BOSS SY-300 front top side angle
BOSS SY-300 rear view
BOSS SY-300 front top view


Guitar Synthesizer

Product Highlights

  • Guitar Synthesizer
  • Plugs into the standard 1/4-inch jack
  • Play rich and expressive polyphonic synth tones with any guitar
  • Completely latency-free playing feel
  • Three simultaneous synth sections and four effects processors
  • Rich, dynamic, and diverse sound creation
  • Shape your normal guitar tone to create all-new sounds
  • Graphic LCD display, three assignable footswitches, and dedicated on/off footswitch

Sale Price $699.00
Retail Price $979.00
You save $280.00


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BOSS SY-300 Guitar Synthesizer

Discover new dimensions of sound with any guitar! Grab your favorite guitar and journey into the wonderful world of sound creation with the SY-300 Guitar Synthesizer. The SY-300 is compatible with all your guitars straight out of the box, no need for a special pickup —just plug into the standard 1/4" jack and play your heart out! Thanks to BOSS' new cutting-edge technology, you can explore big, analog style polyphonic synth sounds with absolutely no latency, naturally extending the expressiveness and authentic feel of your own instrument. Additionally, you can tweak your regular guitar with the synth’s filters, amps, and LFOs to make all sorts of awesome sounds the world has never before heard. From crazy cool lead textures to rich, ambient soundscapes, the SY-300 adds new dimensions of inspiration and creativity to your music. You may also be interested in the GR-55 Guitar Synthesizer.



BOSS SY-300 Key Features:

  • Plug into the standard 1/4" jack & play rich, expressive polyphonic synth tones w/ any guitar
  • Latency free playing feel connects your hands w/ the sound
  • 3 simultaneous synth sections & 4 effects processors allow for rich, dynamic, & diverse sound creation
  • Shape your normal guitar tone w/ synth filters, amplifiers, & LFOs to create brand-new sounds
  • Graphic LCD display, 3 assignable footswitches, & designated on/off footswitch
  • 70 play-ready preset patches & 99 user patches for saving custom sounds
  • Create & archive sounds on your computer w/ the BOSS Tone Studio editor/librarian & download new sounds at BOSS Tone Central
  • Works w/ bass and other electronic instruments

Access Expressive New Sounds via a Standard 1/4-Inch Input

With the SY-300, tapping into BOSS’ legendary guitar synth technology has never been easier. While our other synth products require a special GK pickup and 13-pin cable to access synth voices, the SY-300 can be used with any guitar via a standard 1/4-inch cable. Powered by ultra-fast DSP and newly developed innovations from the BOSS engineering team, the SY-300 performs its amazing synth magic in real time, with no lag whatsoever. This delivers a latency-free playing experience that’s a natural extension of your normal guitar, letting you to play freely and organically without altering your technique in any way.

A True Analog-Style Synth for Guitar

The SY-300 features a powerful polyphonic synthesis engine with three separate sections, bringing a limitless range of fresh tones to your arsenal. Just like a keyboard player with a classic analog synth, you have complete creative freedom to build sounds with a full palette of synthesis parameters—select different wave shapes, tweak them with filter, amp, and pitch controls, modulate them with LFOs, and layer oscillators for rich, complex tones. There’s even a step sequencer (with tap tempo control) for creating dynamic melodies and arpeggios simply by playing a single note on your guitar! And with the cool Blender function, you can instantly mix and match synth settings from other patches to discover inspiring new sounds with no heavy lifting at all.

Shape Your Normal Guitar Sound with Synth Parameters

Beyond its amazing synth voices, the SY-300’s synth engine can be used to process your normal guitar sound in many compelling ways. Apply filtering to alter the basic tonality, and use the amplifier parameters to alter the attack and decay characteristics. After that, add some sweeping movement to the sound with the LFO section. With these powerful controls, you’re able to extend your regular axe with an endless supply of unique creative textures, from subtle to otherworldly.

