AEA RPQ503 500 Series Mic Preamp & EQ

The AEA RPQ503 is the next evolution in AEA’s renowned line of high-impedance, high-gain preamplifiers, bringing the celebrated sound of the RPQ3 to the 500 Series format. Featuring ultra-low-noise, low-distortion op-amps, an ultra-high 68 kΩ input impedance, and up to 85 dB of clean gain, the RPQ503 delivers unmatched clarity and detail—perfect for ribbon, condenser, and dynamic microphones alike. Beyond its exceptional preamp stage, the RPQ503 includes an expanded EQ section with sweepable low- and high-frequency bands, offering up to ±20 dB of boost or cut on intuitive, dual-concentric controls. Open and transparent yet responsive and dynamic, the RPQ503 is a versatile front-end solution for any signal path.

Key Features

• 1-space 500 Series preamp with AEA’s 3rd-generation preamp circuitry.
• Ultra-high 68 kΩ input impedance (phantom power off) for optimal ribbon mic performance.
• Gain range from 7 to 85 dB for detailed, noise-free amplification.
• Expanded EQ section with LF/HF sweepable frequencies.
• Up to ±20 dB boost/cut for both low and high bands.
• EQ in/out switching with center detents on gain pots for quick bypass of individual bands.
• +48V phantom power, polarity reverse, and mic/line input switching.
• Made in the USA by AEA Ribbon Mics Inc. (est. 1964).

Specifications

• Max Gain: 85 dB
• EIN: -130 dBu typical (40 Ω source, unweighted), -128 dBu typical (150 Ω source, unweighted)
• Frequency Response:
  • 30 dB gain: -0.6 dB @ 10 Hz, -3 dB @ 160 kHz
  • 85 dB gain: -3 dB @ 10 Hz and 160 kHz
• THD+N: 0.0018% (1 kHz, 22 Hz–22 kHz, 30 dB gain, +4 dBu output)
• Max Output Level: +27 dBu into 600 Ω load
• Input Impedance: 68 kΩ (phantom off), 11.3 kΩ (phantom on)
• Output Impedance: 50 Ω
• Max Input Level: +20 dBu (minimum gain)
• Mic Gain Control: 12-position switch, +7 dB to +65 dB
• Output Trim: Continuously variable, 0 to +20 dB
• EQ Type: First-order shelving, ±20 dB boost/cut
• LF Sweep: 40 Hz–675 Hz
• HF Sweep: 2 kHz–28 kHz
• LED Meters: Green (-20 dBu), Yellow (0 dBu), Red (+20 dBu, clip at +27 dBu)
• Dimensions: 1.5” W × 6.8” D × 5.2” H (3.8 × 17.27 × 13.34 cm)
• Weight: 12 oz (0.338 kg)

With its transparent gain, ribbon mic–friendly impedance, and musical EQ shaping, the AEA RPQ503 delivers exceptional sonic quality and flexibility, making it an indispensable addition to any 500 Series rack.