Guiter Effects Processor

BOSS’s Flagship Multi-Effects Floor Processor

  • COSM


The successor to the GT-8 is now available. Meet the new flagship of the BOSS multi-effects family, GT-10!

BOSS’s Flagship Multi-Effects Floor Processor

Double your power with BOSS’s new GT-8 floor-based mega processor. Loaded with twin COSM modeling engines, it brings unprecedented performance and tonal control to the stage and studio. The Dual COSM amp section provides two discrete amp channels; you can layer and manipulate each engine independently to create wildly expressive sounds. Thanks to the Solo Switch function, lead sounds can be immediately activated — perfect for ripping through the mix. BOSS’s mega-popular GT-6 was a smash hit with guitarists, now the GT-8 is destined to become the go-to box for gigging and recording guitarists alike.

  • - BOSS’s most powerful floor-based processor!
  • - Dual COSM Amp engine allows two different amp types to be assigned to the two channels
  • - Amp channels can be switched, layered, or panned in real-time; Dynamic mode allows channel switching by picking dynamics
  • - 200 stunning preset patches and 140 user patches; 44 effects categories, up to 13 simultaneous FX blocks
  • - User configurable effect chain; any effect can be in any order in the signal path; independent External Effects loop section for inserting external effects anywhere in the signal patch
  • - Solo Switch on the COSM amp section for instant lead tone
  • - Amp Control jack for switching external guitar amp channels
  • - 24-bit converters and coaxial digital output for high-resolution recording applications
Relevant product

Dual COSM Amps

The GT-8 boasts the latest top-quality COSM amp models with complete dual channel configuration. Explore new sonic dimensions by combining two amp models, or by switching between them during performance. Select a high-gain amp such as Metal Stack and set it for deadly distortion. Then add clarity to the raw power by using the Smooth Drive model on the other channel. Prepare to be impressed as you tap into the expressive Dynamic mode, where two channels can be controlled based on picking strength. Transition smoothly from clean to mean by simply picking harder or softer.

Solo Switch

Step into the spotlight with the new Solo Switch feature. Each of the 46 COSM amp models contains a specially programmed variation that’s optimized for soloing. Simply click the Solo switch to activate the lead tone, and off you go — it’s like having a separate solo channel on every COSM amp!

Extreme Effects

Forty-four effects categories are built into the GT-8. Up to 13 effect blocks can be used simultaneously to create complex textures and routings. All of your FX bases are covered — compressors, reverbs, choruses, EQs, COSM-modeled wahs, and much more. There are 200 preset patches built into the GT-8, plus 140 user patches for storing your custom amp/effects creations. As a special bonus, there’s a selection of synth waves onboard, plus sitar and an acoustic processor. From subtle to sizzling, where will you take your tone?

Effects Chain

Another area where the GT-8 stomps the competition is in its powerful effects routing. Internally, the 13 FX blocks can be configured in any order you desire (for example, you can freely assign an equalizer after a distortion effect or before it). And if you’d care to take your tone “outside the box” and incorporate some external effects into the GT-8’s signal path, you can do so with the Ext Loop send and return. Flexibility in routing is the name of the game.


The GT-8 is stocked with enough I/O options to satisfy even the most demanding pro. In addition to its stereo analog outs, it offers a 24-bit coaxial output for ultra-clean digital transfer, an Amp Control jack for switching between two amp channels on an external amp, an external expression/control pedal input, effects send and returns, MIDI in and out, and a headphone output.

AD Conversion
24 bit + AF method*
DA Conversion
24 bit
Sampling Frequency
44.1 kHz
Program Memories
340: 140 (User) + 200 (Preset)
Nominal Input Level
INPUT: -10 dBu
RETURN: -10 dBu
Input Impedance
INPUT: 1 M ohms
RETURN: 220 k ohms
Nominal Output Level
SEND: -10 dBu
Output Impedance
OUTPUT: 2 k ohms
SEND: 2 k ohms
Digital Output
Dynamic Range
100 dB or greater (IHF-A)
16 characters, 2 lines (backlit LCD)
2 characters, 7 segment LED
INPUT jack
SEND jack
DIGITAL OUT connector (coaxial)
MIDI connectors (IN/OUT)
AC Adaptor jack
Power Supply
AC 14 V; Supply AC adaptor (BOSS BRC series)
Current Draw
650 mA
AC Adaptor (BRC series)
Owner’s Manual
Foot Switch: FS-5U, FS-5L, Dual Foot Switch: FS-6
Expression Pedal: EV-5 (Roland), FV-300L + PCS-33 (Roland)
Foot Switch Cable: PCS-31 (Roland), (1/4 inches Phone Plug (stereo) - 1/4 inches Phone Plug (mono) x 2)

Size and Weight

Width (W)
515 mm20-5/16 inches
Depth (D)
261 mm10-5/16 inches
Height (H)
75 mm3 inches
4.8 kg10 lbs. 10 oz.

* 0 dBu = 0.775 Vrms
* AF method (Adaptive Focus method)
This is a proprietary method from Roland that vastly improves the signal-to-noise (S/N) ratio of the A/D and D/A converters.

All specifications and appearances are subject to change.


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