Boss Waza Tube Amp Expander

More than just an attenuator, the Waza Tube Amp Expander modernizes old tube amps with features like an effects loop, reverb, and a USB output for recording.
Bringing together a diverse range of professional tone tools for the very first time, the Waza Tube Amp Expander elevates the tube amp experience to an amazing level of versatility for stage performing and studio recording. This device does it all -- it's a variable reactive load box, active analog power stage, mic'd cab emulator, IR loader, and recording interface, all in one integrated unit that's road-ready and easy to use.

Get to know the Waza Tube Amp Expander in this video from Boss:

Backed by Boss' advanced Tube Logic approach, you're able to crank your amp to its sweet spot and play at any volume while faithfully retaining the core tone and feel you love. And with extensive connectivity, built-in Boss effects, 10 fully customizable rig setups, and deep real-time control, you have unparalleled creative command for any scenario. Packed to the max with breakthrough Boss innovations, the Waza Tube Amp Expander is an essential companion for every tube amp player.

Waza Innovation for Lovers of Pure Tube Tone

Realized with Waza R&D expertise and the ever-evolving Tube Logic approach, the Waza Tube Amp Expander seamlessly complements and extends your tube amp, and all without affecting the unique tone and response that made you choose it in the first place. The initial concept for this unique device came during the development of the flagship Waza amplifier head. To comprehensively test and refine the amp's AC power voltage and output circuitry, the Boss team devised a read more custom load box with capabilities reaching far beyond those in any commercially available unit. This innovative design performed so successfully that it became the logical foundation for developing a next-generation toolkit for the modern tube amp player.

Cranked-Amp Tone and Feel at Any Volume

As a tube amp owner, you know that it sounds and feels best when it's cranked up loud and really cooking. But if you're like most of us, it's a rare pleasure to be able to open up the volume enough to unlock that full expressive potential. Load boxes and volume attenuators driven by a tube amp's speaker output have attempted to solve this nagging volume issue for years. But while they do lower the volume and provide workable results, they typically introduce artifacts that change the tone, dynamic response, and distortion character, leaving you with an unsatisfying experience.

The Waza Tube Amp Expander's advanced reactive load section completely eliminates these artifacts, allowing you to experience your amp's true cranked-up sound and interactive feel while controlling the volume to suit any situation. A key feature is the Resonance-Z and Presence-Z panel controls, which optimize the all-important impedance interaction with your amp's output transformer. Selecting from sixteen different settings, you can make your amp behave and respond exactly as if it were connected to your favorite speaker cab. Any tube guitar amp up to 150 watts is supported, from vintage combos to modern high-gain heads.

Bigtime Rig Control

Filled with deep control options, the Waza Tube Amp Expander is a dream command center for both stage and studio. Ten different rig setups can be stored in the unit, and each includes your custom effects and EQ settings, cab/IR selections, effects loop on/off, MIDI program change (for controlling external MIDI effects), and amp control status (if you have an amp that supports channel switching). Rigs can be recalled with a panel knob, and additional controls are provided for reverb and other functions. There's also a Write button for saving minor adjustments in the heat of a gig.

Connecting the optional GA-FC foot controller puts full-throttle performance control at your feet. Via a single TRS cable, you have instant access to the 10 rigs, plus real-time control of delay, tap tempo, solo/EQ, effects loop on/off, and amp channel switching. You can even control levels by connecting optional expression pedals to the GA-FC. The Waza Tube Amp Expander also supports FS-series footswitches, plus extensive MIDI control for more advanced setups.

Effects to the Max

With its built-in effects engine and external effects loop, the Waza Tube Amp Expander brings a wealth of sonic enhancements to your tube amp, particularly if it's a vintage model with no effects loop. Onboard DSP delivers premium sound quality and true stereo operation with class-leading 32-bit AD/DA, 32-bit floating-point processing, and 96 kHz sampling rate. Compressor, delay, and reverb effects are on hand, with loads of customizable settings via dedicated editor software. Four different EQs are available for strategically shaping your tone at multiple points in the signal path, and it's even possible to use one of the EQs as a switchable boost for solos. The external loop offers selectable series or parallel operation, plus support for both line-level devices and standard stompbox effects.

Feed Stage Cabs, Mixers, Recording Devices, and Headphones -- All at Once

Once you've dialed in your amp to the sweet spot, the Waza Tube Amp Expander lets you deliver that glorious sound to multiple destinations at once. With parallel speaker outputs, you can drive up to two stage cabs from the integrated 100-watt Class AB analog power stage. Along with providing smooth, non-stepped level control for any connected amp, this robust power stage also opens up the ability to boost a favorite low-wattage amp to stage-ready volumes. Balanced mono and stereo line outputs include tone shaping from mic'd cab emulation or user IRs, providing ready-to-mix direct signals for the main PA mixer, stage monitors, and recording devices. There's a USB output as well, offering another direct feed for tracking with your preferred music production software. And with the dedicated phones output, you can practice with great tube tone without disturbing others nearby.

