540

Tube Microphone Preamplifier With Optical Compressor, 500 Series

The dbx 540 is a single-slot 500-series tube microphone preamp that boasts quality audio output. 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.

The 540 features 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. The dbx 540’s audio circuit uses LME49720 ultra-low distortion/low noise Op Amps, for superb audio output.

dbx 540 Features:
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 -20 dB pad
Dual-function VU meter: master volume / gainreduction
Input gain control
Output volume control
dbx 540 Specifications:
Mic/Line Input Connectors: TRS balanced
Impedance: 3 k Ohms
Mic Input Gain: 10 dB to 60 dB
Phase Reversal: Switchable
Phantom Power: + 48 V, switchable
Instrument Input Connector: 1/4" jack unbalanced (orXLR from back panel)
Instrument Input Gain: 0 dB to 45 dB
Output Connectors: XLR and 1/4" jack (back panel)
Line in Frequency Response: 10 Hz to 40 kHz within 1dB
Mic in Frequency Response: 10 Hz to 40 kHz within 2.5dB
Compressor Ratio: 1 : 1 - 10 : 1
Compressor Attack: 1 ms - 100 ms
Compressor Release: 0.1 s - 3 s
Shelving filter: 80 Hz
Slope: 16 dB
VU meter: -20 dBu - + 3 dBu
THD: 0.05 % (unweighted)
Signal to Noise: > 101 dB
Power Supply: 500 Series Power Supply Required