Recording - November 2019 - 54

REVIEW

BOSS WAZA Tube Amp Expander
Front, Back, In, and Out

REVIEW BY ALEX HAWLEY

OSS first introduced the WAZA series in 2014 with the reintroduction
of three popular BOSS pedals; the Blues Driver, the Custom Super
Overdrive Pedal, and the Custom Delay Pedal.
Since then, the line has expanded to include additional pedals, a guitar
amp, speaker cabinet, and now the Tube Amp Expander. WAZA represents
the BOSS premium line with refined circuitry and upgraded analog components. In Japanese, waza translates to 'art and technique'.
The Tube Amp Expander (TAE) is a fully loaded reactive load box-emphasis on the fully loaded part. It allows for bedroom-comfortable levels or
even the silent use of high wattage tube amplifiers while maintaining the
tone and glory of running the amp in its sweet spot. It comes armed with
built-in FX loop and effects which can be heard through both the live cab
as well direct out. For direct out it features speaker emulation, mic and
room modeling, an, the ability to use it as an audio interface, and more.

Reactive vs. Resistive loads

Reactive loads function differently
than resistive loads. Resistive loads
are more common. They use resistors
to soak up the amplifier's load and dissipate it as heat. Reactive load boxes
are a bit more complex and use twoway communication between the load
box and amp. Different speakers have
different impedance curves and directly affect the tonality of your amplifier.
Your Presence knob is actually just an
adjustment of you speakers high frequency impedance interaction. A reactive load is designed to respond more
54 RECORDING November 2019

like a speaker naturally would and is
accomplished through a network of capacitors and resistors that emulate the
impedance curve of an actual speaker.
The WAZA TAE takes full advantage
of this design with adjustable impedance controls on the front panel of the
unit. The Resonance-Z and Presence-Z
controls model the sound of different
speakers by shaping the impedance
curve of the reactive load. There is a
convenient cheat sheet of impedance
combinations printed on the top of the
unit, so it's easy to dial in the sound of a
4x12 Brit Stack when you need it.

By design, the TAE soaks the amp's
load down to line level and then powers
it back to speaker level with its built in
100-watt power amp. There are several
advantages to this design, including the
ability to keep lower wattage amps in
their sweet spot while being able to get
more volume out of them; just be mindful
of what speaker you are driving, and its
limitations. Another advantage is seamless volume control, as opposed to a
stepped control. Most load boxes/attenuators have fixed speaker output levels
based on percentages of attenuation.
The built-in power amp in the TAE allows for a broader range and seamless
speaker output level. It allows for the
addition of an effect loop and internal
effects through your live speaker cab.
In addition to the reactive load settings, the front panel also includes knobs
for rig preset selection, reverb, line output, and headphone volume. The rig selection can store up to 10 settings at a
time, and is fully customizable using the
WAZA Tube Amp Expander Editor.
There are on/off push buttons on the
front panel for the FX loop, DSP effects,
solo/EQ, and amp control (used for
channel switching the amp). The FX loop
is a useful feature for a load box and
something that I have not seen before.
Most vintage amplifiers don't have one

Recording - November 2019

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