Intense Customization

The Waza Tube Amp Expander works great out of the box, but connecting to the dedicated editor software via USB unlocks even further creative potential. First off, you're able to edit effects and EQs in micro detail. In addition, you can select from 22 different mic'd cabs for the direct outputs, each with your choice of five adjustable close-mic types plus three room-mic types for adding spaciousness and depth. There are even four user slots for loading your go-to speaker IRs if desired. Other tweaks are available too, including MIDI, system parameters, and a loudness contour for big, full tones at whisper-quiet levels. Favorite rig setups can be saved on your computer and organized as Live Sets for different gigs and recording scenarios.


- First-of-its-kind tube amp command center, built with Waza expertise and the Tube Logic design approach
- Advanced variable reactive load circuit with discrete analog components supports tube amps up to 150 watts
- User-adjustable impedance tuning correctly matches the reactive load to your amp, retaining its natural tone, dynamic feel, and distortion characteristics
- 10 recallable rig settings for storing favorite setups
- Deep real-time performance control via GA-FC/FS-series footswitches and MIDI I/O
- Built-in 100-watt Class AB power amplifier with discrete analog design and seamless volume control
- Powerful DSP section with 32-bit AD/DA, 32-bit floating-point processing, and 96 kHz sampling rate
- Customizable stereo effects with premium tone quality: compressor, delay, reverb, and four EQs
- Twenty-two mic'd cabinet emulations with five selectable close-mic types and three room-mic options, plus four slots for loading user speaker IRs
- External effects loop with selectable series/parallel operation and control jack for switching amp channels
- Parallel speaker outputs for connecting up to two cabs for gigging
- Balanced XLR line outputs (mono and L/R stereo) for connecting to FOH console, stage monitors, and recording devices
- Headphones output for quiet practice with cranked-up amp tones
- Dedicated editor software (Mac/Windows)
- USB for direct audio recording and editor communication
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- From Tube Amp Input:
- Maximum Input Power: 150 W
- Input Impedance: 4/8/16 ohms (selectable)
- Safety Load (power off): 16 ohms
- To Speaker Output:
- Rated Power Output: 100 W (8 ohms)
- Load Impedance: 4-16 ohms
- Nominal Output Level:
- Line Out L/R: +4 dBu
- Line Out Mono (FOH): +4 dBu
- FX Loop Nominal Output Level: -10/+4 dBu (selectable)
- Maximum Output Level:
- Line Out L/R: +20 dBu
- Line Out Mono (FOH): +20 dBu
- FX Loop Send: +6 dBu (-10) /+20 dBu (+4)
- FX Loop Return Input Impedance: 1 M ohm
- Output Impedance:
- Line Out L/R: 600 ohms
- Line Out Mono (FOH): 600 ohms
- FX Loop Send: 1 k ohm
- Controls:
- Power switch
- Speaker Out knob
- Line Out knob
- Phones knob
- Resonance-Z knob
- Presence-Z knob
- Rig knob
- Reverb knob
- FX Loop button
- Effects button
- Solo/EQ button
- Amp CTL button
- Speaker Impedance switch
- Input Level switch
- L/R Ground Lift switch
- Mono (FOH) Ground Lift switch
- Loop switch
- Level switch
- Send Ground Lift switch
- Return Ground Lift switch
- Amp CTL switch
- Indicators:
- Power
- Write
- FX Loop
- Effects
- Solo/Eq
- Amp CTL
- Input Sig/Peak
- Connectors:
- From Tube Amp jack: 1/4-inch phone type
- Speaker Out jacks (Out A, Out B): 1/4-inch phone type
- Line Out L/R connectors: XLR type
- Line Out Mono (FOH) connector: XLR type
- Phones jack: Stereo 1/4-inch phone type
- Send jack: 1/4-inch phone type
- Return jack: 1/4-inch phone type
- FX Loop jack: 1/4-inch phone type
- GA-FC jack: 1/4-inch TRS phone type
- Amp CTL jack: 1/4-inch phone type
- USB Computer port: USB B type
- MIDI (IN, THRU/OUT) connectors
- AC In jack
- Power Consumption: 100 W
- Dimensions (including foots):
- 380 (W) x 296 (D) x 110 (H) mm
- 15 (W) x 11-11/16 (D) x 4-3/8 (H) inches
- Weight: 6.8 kg / 15 lbs
- Accessories: Owner's manual, Power cord, Rack mount angle x 2 (for EIA-2U), GA-FC sticker
Dimensions and Weight in Packaging
Base Item
Shipping Weight: 19.25 lbs
Shipping Dimensions: 18 x 17 x 7 in
Manufacturer Part Number (MPN): BOS WTAE
For support or warranty questions, please contact the manufacturer:
Phone: 323-890-3700
(3 ratings)
Submitted June 11, 2021 by a customer from
"Great, versatile product."
Verified Customer zZounds has verified that this reviewer made a purchase from us.
Great tool for the studio. Havnt used it live yet and might not because of the size and number or connections that would have to be undone to take it out of the studio if you have it fully integrated. The direct out is about the best sounding that I have heard from any "attenuator " . I generally do a lot of re-amping but have found myself not having to do nearly as much because the recorded sound is so good. Roland is not known for customer support and this isnt any different so dont be surprised if the manual is pretty general and you dont receive an answer if you do have any tech issues. it takes a bit but the deeper features are there and just take a bit of patience to figure out. The software is functional but pretty primitive.All in all a large step up from other attenuators including the UA Oxbox.
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