Darkglass Microtubes B7K Bass Preamp Pedal

Written by

Jed Van Wyngaardt

There are plenty of bass drive pedals available but not many have this level of control right from the pedal. Mixing together a high gain overdrive, a powerful preamp and a strong 4 band EQ this is ultimate all in one bass toolbox for getting your sound anywhere, anytime.

The Overdrive

Using the same great circuit that comes in the B3K the B7K has all of the controls you need with Level, Drive, Blend knobs on top of a pair of 3 way switches that change the low and high end saturation. With this alone you get a great range of tones for a mid gain crunch to all out djent distortion.

4 Band EQ

We have all played bass amps with unresponsive EQ sections that just don't give us the sound in our head. We also all have hopefully found a tone we love in our amps, but sometime you want something different at a moments notice. This is why the 4 band EQ on this pedal is so good. With up to +-12dB at 100Hz, 1kHz, 2.8kHz and 5kHz you can really dial in the exact sound you want.

Preamp I/O

The difference between an overdrive and a preamp is that one is designed to go in to an amplifier the other is generally designed to go in to PA speakers. This is both as you have a regular output to run to your amp, a parallel output (not effected) that you can run to a completely separate rig if you want and a DI output (effected) that goes straight to your front of house and stage monitors.

Here's what Darkglass say about the B7K Bass Preamp/Overdrive

The Microtubes B7K takes the powerful dynamic saturation circuit of the B3K and adds a four-band equalizer and a balanced line driver for even greater versatility. Designed for both studio and live use, it will take your direct sound to a whole new level.


Sets the volume of the overdriven signal.

Sets the amount of saturation in the overdriven signal.

Mixes the clean input signal with the overdriven signal. The clean signal remains at unity gain while the volume of the overdriven signal is set by the Level knob, allowing for fine control of the blend ratio.

 Grunt Switch
Sets the amount of low frequency content to saturate by selecting between three different bass boost levels before the clipping stage.

 Attack Switch
Sets the amount of treble content to saturate: The "Boost" setting emphasizes the treble content extra clarity and presence. The "Flat" position leaves this register untouched while the "Cut" position will reduce the amount of high frequencies being saturated.This new addition helps to keep the treble portion of the signal under control, specially useful when playing with new strings and/or cabinets with tweeters!

+-12dB @ 100Hz

Low Mids
+-12dB @ 1kHz

Hi Mids
+-12dB @ 2.8kHz

+-12dB @ 5kHz

Parallel Output
A passthrough for your input signal, useful for parallel processing.

Direct Output
A balanced version of the 1/4" output, useful for running into PA's or studio mixing consoles.

12×10.7 cm (4.72×4.21 in)

The Microtubes B7K has a current draw of 30mA. Only use a regulated 9V DC adapter with a center-negative plug. Due to ecological reasons it does not accept batteries. Unregulated power supplies and/or higher voltages may result in suboptimal noise performance and even damage your unit, voiding the warranty.



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