“We have tried many germanium transistor types and found that the OC45 transistors added a supernatural feel”: Crazy Tube Circuits cooks up a tasty Dumble/Klon stew with the Unobtanium Raw

Crazy Tube Circuits Unobtanium RAW
(Image credit: Crazy Tube Circuits)

Crazy Tube Circuits has released a limited edition twist on its Unobtanium preamp/overdrive pedal, the amp-in-a-box drive twofer that has a Klon-style drive on one side, and two Dumble tube amp inspired voicings on the other. It’s called the Unobtanium Raw, it adds OC45 germanium transistors to the K-style drive for more gain and more compression.

The look and setup of the Unobtanium Raw should be familiar to anyone who has checked out the original Unobtanium, which was launched in December 2022. Both sides of the pedal have their own footswitch. The lefthand side is where you will find the Dumble-inspired tones, with Overdrive Special (ODS) and Steel String Singer (SSS) voicings available via a two-way toggle switch (what the real amplifiers cost you does not bear thinking about). 

Dial in your sound via the Volume, Gain, Tone and Emphasis controls, and away you go. That Emphasis dial is where you can dial in brighter and tighter pick attack, with the knob adding presence and bottom-end response before your electric guitar’s signal gets overdriven. 

What you won’t see is the tweaks to the circuit, and for the Raw version, those amp sounds are described as “glassier and punchier” than the original.

Crazy Tube Circuits Unobtanium RAW

(Image credit: Crazy Tube Circuits)

Now to the K-style side, where the OC45 transistors are selectable via a toggle switch. These will give you more gain. The Stock setting you original germanium diode clipping.

Dial in your sound with the Volume, Gain and Tone controls. You can also toggle between buffered bypass, just like the original Klon Centaur units, and true bypass.

Other cool features include a passive effects loop, that allow you to invite your pedalboard to the party, placing it between the overdrive and amp sides of the pedal, and you can you can use an external footswitch to toggle between the amp voicings on the Dumble side of the pedal.

Under the hood there are internal trimmers to adjust the output gain for the ODS mode, giving you an extra 6dB of gain to simulate driving the power tubes harder, and a low-end trim to adjust the low frequency response of the SSS mode.

It all adds up to a very versatile stompbox, one that will be catnip to those jonesing for that high-end electric guitar tone but without the budget to shop in the vintage market. Priced €339, the Unobtanium Raw is not a cheap pedal, but when you compare it to the gear that inspired its design, it’s a bargain. 

Those who take more than a passing interest in all things transistors will tell you that these NOS germanium transistors do not grow on trees. Once they’re gone, the Unobtanium Raw is gone. But fear not, Crazy Tube Circuits will keep the original Unobtanium in the lineup. 

For more details, head over to Crazy Tube Circuits.

Jonathan Horsley

Jonathan Horsley has been writing about guitars and guitar culture since 2005, playing them since 1990, and regularly contributes to MusicRadar, Total Guitar and Guitar World. He uses Jazz III nylon picks, 10s during the week, 9s at the weekend, and shamefully still struggles with rhythm figure one of Van Halen’s Panama.