The Crazy Tube Circuits Space Charged is a tube overdrive pedal: a stompbox that uses a real 12AY7 preamp tube as its gain stage rather than clipping diodes or op-amps, taking a signal from clean boost all the way to distortion12. Crazy Tube Circuits describes the V2 simply as "Real tube (12AY7) overdrive !!!"1. The tube runs from an ordinary 9V DC input, which an internal voltage multiplier steps up to about 40V so the tube works in a range where it behaves like it would in an amplifier3.
The V2 is discontinued. Crazy Tube Circuits lists it as "discontinued, old stock" and it is sold out on the maker's webstore1.
What it does: a 12AY7 tube overdrive
Most overdrive pedals shape their clipping with solid-state parts. The Space Charged instead puts a 12AY7 dual-triode tube in the signal path, the same kind of tube used in the preamp sections of amplifiers, and lets the tube itself generate the overdrive. When Guitar Interactive Magazine covered the original pedal in 2017, it described it as a pedal with a 12AY7 preamp tube covering "clean boost to distortion"2.
The 12AY7 is a lower-gain tube than the 12AX7 most players know from amp preamps, which suits an overdrive circuit: it pushes gradually and compresses the way a tube amp does when it starts to break up. Delicious Audio reported that the core real-tube overdrive circuit in V2 is exactly the same as V1's, with the warm tube tone of the original preserved3.
"Preserving that warm tube tone of V1 we've added gain and volume boost function to spice up your solos."
The tube is not fixed. Delicious Audio noted it "can be switched with other tuber models (12AX7, 12AT7, 12AU7, 5751) for varied color and character"3. A 12AX7 will push harder and break up earlier; a 12AU7 stays cleaner longer. That makes the pedal closer to a small tube preamp than a fixed-voiced overdrive.
Power: 9V DC stepped up to 40V inside
A 12AY7 wants far more plate voltage than a 9V pedal supply delivers, so the Space Charged uses an internal voltage multiplier to raise the incoming 9V to an internal 40V3. Guitar Interactive described the same arrangement at the original launch: "powered from a standard 9V DC power supply with an internal voltage multiplier to make the tube feel more comfortable!"2
The input is 9V DC, center negative, the common standard for pedalboard supplies4. The V2 shipped with its own external 9V DC power supply included3.
The pedal draws 430mA4. That is a heavy draw for a single pedal, well beyond what a typical small daisy-chain supply can spare, so it needs a power output with real headroom, ideally an isolated output rated for at least that much current.
History and versions: V1 and V2
The original Space Charged was covered by Guitar Interactive Magazine in January 2017 as part of a set of new Crazy Tube Circuits pedals2. The company presented the V2 at NAMM 20203.
The V2 kept the V1's core tube circuit and tone but added three things3:
- A gain and volume boost function, to help lead parts stand out
- An updated tone control with a wider range, making brighter sounds available
- A tight/fat switch to shape lower frequencies
| Space Charged V1 | Space Charged V2 | |
|---|---|---|
| Tube | 12AY7 preamp tube1 | 12AY7 preamp tube1 |
| Core circuit | Real-tube overdrive, clean boost to distortion2 | Same core circuit as V13 |
| Boost | Not reported | Gain and volume boost function3 |
| Tone control | Standard | Wider range, brighter sounds available3 |
| Low-end shaping | Not reported | Tight/fat switch3 |
| Power supply | 9V DC with internal voltage multiplier2 | 9V DC supply included, 40V internal3 |
The maker's manual for the Space Charged is available as a PDF, covering the pedal's controls and operation for both versions4.
What reviewers and players made of it
For players who want the maker's own account of the pedal, Crazy Tube Circuits publishes the Space Charged manual as a PDF download, covering its controls and operation4.
Videos
Pete Thorn
Rabea Massaad
AndyDemos
Questions
Can you swap the tube in the Space Charged?
Yes. The pedal ships with a 12AY7 preamp tube, and it can be switched with other tube models such as the 12AX7, 12AT7, 12AU7 or 5751 for varied color and character. Each of those tubes has a different gain factor, so the swap changes how the overdrive responds, not just how loud it gets.
Is the Space Charged V2 discontinued?
Yes. Crazy Tube Circuits lists the Space Charged V2 as discontinued, old stock, and it is sold out on the maker's webstore. The V2 was presented at NAMM 2020 and added a gain and volume boost function, a wider-range tone control, and a tight/fat switch for shaping low frequencies.
How much current does the Space Charged draw?
The Space Charged draws 430mA at 9V DC. That is far more than most analog overdrives, because the internal voltage multiplier has to feed a real vacuum tube. A small daisy-chain supply that runs a handful of ordinary pedals may not be able to power it on its own.
Does the Space Charged come with a power supply?
The V2 was powered from an external 9V DC power supply that was included with the pedal, according to Delicious Audio's coverage of the release. The internal voltage multiplier then raises that 9V to around 40V internally so the tube operates comfortably.
Sources (4)
- Space Charged V2 (discontinued, Crazy Tube Circuits
- Crazy Tube Circuits Unveil New Pedals, Guitar Interactive Magazine, 2017-01-22
- Crazy Tube Circuits Space Charged V2 Tube Ovredrive, Delicious Audio, 2022-01-24
- Space Charged by Crazy Tube Circuits, RockBoard (rockboard.de PedalPedia), 2026
