Crazy Tube Circuits Unobtanium

Klon Centaur overdrives and Dumble amps are among the rarest pieces of guitar gear out there, and therefore also the most cloned. The Crazy Tube Circuits Unobtanium gives you both sonic flavors in a dual, stackable overdrive – with an extra voicing for the Dumble side and plenty of tweakability.

The right side of the circuit (which is the first in line) sports a faithful reproduction of the Klon, based on a germanium diodes-based design that delivers a wide palette of tones ranging from transparent boost to high headroom overdrive, a Volume knob with plenty of gain on tap, and a Treble control that can boost or cut the high end.

A voice toggle switch on the right provides two different voices: the stock clipping/compression or a modified one that enhances gain and headroom/output as you turn the gain knob clockwise.

Another toggle switch on the left lets you select true bypass or an original buffer bypass, which adds add clarity and works better for those who run long cables.

The left sideĀ is the Dumble side, aka D-Style overdrive. There are two main version of the Dumble amps, the Super Overdrive and the Steel String Singer – the Unobtanium provides both emulations at the flick of theĀ voice toggle. The former delivers a celebrated mid to high gain overdriven sound full of sweet overtones, while the latter shines for clean and glassy tones with natural and transparent compression.

The design here reinterprets and streamlines the original’s controls through an Emphasis knob that affects the presence and the low end of the signal before it hits the drive stage, and a Tone control that sets the amount of post-overdrive high-end.

An external footswitch can select amp voicing on the Dumble side, while a couple of internal trimmers allow to fine-tune the EQ and volume boost of D-style overdrive.

Hear how it sounds in the videos below.

Crazy Tube Circuits Unobtanium, Builder’s Notes

Introducing the Unobtanium, a rare sonic element born out of legendary tones!

A mythical overdrive meets the tone and feel of two iconic amplifiers. We have accurately recreated the circuit of the high headroom overdrive with the magic blend of clean and overdriven tones and added extra features for versatility. The amp-in-a-box section uses an all-analog circuit to capture the essence of two legendary D-style tube amplifiers. From tube-like compressed fat clean to sweet singing overdrive with blooming harmonic overtones. Combine both sides for near infinite smooth sustain and enter sonic bliss while a passive series effects loop gives you the option to connect your beloved pedals between the overdrive and amp section, building your ideal rig.


  • Right side: faithful reproduction of the mythical overdrive circuit including the fabled germanium diodes
  • Wide gain range control: from transparent boost to high headroom overdrive
  • Treble control is an active circuit to boost or cut treble
  • Volume knob sets overall output. Huge amount of dB boost available
  • Toggle switch to select between the original buffer bypass to add clarity and run long cables or true bypass
  • Toggle switch to select between stock clipping / compression or enhanced gain and headroom/output as you turn gain knob clockwise
  • Left side: D-style amp in a box overdrive
  • Gain control: from clean boost to sweet singing overdrive
  • Emphasis control is a pre-drive EQ to control presence and bottom end response
  • Tone knob controls the amount of post overdrive high end frequencies
  • Volume knob sets overall output. Match bypassed volume or use as a clean boost or preamp
  • Toggle switch selects between 2 distinct D-style overdrive circuits
  • SSS: clean and transparent overdrive with natural organic compression
  • ODS: higher gain overdrive with enhanced mid frequencies and harmonic overtones
  • External footswitch input to select amplifier voicing (bypasses on board toggle switch)
  • Internal trimmers adjust EQ and volume boost of D-style overdrive voicings
  • Passive series effects loop to connect other pedals between the two sections or use them separately as independent effects
  • Runs internally at 18V DC for higher headroom and tube-like performance
  • Top mounted jacks
  • Click-less True Bypass design via high quality relays