AEA RPQ503 is a single-slot 500 Series microphone preamplifier built on the third-generation circuit of the flagship RPQ3. Its combination of ultra-low-noise op-amps, 68 kΩ input impedance, and up to 85 dB of clean gain makes it a modular front-end optimized for passive ribbon microphones — while performing equally well with dynamic and condenser mics.
85 dB of Clean Gain for Passive Ribbons
Passive ribbon microphones are the hardest load for a preamp: low output level, low coil impedance, and sensitivity to in-circuit noise. The RPQ503 addresses this with a 68 kΩ input impedance (phantom off), allowing the ribbon to operate without high-frequency loading losses. Self-noise of –130 dBu typical into a 40 Ω source keeps the noise floor below audibility even in quiet acoustical environments. The twelve-position gain switch (+7 to +65 dB) combined with an output trim (0 to +20 dB) delivers a total range of 7–85 dB with repeatable, session-to-session consistency. A multi-color LED meter on the module face displays signal level and clip status at a glance.
CurveShaper EQ — Tone Shaping at the Source
The built-in CurveShaper EQ section offers ±20 dB of boost or cut across independently sweepable LF and HF bands. For ribbon microphones with a natural high-frequency rolloff, correcting at the preamp stage — before the signal passes through converters and plugins — means less gain applied later and a lower cumulative noise contribution from the chain. Controls use dual-concentric potentiometers: the outer ring sets the shelf frequency, the inner knob adjusts the amount. The EQ engages via a dedicated switch with a center detent at unity, enabling fast A/B comparisons between processed and flat responses. A balanced line input bypasses the mic stage entirely for direct line-level processing.
KEY FEATURES
- API 500 Series format, 1 slot
- AEA Gen 3 circuitry (derived from RPQ3)
- Input impedance: 68 kΩ (phantom off) / 11.3 kΩ (phantom on)
- Gain range: 7–85 dB (12-position switch +7 to +65 dB + output trim 0–20 dB)
- Self-noise: –130 dBu typical (40 Ω source), –128 dBu typical (150 Ω source), unweighted
- CurveShaper EQ: LF + HF shelving, ±20 dB, continuously sweepable, separately switchable
- Dual-concentric EQ potentiometers
- +48 V phantom power, polarity reverse, mic/line switch
- Max input level: +20 dBu (minimum gain)
- Max output level: +27 dBu (600 Ω load)
- Multi-color LED level and clip indicator
- Made in the USA
TECHNICAL SPECIFICATIONS
- Format: API 500 Series, 1 slot
- Input impedance: 68 kΩ (phantom off) / 11.3 kΩ (phantom on)
- Gain range: 7 dB – 85 dB
- Self-noise: –130 dBu typical (40 Ω) / –128 dBu typical (150 Ω), unweighted
- EQ: 2-band shelving, ±20 dB, continuously sweepable LF and HF
- Max input level: +20 dBu
- Max output level: +27 dBu (600 Ω)
- Phantom power: +48 V (switchable)
- Polarity reverse: yes
- Mic/line switch: yes
- Level indicator: multi-color LED
- Made in: USA
