BOSS GM-800 ZEN-Core Guitar and Bass Synthesizer with Serial GK

BOSS GM-800 ZEN-Core Guitar and Bass Synthesizer with Serial GK

The BOSS GM-800 guitar and bass synthesizer combines the Serial GK digital interface with the ZEN-Core synthesis engine for expressive instrument-controlled synthesis. It provides more than 1,200 preset tones, over 70 drum kits, four playable Tone parts plus Rhythm, extensive effects, and advanced pitch tracking in a compact floor-based performance processor.

Designed for guitarists and bassists using a compatible divided pickup, the GM-800 supports layering, alternate tunings, individual-string assignments, fret-range assignments, and continuous or chromatic pitch behavior. Its 150 Scene locations store complete performance setups, while four onboard footswitches and two external control connections provide hands-free access to sound changes and assignable functions onstage.

The GM-800 also functions as a USB audio/MIDI interface and standalone ZEN-Core MIDI sound module. Serial GK input and output support compatible GK-5 and GK-5B pickups and expansion between Serial GK devices, while standard five-pin MIDI, USB computer connectivity, USB flash-drive storage, stereo outputs, and BOSS Tone Studio integration support live, studio, and computer-based workflows.

Key Features

• ZEN-Core Synthesis Engine: Provides more than 1,200 preset tones spanning acoustic instruments, keyboards, orchestral sounds, classic synthesizers, and modern electronic textures.
• Serial GK Tracking: Uses BOSS's digital divided-pickup interface with dedicated high-speed processing for accurate guitar and bass tracking.
• Five-Part Sound Structure: Combines four playable Tone parts with a dedicated Rhythm part for layered and split performance setups.
• 150 Scene Locations: Stores complete performance configurations including tones, effects, sensitivity, assignments, pitch settings, and other parameters.
• Extensive Effects Processing: Provides dedicated multi-effects and EQ for each part, two Scene MFX processors, chorus/delay, reverb, Master EQ, and Master Compressor.
• Guitar-to-MIDI Operation: Converts compatible divided-pickup performance data for controlling computer instruments and external MIDI sound modules.
• USB Audio and MIDI: Connects directly to a computer for DAW audio recording, MIDI transmission, sound editing, and re-synthesis workflows.
• Expandable GK System: Supports GK-5 and GK-5B pickups directly and can interface with compatible legacy 13-pin GK equipment through optional converters.

ZEN-Core Sound Engine with Four Tones Plus Rhythm

The GM-800 brings BOSS guitar synthesis into the ZEN-Core ecosystem. Four independent Tone parts can be layered, split by string, or assigned to selected fret ranges, while the fifth Rhythm part provides acoustic and electronic percussion. The internal library includes at least 1,200 preset tones and 70 preset drum kits, plus storage for 256 imported tones.

Advanced Serial GK Tracking

A compatible Serial GK divided pickup sends individual-string information to the GM-800 through its 1/4" TRS GK input. Dedicated tracking processing analyzes pitch and playing dynamics for responsive synthesis, while settings for velocity response, pitch behavior, sensitivity, alternate tuning, individual strings, and fret regions allow the system to be tailored to different instruments and playing styles.

Scene-Based Performance Workflow

Each Scene stores a complete collection of performance settings rather than a single tone. Tone selections, part levels, string assignments, effects, sensitivity, control assignments, and other parameters can be recalled together. The GM-800 provides 150 user-configurable Scene locations, with 100 populated with ready-to-play sounds from the factory.

Deep Multi-Effects Processing

Every Tone and Rhythm part has its own 93-type multi-effects processor and dedicated EQ. Two additional Scene MFX processors can operate in serial or parallel, while seven reverb types and nine chorus/delay types handle ambience. Master EQ and compression provide final system-wide shaping before the outputs.

Footswitch and Expression Control

Four built-in footswitches provide Scene Down, Scene Up, CTL 1, and CTL 2 operation. The two rear control jacks can each accept an expression pedal or support two compatible footswitch controls, expanding hands-free command over parameters such as hold, pitch bend, Tone selection, effects, and other assignable functions.

