Recording - January 2017 - 56

B Y PA U L V N U K J R .

Kush Audio Tweaker
A compressor for engineers who love to tweak

Kush Audio is the playground of
audio engineer and gear designer
Gregory Scott, also known by his internet handle UBK. Kush Audio is all about
vibe, and being just a bit different from
the norm. This is exemplified by the Kush
gear we've reviewed in past years: the
Claraphonic Parallel Equalizer (March
2013), the Electra Electrified Transient
Equalizer (hardware March 2014, plugin version December 2015), and the
piece that started it all-Greg's modified
version of the Empirical Labs EL7 Fatso
Jr. known as the UBK Fatso (May 2011).
While the UBK Fatso was technically
the first compressor in the Kush family, it
is more of a modification than a full-on
Kush design. This month we look at the
newest member of the Kush line, a wonderfully unique compressor even in
today's wide landscape of processing
possibilities. Gregory bills it is as his
"masterpiece... a vintage soul that's
evolved for modern musicmaking," and
aptly its name is the Tweaker.
Let's get Tweaked
The Tweaker is a vintage-style discrete
VCA compressor with a custom detector
circuit and unique envelope-shaping controls and side chaining. