Carvin Quad-X 4 channel tube preamp with footswitch

Carvin Quad-X 4 channel tube preamp with footswitch. Recorded product details are listed below.

• Brand: Carvin
• Condition: Used
• Category: Guitar & Bass/Amplifiers/Electric Guitar Amplifiers/Guitar Preamps
• SKU: 2K4-Quad-X
  
  Carvin Quad-X 4 channel tube preamp with footswitch
  
  The Carvin Quad-X Amp is a legendary, highly versatile 1990s 2U rackmount tube guitar preamp famously known for its "Tube Cascade™" design utilizing nine 12AX7 preamp tubes. 
  
  
  Core Specifications & Signal Path
  
  The preamp utilizes the 9 tubes across four distinct channels, layering triode stages to achieve an incredible amount of cascading high-gain saturation:
• Channel 1 (Clean 1): Uses 1 tube stage (half of V1). Features Volume, Low, Mid, High, and a Bright switch.
• Channel 2 (Clean 2): Uses 1 tube stage (the other half of V1). Features Volume, shared Low/High EQ, and a unique Cloaking control (a bottom-end definition filter) shared with Channel 3. 
• Channel 3 (Crunch): Uses 5 tube stages (V2, V3, and half of V4). Includes Volume, Drive, and shares the Low/High/Cloak controls. 
• Channel 4 (Sustain): A true high-gain beast utilizing a staggering 11 tube stages (the other half of V4 plus V5 through V9). Features dedicated Volume, Overdrive, Low, Mid, and High controls. 
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• Master Tone-Shaping & Routing
• Onboard Features: Includes a built-in, assignable 5-band graphic EQ, an integrated Noise Gate, and a genuine internal Accutronics spring reverb tank. 
• Unmatched I/O & Loops: The routing on the back panel is massive. It features six total effects loops—individual FX loops for each of the 4 channels, a master loop bypass, and a master stereo loop. It also features cabinet-simulated XLR and 1/4" outputs for direct recording or running straight to a PA. 
• The FS-77 Footswitch & MIDI VersionsThere are two distinct generations of the Quad-X that dictate how the proprietary Carvin FS-77 footswitch interfaces with it: 
• The Early Version: Uses a series of 1/4" switching jacks on the back panel. If you use it without the original footswitch, you need a 1/4" relay switcher (like a Voodoo Lab or Control Switcher) to automate it via MIDI.
• The Later Version: Features a native 5-pin MIDI jack alongside a standard D-sub/DIN connector for the FS-77, allowing effortless programmable MIDI channel and feature patching. 
• The FS-77 footswitch itself controls channel switching, toggling the graphic EQ, activating the reverb, and engaging the effects loops on the fly.