dbx 540 Tube Mic Preamp with Optical Compressor

537.00 (including VAT @ 23%)

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Item available to order

This item is available to order, and we do not currently have the item in stock.

When you place your order, we will request the item from our supplier as soon as possible. We will dispatch this product to you as soon as it is received from our supplier.

"Estimated delivery to you" is our estimate of when we will be able to deliver the product to you, based on our supplier's normal delivery timescales. If we become aware it is going to take significantly longer than normal to deliver this item, we will let you know, otherwise, we will advise by email or text message when the item has been dispatched from our distribution centre.

Estimated delivery to you: 11th April 2017
FREE Delivery available.

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30 day money back guarantee included

30 day money back guarantee included

Once the product is delivered, you have 30 days to decide that you definitely want to keep it. If you decide it is not suitable for any reason, you can return it back to us for replacement or full refund, including standard delivery charges.

All Products are new unless stated, and include a minimum of one year warranty.

Some items are only eligible for money back guarantee if they are returned to us unused and sealed in the original packaging, and in the case of software, unregistered. These items include:

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Optional: 5 year warranty: €34.90
(Includes 90 day money back guarantee)


The product price includes a one year warranty and 30 day money back guarantee.

However, the Gear4music extended warranty scheme provides an enhanced service, and is designed to offer a higher level of protection than many 'free' warranties offered by some retailers and manufacturers.

The highlights of this enhanced warranty service are:

  • Warranty is extended to 5 years from the date of delivery.
  • Our Money Back guarantee is extended from 30 days to 90 days (terms apply after 30 days)
  • Collection and delivery costs are included for the first two years
  • Claim 50% cash back on the cost of the policy after 5 years if it has not been used!
  • Warranty is transferable if the item is re-sold
  • Loan or replacement equipment will be provided if the product isn't repaired within 30 days
  • If an item can not be repaired, a similar alternative product or cash discount (as defined in this policy) will be offered
  • The policy can be cancelled within 30 days, and at any time after that for a pro-rata discount

Please note that this extended warranty is currently only available on products sold within the EU or EEA, and is subject to the terms and conditions as detailed on the extended warranty certificate provided.

For customers in outlying areas of the country, the price of the Extended Warranty may be marginally higher, due to the potential for higher collection and redelivery transport costs.

This enhanced warranty is in addition to the standard Gear4music and manufacturer warranty policies, and the Gear4music terms and conditions of trade. No statement or condition of sale contained within these terms affects or restricts your statutory rights as defined under the Consumer Contracts Regulation 2014.

Product Ref: 68562

  • Suitable for all dbx 500-Series Systems
  • Onboard Dual-Function VU Meter
  • Inputs Gain Control and Output Volume Control
  • Switchable Phantom Power and Phase Invert
  • Guarantees Pristine Audio Output

dbx 540 Tube Mic Preamp with Optical Compressor


The dbx 540 Tube Mic Preamp is a single-slot 500-series microphone preamp that boasts pristine audio output and a superior-quality design. The dbx 540 features an interchangeable 12AX7 preamp tube that is perfect for experimenting with a variety of both modern and vintage tubes until the 540 delivers the sound and performance you desire. The dbx 540 is also equipped with a super-fast in-line optical compressor, responsive hand-machined controls and LME49720 low distortion/low noise Op Amps; Push and shape the tone of any microphone with the full-featured dbx 540 Tube Mic Preamp.

Product Ref: 68562

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Full Description

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  • Suitable for use in all 500-series-compatible systems
  • 12AX7 electron tube
  • Class A transformerless 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


  • Mic/Line Inputs: TRS Balanced
  • Impedance: 3k Ohms
  • Mic Input Gain: 10db - 60dB
  • Phase Reversal: Switchable
  • Phantom Power: +48V, Switchable
  • Instrument Input: 1/4'' Jack Unbalanced (Or XLR from Rear Panel
  • Instrument Input Gain: 0dB - 45dB
  • Outputs: XLR + 1/4'' Jack
  • Line Input Frequency Response: 10Hz - 40kHz within 1dB
  • Mic Input Frequency Response: 10Hz - 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
Your order may be delivered with a plug adapter
If any electrical items in your order are supplied with a United Kingdom plug connection, a suitable plug conversion adapter will be included free of charge.