The QDA-428 A is a fully digital 4-channel Class-D high-power amplifier designed for professional audio applications such as fixed installations, passive PA systems, and multi-channel setups. With over 90% efficiency, extensive DSP capabilities, and versatile input/output options, it’s an ideal tool for demanding sound reinforcement tasks.

Each of the four independent channels is equipped with full DSP processing including 6-band parametric EQs, crossover filters, delay, dynamic processing, subsonic filters, phase inversion, and limiters. The user interface features a 5-button navigation pad and four rotary encoders with push function. An LCD display and RGB LEDs provide clear feedback on system and signal status.

The amplifier supports 4 analog and 2 digital inputs (AES/EBU and S/PDIF) and allows for combined use. It includes an SD card slot for storing presets and a modular slot for future network audio or control interfaces. Digital outputs are available via AES/EBU.

Its power supply is optimized for audio performance with PFC support and includes extensive protection circuits. The rugged housing makes it suitable for continuous operation in professional environments.

Technical Specifications:

• Model: QDA-428 A
• Amplifier Type: Class-D, 4-channel, digital
• Output Power (1 kHz, 1% THD):
• 4× 400 W @ 8 Ohm
• 4× 700 W @ 4 Ohm
• Output Impedance: 4–8 Ohm
• Inputs:
• 4× analog line
• 2× digital (AES/EBU, S/PDIF, 16–24 Bit / 32–192 kHz)
• Digital Output: AES/EBU 24 Bit / 48 kHz
• Audio DSP:
• 6-band parametric EQ per channel
• Crossover, Delay (0–1000 ms), Peak-RMS Limiter, Compressor
• Phase inversion (180°), Subsonic filter, Matrix routing, Mute, Gain
• Control Interface: 5-button navigation pad, 4 push-rotary encoders
• Display: Graphic LCD + 4 RGB status LEDs
• Presets: Factory and user presets; SD card slot included
• Expansion Slot: For future audio/control network integration
• Interfaces: RS-232, NC contact
• Frequency Response: 20–20,000 Hz (–3 dB)
• THD: < 0.5 % at 1 kHz
• SNR: > 100 dB
• Input Sensitivity: 0 dB (775 mV), adjustable
• Power Consumption: Max. 2500 W
• Current Consumption @ 230 V:
• 1/8 load: 1.49 A
• Full load: 10.8 A
• Power Supply: 90–250 V AC, 50–60 Hz, PowerCon In
• Housing: 48,3 cm ( 19 inch ), 2U rack mount
• Dimensions (W×H×D): 483 × 88 × 375 mm
• Weight: 8.5 kg

Scope of Delivery:

• 1× QDA-428 A amplifier
• PowerCon mains cable
• User manual

Key Features:

• 4 fully independent DSP channels with advanced audio processing
• Flexible input/output configuration (analog and digital)
• Future-ready with modular expansion slot
• Rugged build for professional installations
• User-friendly operation via onboard controls