Codename X81
Codename X81
Preamp and Distortion Pedal
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What happens when you take a Valvestate 8100, and conduct unholy experiments on it with the goal of turning it into the most unforgiving chug-machine ever conceived?
You end up with Codename X81 - our hardest hitting preamp to date... and today, the experiment escaped the lab.
One of the first reactions people have when trying an original 8100 is usually: "oh, is that it?". Despite its reputation for extreme metal tones, the original 8100 is relatively restrained on its own. Much of the sound associated with the amp comes from pairing it with a boost and additional EQ to create the tighter, more aggressive response heard on countless heavy records.
So we set out to fix that. This pedal is the result of over 2 years of tweaking and experimenting on the 8100 circuit, with this singular goal in mind. We took the original formula, added more gain, improved the Contour control, added an active 3-band EQ, and gave it more low end energy.
Finally, we bolted an absolutely ridiculous "Integrated Pre" style boost to the front for good measure!
The end result is X81 - a pedal developed for the most extreme genres of metal.
Features
- Heavily modified Valvestate 8100 circuit with added gain
- 3-band active EQ gives extremely responsive tone shaping
- Improved Contour knob
- Boost circuit with a strong mid-frequency character (based on the TC Integrated Pre)
- Usable as either a true preamp or a distortion pedal
- Soft-touch footswitches that persist state, even when disconnected from power
- External control input for operating the pedal with a controller / channel switcher
- Solid steel construction with durable powder coating

Product Details - Codename X81
Controls
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Bass, Mid, Treble - Active 3-band tone control.
- When all 3 controls are set to 50%, the frequency response becomes completely flat.
- Volume - Controls the output signal amplitude.
- Contour - A mid-shaping control, affects mid-range frequency response.
- Gain - Master gain knob.
- Boost Knob - Controls the volume of the boost circuit in front of the main distortion stage.
- Mode Switch - Switch between "Distortion" mode and "Preamp" model (See more details below)
- Boost Footswitch - Activates or bypasses the Boost circuit.
- Active Footswitch - Enables or bypasses the pedal entirely.
Details
The 3-band active EQ produces a completely flat frequency response when all knobs are set to 50% / noon. The mid control has a very wide frequency spectrum, and combining it with the Contour knob allows you to find many different tone variations. The Contour control works over a much narrower frequency band, so experiment with boosting the wider midrange using the Mid knob, and applying a narrow cut with the Contour knob - or scoope the mids while leaving contour at zero.
The Contour knob on the original 8100 behaved in strange ways at the extremes of its control range. We have refined the Contour control to be a bit better behaved, and apply a more modest effect when turning it all the way to the maximum.
The Mode switch works by engaging or bypassing a fixed tonestack - effectively the sound of the original 3-band EQ from the original amp, with all controls set at 50%. When the switch is set to "Dist", this tonestack is bypassed, and the pedal is more suited to being connected to the input of a clean amp, where the amp's own tone controls can be used to shape the tone instead. Of course, this means that the final tone is very dependent on the amp's tone, and different amps may need very different adjustments to sound similar.
The Boost is loosely based on "Integrated Pre" circuit design, and internally boosts the signal by up to 30dB before it hits the main preamp section.
The pedal can be controlled using an external switch, connected via a 1/4" TRS connector. Both footswitches can be toggled using the external switching system.
Technical Specs
- Power Requirement: 9V DC, 190mA
- Power connector: 2.1mm center-negative barrel jack
-
External Switching: 1/4" TRS connection. "Short to ground" operation.
- Tip: Active Footswitch
- Ring: Boost Footswitch
- Sleeve: Ground
- Input Impedance: >1MΩ
- Output Impedance: 1kΩ
- Bypass circuit: Buffered bypass
-
Footswitch mechanism: Momentary, soft-touch, relay control.
- Footswitch state is stored and recalled even when the pedal is disconnected from power.
- Dimensions: 83mm (W) 125mm (D) 55mm (H)
- Dimensions (with packaging): 126mm (W) 146mm (L) 67mm (H)
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