Maximize Tones with High-Impact Effects

Effects play a huge role in synthesizer sound design, and the SY-300 is filled with options to take your tones into the stratosphere. Four simultaneous effects engines are available, each packing a number of effects types including overdrives and distortions, Slow Gear, Isolator, Slicer, and many others. Some types can even perform two effects at once, such as chorus and delay or delay and reverb. Use the effects to process synth sounds, your straight guitar sound, or both at once—it’s up to you.

Powerful Control Options and Versatile Connectivity

Controlling the SY-300 while performing is simple. Using the four built-in footswitches, you can bypass the synth sound, scroll through patches, and control three different parameters of your choosing per patch. Two external footswitches or an expression pedal can also be connected for even more real-time control if needed. The Thru output lets you to send your dry guitar sound directly to your pedals or amp, or it can be used along with the Return jack as an effects loop. Dual output pairs (Main and Sub) offer assignable signal routing options to integrate with any setup, while MIDI In and Out/Thru jacks are provided for interfacing with switchers, drum machines, and other MIDI gear.

USB Interface for Computers

The SY-300 is equipped a USB audio interface to capture audio tracks directly into music production software on your computer. You can record the SY-300’s synth and effects sounds, or just monitor them while recording a dry signal. Then, feed that signal back into the SY-300 to “re-synth” the sound and create the perfect tone for your mix. You can feed other tracks from your DAW into the SY-300 as well, processing them with the synth engine and effects to create cool new sounds for your productions. The SY-300’s USB connection also allows you to build and organize patches with the dedicated BOSS Tone Studio editor and download new patches from the BOSS Tone Central website.

BOSS SY-300 Guitar Synthesizer




  • Effect (FX) x 4

Patch Memories:

  • User: 99
  • Preset: 70    

AD Conversion:

  • 24 bits + AF method
  • * AF method (Adaptive Focus method): This is a proprietary method from Roland & BOSS that vastly improves the signal-to-noise (SN) ratio of the AD and DA converters.    

DA Conversion:

  • 24 bits    

Sampling Rate:

  • 44.1 kHz    

Nominal Input Level:

  • INPUT: -10 dBu
  • RETURN: -10 dBu    

Input Impedance:

  • INPUT: 2.2 M ohms
  • RETURN: 220 k ohms    

Nominal Output Level:

  • MAIN OUTPUT: -10 dBu
  • SUB OUTPUT: -10 dBu    

Output Impedance:

  • MAIN OUTPUT: 2 k ohms
  • SUB OUTPUT: 2 k ohms    

Recommended Load Impedance:

  • MAIN OUTPUT L/R: 20 k ohms or greater
  • SUB OUTPUT L/R: 20 k ohms or greater
  • PHONES: 16 ohms or greater    


  • Graphic LCD (132 x 64 dots, backlit LCD )    


  • INPUT jack: 1/4-inch phone type
  • THRU jack: 1/4-inch phone type
  • RETURN jack: 1/4-inch phone type
  • MAIN OUTPUT R (MONO) jack: 1/4-inch phone type
  • MAIN OUTPUT L (PHONES) jack: 1/4-inch phone type
  • SUB OUTPUT R (MONO) jack: 1/4-inch phone type
  • SUB OUTPUT L jack: 1/4-inch phone type
  • MIDI (IN, OUT/THRU) connectors
  • EXP/CTL4, 5 jack: 1/4-inch TRS phone type
  • USB port: USB type B
  • DC IN jack    

Power Supply:

  • AC adaptor    

Current Draw:

  • 400 mA    


  • AC adaptor
  • Owner's manual
  • Leaflet "USING THE UNIT SAFELY"    

Options (sold separately):

  • Footswitch: FS-5U, FS-5L, FS-6, FS-7
  • Expression pedal: Roland EV-5, BOSS FV-500L/500H    



  • 255 mm
  • 10-1/16 inches    


  • 191 mm
  • 7-9/16 inches    


  • 70 mm
  • 2-13/16 inches    

Weight (excluding AC Adaptor):

  • 1.75 kg
  • 3 lbs 14 oz.

Call 1-877-477-6432 for any technical questions or if you need SPECIAL PRICING regarding this product