The Gainlab Audio Auditor 500 is a professional Class-A headphone amplifier in a single-slot 500-series format. Designed for critical studio, broadcast and mobile monitoring, it delivers high output power, low distortion, full-range response, Mono and Mute functions, Line Through connectivity and comprehensive protection for headphones and connected equipment.
 
The Gainlab Audio Auditor 500 is a purpose-built headphone amplifier for engineers who want a serious monitoring stage inside a 500-series rack. Unlike a basic utility headphone output, Auditor uses a pure Class-A amplifier design to provide high current capability, low distortion and a controlled, transparent signal path for critical listening with both low- and high-impedance headphones.
Designed as a single-slot 500-series module, Auditor integrates naturally into tracking racks, portable recording systems, broadcast setups, mix rooms and mastering environments. It receives its balanced line-level input through the host chassis backplane and provides a front-panel headphone output alongside a Line Through output for passing the incoming signal to another 500-series module or external destination.
 
With up to 1 W of output power per channel, Auditor has the drive required for demanding headphones, including lower-impedance professional models that benefit from high current delivery and higher-impedance designs that require substantial voltage swing. The result is a stable and detailed headphone monitoring path with strong dynamic range, controlled bass performance and sufficient headroom for accurate session work.
 
Auditor includes practical monitoring tools for professional use. The Mono function makes it easy to check mono compatibility, assess balance decisions and identify phase-related problems without changing DAW routing. The Mute function provides instant silence for safe headphone changes, communication during tracking or quick monitoring control in busy recording sessions.
 
Gainlab has also included comprehensive output protection. Safeguards against DC offset, overcurrent and power-on transients help protect connected headphones from potentially damaging events. This matters particularly in shared studio facilities, mobile rigs and production environments where headphones may be frequently connected, disconnected or swapped between performers and engineers.
 
The front panel provides visual indication of incoming line level and headphone output level, supporting practical gain staging and helping users avoid unexpected overload. Its accurate, wide-bandwidth Class-A circuit is designed to maintain a linear response across the audible spectrum and beyond, making Auditor suitable for reference monitoring, editing, mixing, mastering, broadcast and high-resolution playback.
 
Gainlab Audio Auditor 500 is ideal for studios that want to add a dependable, high-quality headphone amplifier to an existing 500-series system. It can serve as a dedicated engineer headphone output, an artist-monitoring feed, a compact control-room reference stage or a high-performance headphone solution for a portable production rack.
 
Important note: Auditor is a 500-series module only. A compatible powered 500-series chassis is required and is not included.
 
Key features
 
Professional Class-A headphone amplifier in 500-series format
Single-slot 500-series module
Up to 1 W of output power per channel
Designed for low- and high-impedance headphones
Low distortion and wide-bandwidth performance
Balanced line-level input through the 500-series chassis backplane
Front-panel headphone output
Line Through output for signal pass-through
Mono function for mono compatibility and phase checks
Mute function for instant headphone silence
Line-level and headphone output-level indicators
DC offset, overcurrent and power-on transient protection
Suitable for studio, broadcast, mastering, editing and field recording
Transparent monitoring path for critical headphone listening
Requires a compatible powered 500-series rack chassis
Applications
Dedicated engineer headphone monitoring
Performer headphone feed in a tracking rack
Critical headphone reference for mixing and mastering
Portable 500-series recording and broadcast systems
Mono compatibility and phase checking
High-power monitoring for demanding headphones
Line-level signal pass-through to other 500-series modules
Editing, restoration, post-production and broadcast work
Secondary headphone monitoring in hybrid studio setups