Wolff Audio RefPre 500-Series Reference Microphone Preamplifier

The Wolff Audio RefPre is a 500-series reference microphone preamplifier built around one governing principle: complete transparency. Its transformerless circuit and minimal signal path are engineered to pass the source signal through without coloration, making it an ideal front end for sampling and emulation microphones, high-output condensers, and ribbons alike. The RefPre offers 60dB of stepped gain, a dedicated ribbon mode that extends gain to 70dB with automatic impedance adjustment and phantom power lockout, and relay-based switching throughout for long-term reliability. Providence Sound And Vision carries the Wolff Audio RefPre in Los Angeles for recording engineers, producers, and broadcast professionals who need to hear the microphone — not the preamplifier.

Key Features

• Transparent Transformerless Design — Minimal circuitry and a short signal path preserve the character of the source without adding color, delivering –125dBu EIN and 0.0005% THD at 60dB of gain.
• Stepped Gain Control — A rotary switch provides repeatable gain adjustment from –10dB to 60dB in 10dB steps, with a ±6dB continuous trim for fine-tuning.
• Ribbon Mic Mode — A dedicated ribbon circuit adds 10dB of gain (70dB total), automatically adjusts input impedance, and engages a phantom power lockout to protect ribbon elements.
• High Headroom — +28dBu maximum output with a frequency response of ±0.5dB from 10Hz to 80kHz, accommodating virtually any mic or source type.
• Output Fader — Continuous adjustment from –∞ to full output for precise level control into the rack.
• Switchable 80Hz High-Pass Filter — A 12dB/octave filter clears low-frequency buildup without affecting midrange or high-frequency detail.
• Signal Indicator LED — Glows green on signal presence and flashes red at +18dBu, 10dB below clipping, for at-a-glance level monitoring.
• Flexible Input Routing — Mic input accessible from both front and rear panels; a dedicated front-panel Hi-Z instrument input selected via the Mic/Inst switch.
• Relay-Based Switching — All gain steps and switches are relay-controlled for improved reliability and noise-free operation.
• Output Muting on Switching — Output mutes automatically during polarity reverse and 48V phantom power switching to protect downstream gear.

Specifications

• Format: 500-series module
• Gain Range: –10dB to 60dB (stepped, 10dB increments); 70dB in Ribbon mode
• Gain Trim: ±6dB continuous
• Output Fader: –∞ to full output, continuous
• EIN: –125dBu
• THD: 0.0005% @ 60dB gain
• Maximum Output: +28dBu
• Frequency Response: ±0.5dB, 10Hz – 80kHz
• High-Pass Filter: 80Hz, 12dB/octave, switchable
• Phantom Power: 48V (output mutes during switching)
• Polarity Reverse: Yes (output mutes during switching)
• Input: XLR mic (front and rear panel); Hi-Z instrument (front panel)
• Switching: Relay-based throughout
• Shipping Weight: 2 lbs
• Condition: Open Box

Preowned at Providence Sound And Vision

This Wolff Audio RefPre is open box, fully inspected and verified by Providence Sound And Vision before reaching the shelf. It carries the same 7-day risk-free return policy and lifetime support that Providence Sound And Vision extends on every piece of gear it sells.