Blue Robbie Microphone Preamplifier

Class-A Tube Microphone and Instrument Preamplifier

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The Blue Robbie Class-A Mic Preamp:

Simplicity of design. Purity of sound. Robbie is Blue's Class-A discrete tube microphone and instrument preamplifier. All of the technical quality and design innovation that goes into our line of award-winning microphones has been engineered into making Robbie the finest tube preamp available today. With no ICs and only the highest-quality discrete components from input to output, Robbie is one of the quietest (-131 dB EIN @ 50 ohms) and most detailed (THD 0.006%) tube preamps available today.

It features audiophile-grade ultra low noise metal film resistors and polystyrene capacitors, and provides the user with the best of both worlds: an electronically-balanced, fully discrete input stage, tube gain stage (ECC88 twin triode), and an electronically-balanced solid-state output stage. There is no switching crossover distortion anywhere in the completely balanced audio signal path. And if that's not enough, Robbie achieves and amazing 34dB headroom before clipping! Designed from the ground up, this limited production mic pre is like nothing else commercially available today.

Product Features:

  • Class-A Tube Mic Preamp
  • Made from the highest quality, discrete components available
  • Audiophile-grade ultra low noise metal film resistors
  • Polystyrene capacitors
  • 34dB headroom before clipping
  • Also found as: robbiethepreamp, robbie the mic pre, robbie,
  • Authorized Internet Dealer
  • 1-year Manufacturer's Warranty


  • Minimum Gain: 8dB
  • Maximum Gain: 68dB
  • Frequency Response (+ / - 2 dB ): 10Hz - 100kHz
  • Noise @ 60 dB gain (10 Hz – 30 kHz, 50½ source): -131dB EIN
  • Noise @ 60 dB gain (10 Hz – 30 kHz, 150½ source): -129 EIN
  • THD + Noise @ 60 dB gain (10 Hz – 20 kHz, +22 dBu output): <0.006%
  • Phase Response @ 60dB gain (50 Hz – 20 kHz, +22 dBu output): <5°
  • Common Mode Rejection Ratio (50 Hz – 20 kHz, 100 mV input): 60dB gain > 64dB; 30dB gain > 75dB
  • Maximum Input Level (8 dB Gain, 20 Hz - 20 kHz): +22dBu w/o pad
  • Maximum Output Level (20 Hz – 40 kHz @ 10 k½): +34dBu
  • Mic Input Impedance (20Hz - 20kHz): 5 k ohms (2 x 2,500 ohms)
  • Hi-Z Input Impedance: 1 M ohms
  • Output Impedance: 50 ohms (2 x 25 ohms)
  • Phantom Power: +48VDC, ± 1.5VDC
  • Power Consumption: 8W
  • Power Requirements: 115/230VAC, 50/60Hz
  • Dimensions: 8-1/2"W x 8-1/4"D x 5-1/4"H
  • Weight: 7 lbs.

Preamplifier Specifications

Number of Channels
This is the number of channels the preamp is designed for.
Preamp Type
This defines the type of preamp.
Phantom Power
This specifies whether or not the mic preamp has a phantom power supply.
Frequency Response
The range of frequencies the speaker will reproduce (lowest frequency to the highest). Bigger is better, meaning the wider the range, the better. The optimal range is 20 - 20,000 Hz (which is the range of human hearing).
Gain Range
This is the range of gain for the preamplifier.
THD (Total Harmonic Distortion)
The amount of change in harmonic content of the signal as it is amplified. A lower figure indicates less change and a more accurate amp. THD below 0.10% is inaudible.
Built-in Equalizer
Some preamps have a built-in equalizer to help process the audio. If the preamp has a equalizer, the type of EQ will be listed here.
Phase Invert
If the preamp has a phase invert, it will be listed here.


These are the input connections that go into the preamp.
These are the output connections that go out from the preamp.
Headphone Out
This is the type of connection that the preamplifier uses for a headphone output.
Dedicated Mic Input
This is the type of connection that is used as a dedicated microphone input for the preamplifier.

General Specifications

Rackmount Spaces
This is the total number of spaces that the preamplifier will occupy when mounted on a rack.
The height of the item, measured from top to bottom, in inches.
The width of the item from left to right (side-to-side) measured in inches.
The front-to-rear depth of the item, in inches. If the item is angled or slanted, this value is the bottom measurement.
Weight (Pounds)
This is the weight of the item in pounds (lbs).

Specials with this Item

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Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

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Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: Blue Robbie Microphone Preamplifier

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Blue Robbie Microphone Preamplifier

Class-A Tube Microphone and Instrument Preamplifier


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