USB Audio, MIDI, and Computer Editing

The USB-B computer port supports high-speed USB audio and MIDI, allowing GM-800 sounds to be recorded directly into a DAW. Guitar-to-MIDI data can control software instruments, and the ZEN-Core engine can operate as a standalone MIDI sound module. BOSS Tone Studio provides detailed Scene editing, tone organization, sensitivity adjustment, and librarian functions from a computer.

Serial GK and Legacy GK Expansion

The GK input connects directly to compatible GK-5 guitar and GK-5B bass divided pickups using an optional BGK Serial GK cable. A dedicated GK output can pass the divided-pickup signal to another compatible Serial GK device. Optional GKC-AD and GKC-DA converters integrate compatible equipment that uses the earlier 13-pin GK connection.

Technical Specifications

• Brand: BOSS
• Model: GM-800
• Product Type: Guitar and Bass Synthesizer
• Sound Generator: ZEN-Core
• Parts: 5 total; 4 Play parts and 1 Rhythm part
• Preset Tones: 1,200 or greater
• Imported Tone Capacity: 256
• Preset Drum Kits: 70 or greater
• Scenes: 150
• Factory-Populated Scenes: 100
• Part Multi-Effects: 1 system per part, 93 types
• Part EQ: 1 system per part
• Scene Multi-Effects: 2 systems, serial or parallel selectable, 93 types
• Reverb: 7 types
• Chorus/Delay: 9 types
• Master Processing: Master EQ and Master Compressor
• Nominal Output Level: -10 dBu
• Maximum Output Level: +7 dBu
• Output Impedance: 44 ohms
• Recommended Output Load: 10 kohms or greater
• Recommended Headphone Load: 44 ohms or greater
• Built-In Footswitches: Scene Down, Scene Up, CTL 1, CTL 2
• Part Controls: Part 1-4 buttons and Part R button
• Navigation Controls: Exit, Write, Menu, Page buttons, Select knob
• Parameter Controls: 4 parameter knobs
• Output Control: Output Level knob
• Display: 256 x 80-dot graphic LCD
• GK Input: 1 x 1/4" TRS, Serial GK for BGK cable
• GK Output: 1 x 1/4" TRS, Serial GK for BGK cable
• Left/Headphones Output: 1 x 1/4" TRS
• Right/Mono Output: 1 x 1/4"
• External Control: 2 x 1/4" TRS CTL/Expression jacks
• MIDI Input: 1 x 5-pin DIN
• MIDI Output: 1 x 5-pin DIN
• USB Computer: USB-B with High-Speed USB, USB Audio, and USB MIDI support
• USB Memory: USB port for compatible flash drive
• External Memory: USB flash drive, sold separately
• Audio Interface: USB audio support
• Guitar-to-MIDI: Supported over USB and MIDI output
• Compatible Divided Pickups: BOSS GK-5 for guitar and GK-5B for bass, sold separately
• Compatible Serial GK Cables: BGK-15 and BGK-30, sold separately
• Legacy GK Conversion: Optional GKC-AD and GKC-DA converters
• Compatible Optional Footswitches: FS-5U, FS-5L, FS-6, FS-7
• Compatible Optional Expression Pedals: EV-30, FV-500L, FV-500H, Roland EV-5
• Power Supply: Included AC adapter
• Current Draw: 840 mA
• Auto-Off Power Consumption: 0.2W
• Battery Operation: Not supported
• Dimensions Without Rubber Feet: 9.7" W x 5.3" D x 2.5" H
• Dimensions With Rubber Feet: 9.7" W x 5.3" D x 2.6" H
• Weight: 2.6 lb, excluding AC adapter

What's In the Box

• BOSS GM-800 Guitar Synthesizer
• PSB-1U AC Adapter with AC Cord Set
• Quick Start Guide
• Safety Leaflet
• 4 Rubber Feet