DBX 540

The dbx 540 is a single-slot 500-series tube microphone preamp that boasts pristine audio output, superior-quality high-end design at a value price. 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 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.

Push and shape the tone of any microphone with the full-featured dbx 540!

Highlights

• Suitable for use in all 500-series-compatible systems
• 12AX7 electron tube
• Class A transformless high voltage signal path
• Adjustable optical compressor
• Switchable phantom power
• Switchable phase invert
• Switchable -20dB pad
• Dual-function VU meter: master volume / gain reduction
• Input gain control
• Output volume control

Technical 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