, with each channel handled independently to reduce crosstalk and preserve channel separation. This dual-DAC layout feeds a multi-channel summation stage designed to lower noise and improve linearity before the signal reaches the analog section. On the digital side, USB decoding supports up to 768kHz/32-bit PCM and native DSD512, while optical and coaxial inputs support up to 192kHz/24-bit and DoP64. 

Engineered signal integrity

The Alpha uses a four-layer PCB that routes critical signals on protected inner layers, with grounded outer layers helping shield interference. The layout separates digital control, high-speed data, analog audio, and power into distinct domains (with independent ground planes and star power routing) to reduce noise transfer between sections. For timing-critical paths, ±5ps delay control improves phase matching across four differential pairs.

Discrete power delivery

Power is handled by dual independent Mean Well modules—one dedicated to the DAC section and one to the headphone amp section—followed by purification and discrete component regulation. This keeps rails stable under load so dynamics stay intact when you switch from sensitive IEMs to harder-to-drive headphones.

Parts that support consistency

Precision capacitor selection is treated as part of the tuning process, with testing by position to finalize the production formula. The circuit also uses high-precision low-TCR resistors (+1% tolerance, +25ppm/°C) to help values stay stable when the chassis warms up during long listening sessions.

Bluetooth that stays out of the way

For wireless listening, the Alpha includes Bluetooth 5.3 with codec support that includes LDAC, aptX, aptX HD, AAC, and SBC. A concealed large-diameter helical antenna is designed to improve effective reception area while keeping the rear panel clean. 

Protection built for real use

The Alpha’s protection suite covers thermal and circuit safeguards, including distributed cooling that keeps temperature swings within ±2°C. DC/overvoltage/overload protection and pop-free relays help protect both the amplifier and whatever you have connected, which is especially useful if you alternate between headphones and line out. The amp independently monitors all 4 output phases.

One box for phone, computer, and speakers

se Bluetooth for mobile playback, USB for a computer-based DAC/amp, and LINE OUT when you want to feed powered monitors or an external amplifier. LINE OUT can also act as a digital preamplifier when you want volume control at the source rather than reaching for a separate control box.

Power and gain that match your headphones

The Alpha provides multiple gain selections to make volume control usable across different headphones. Balanced gain steps are listed as -3.3dB (L), +6dB (M), +12dB (H), with unbalanced gain steps listed as -9.3dB (L), 0dB (M), +6dB (H). Output power scales by load (up to 9000mW ×2 at 32Ω from the balanced output) so you can keep headroom without riding the top of the volume range.

Product highlights

• USB / optical / coaxial / Bluetooth inputs
  
• 4.4mm balanced and 6.35mm single-ended headphone outputs
  
• XLR and RCA line outputs for speakers and amps
  
• Bluetooth 5.3 codec support includes LDAC, aptX, aptX HD, AAC, SBC
  
• Dual independent Mean Well power modules with purification and discrete regulation
  
• Four-layer PCB with separated domains and ±5ps delay control for phase matching
  
• Protection suite with pop-free relays and multi-phase monitoring
  
• MQA decoding via USB / optical / coaxial

Specs

• Inputs: USB / Optical / Coaxial / Bluetooth
  
• Outputs: XLR / RCA / 4.4mm headphones / 6.35mm headphones
  
• Line output voltage (XLR): 5.2Vrms
  
• Line output voltage (RCA): 2.5Vrms
  
• Headphone output level (balanced): 7500mW ×2 (16Ω), 9000mW ×2 (32Ω),
• 2200mW ×2 (150Ω), 1100mW ×2 (300Ω), 550mW ×2 (600Ω)
  
• Headphone output level (unbalanced): 5000mW ×2 (16Ω), 2500mW ×2 (32Ω),
• 500mW ×2 (150Ω), 250mW ×2 (300Ω), 150mW ×2 (600Ω)
  
• THD+N (XLR): 0.00006% (-123.5dB) (UN-WTD)
  
• THD+N (RCA): 0.00007% (-121dB) (UN-WTD)
  
• THD+N (HP): 0.00017% (-115dB) (UN-WTD)
  
• Dynamic range: XLR 131dB, RCA 127dB, HP 125dB
  
• SNR: XLR 131dB, RCA 127dB, HP 125dB
  
• Output impedance: Line out 100Ω, HP out Near 0Ω
  
• Headphone amplifier gain (balanced): -3.3dB (L), +6dB (M), +12dB (H)
  
• Headphone amplifier gain (unbalanced): -9.3dB (L), 0dB (M), +6dB (H)
  
• USB transmission: USB 2.0 (Asynchronous)
  
• USB compatibility: Windows 7/8/8.1/10/11 (Needs driver), macOS, iOS, Linux, Android
  
• MQA decoder: USB / Optical / Coaxial
  
• MQA-CD decoder: Optical / Coaxial
  
• Max supported sampling rate (USB): Up to 768kHz/32bit; DSD512 (Native)
  
• Max supported sampling rate (coaxial): Up to 192kHz/24bit; DoP64
  
• Max supported sampling rate (optical): Up to 192kHz/24bit; DoP64
  
• Bluetooth: 5.3 (Support SBC, AAC, aptX, aptX HD, LDAC)
  
• Power consumption: <50W
  
• Standby power: <0.5W
  
• Size: 7.68 × 2.17 × 8.19 in (195 × 55 × 208 mm) (W × H × D)
  
• Weight: 3.64 lb (1.65 kg)

What’s included

• Alpha ×1
• Power cable ×1
  
• USB cable ×1
  
• User manual ×1