Wolff Audio RefPre

Wolff Audio RefPre 500 Series – a transformerless microphone preamplifier in 500 Series format, designed for critical recording and sampling applications demanding absolute transparency.

The RefPre is a precision instrument that captures sound without any coloration, preserving complete fidelity to the source. Thanks to its minimalist transformerless architecture and carefully optimized signal path, the preamp delivers exceptionally clean sound with extremely low self-noise (-125 dBu EIN) and distortion as low as 0.0005% at 60 dB of gain. The unit features stepped gain control from -10 dB to +60 dB in 10 dB increments, plus an additional ±6 dB trim control for precise calibration.

A unique feature is the dedicated ribbon microphone mode, which automatically adjusts impedance, adds 10 dB of gain (total 70 dB), and locks out phantom power to protect delicate ribbon transducers. The continuously adjustable output fader enables precise signal level control, while the switchable 80 Hz high-pass filter (12 dB/octave) eliminates unwanted low-frequency rumble. The RefPre is an ideal choice for working with reference microphones (Earthworks, Neumann) and emulation systems (Slate VMS).

KEY FEATURES

• Transparency: Transformerless path, 0.0005% distortion, -125 dBu EIN noise floor.
• Precise Control: Stepped gain -10 to +60 dB (10 dB steps) + ±6 dB trim.
• Ribbon Mode: Additional 10 dB gain (total 70 dB), auto impedance matching, phantom lockout.
• Frequency Response: ±0.5 dB from 10 Hz to 80 kHz – full-spectrum precision.
• High Headroom: +28 dBu – handles high-output microphones without distortion.
• Instrument Input: Dedicated Hi-Z preamp on front panel (for guitars and basses).
• Signal Monitoring: LED indicator (green on signal, flashing red at +18 dBu).
• Connectivity: XLR inputs (front and rear), polarity reverse, 48V phantom with safety lockout.

TECHNICAL SPECIFICATIONS

• Format: 500 Series
• Type: Microphone/Instrument Preamp (Transformerless)
• Gain: -10 dB to +60 dB (stepped), +70 dB in Ribbon mode
• Trim: ±6 dB
• Equivalent Input Noise (EIN): -125 dBu
• THD Distortion: 0.0005% at 60 dB gain
• Frequency Response: 10 Hz – 80 kHz (±0.5 dB)
• Headroom: +28 dBu
• Filter: 80 Hz High-Pass (12 dB/octave, switchable)
• Inputs: XLR (front and rear), Hi-Z Instrument (1/4" jack)
• Phantom Power: 48V with lockout in Ribbon mode