dbx 540 Tube Mic Preamp with Optical Compressor

The dbx 540 features a Class A tube preamplifier, switchable phantom power, phase invert, selectable -20dB pad, and a super fast in-line optical compressor. The front panel includes a TRS microphone input - a standout feature typically not found on 500-series preamps.

The easy-access interchangeable 12AX7 preamp tube allows you to experiment with a variety modern and vintage tubes to customize the 540’s sound and performance to your taste. The switchable (in/out) compressor provides adjustable attack and release, and when it’s in use, the on-board VU meter automatically changes from displaying master level to amount of gain reduction, so you can view the exact results of the compression being applied. Editing is done using our smooth, responsive hand-machined controls. And last but not least: The dbx 540’s audio circuit uses LME49720 ultra-low distortion/low noise Op Amps, for superb audio output.

Specifications

• Mic/Line Input Connectors: TRS balanced
• Impedance: 3k Ohms
• Mic Input Gain: 10dB to 60dB
• Phase Reversal: Switchable
• Phantom Power: +48V, switchable
• Instrument Input Connector: 1/4” jack unbalanced (or XLR from back panel)
• Instrument Input Gain: 0dB to 45dB
• Output Connectors: XLR & 1/4" jack (back panel)
• Line in Frequency Response: 10Hz to 40kHz within 1dB
• Mic in Frequency Response: 10Hz to 40kHz within 2.5dB
• Compressor Ratio: 1:1 - 10:1
• Compressor Attack: 1ms - 100ms
• Compressor Release: 0.1s - 3s
• Shelving filter: 80Hz
• Slope: 16dB
• VU meter: -20dBu - +3dBu
• THD: 0.05% (unweighted)
• Signal to Noise: >101dB
• Power Supply: 500 Series power supply required