Darkglass Electronics Microtubes B7K Bass Preamp



Darkglass Electronics

The Microtubes B7K is the meanest beast of the family. It features all the handy features of it's little brother and much more! One of the amazing improvements is the musical four band EQ which rises-up exponentially the amount of tonal capabilities, giving you all the shaping, and texture options you'll ever need. This, combined with the Grunt and Attack toggle switches give you all the versatility preamp in the palm of your hand.

With the B7K you will easily create your own signature sound in a huge range of shades from classic warm tube tones, even to scooped ultra high gain distortion. Other great spec of the B7K is the built in DI Output which makes it perfect for live and studio applications. It works perfectly either used as a stand-alone preamp going to a power amp and/or PA system, or to spice up the tone of your favorite amplifier. The Microtubes B7K is a dream come true to get your own signature sound.

Useful Tips:

  1. With the blend at minimum it can be used as a clean 4 band EQ for shaping your clean sound.
  2. The parallel output is very useful! for example you can get your Microtubes and clean signal at the same time, this comes in handy in studio situations, or if you want to set up a stereo rig, allowing you to run your dirty and clean signal through different amps!


  • Original Design featuring our hybrid FET/CMOS gain stages to provide an amazingly natural tube-like dynamic response
  • Level: Controls the level of the Overdriven Signal
  • Blend: Allows to mix the exact amount of clean signal with the Overdriven.
  • Drive: Sets the amount of preamp Gain.
  • Grunt Switch: Choose between 3 different Bass boost levels before the gain stages, this interacts with the Drive knob, so you can choose how much of bass you want to saturate
  • Attack Switch: This switch features the same “Ultra Hi” option in most tube bass amps. And it allows you to choose how much treble content you want to saturate. The Boost setting gives you more clarity, presence and definition. The Off option will round your sound, making it a bit warmer and less sharp.
  • Low: +-12dB @ 100Hz
  • Mid: +-12dB @ 1kHz
  • Hi Mid: +-12dB @ 2.8kHz
  • Treble: +-12dB @ 5kHz
  • Parallel Output: It allows you to take your clean signal, and re-route to process it in any way you like!
  • DI Output: Perfect for live aplications for going straight to PA System. And also for studio situations going straight to any interface.
  • Gnd Lift/Phantom: Allows you to lift the ground on the DI section for avoiding hums, and any other ground related noise.
  • It can be powered either using a 9V Battery or regulated 9V power supply (center negative). You can also experiment with 12V power supply for extra headroom. Or via the XLR jack with the Phantom Power option.



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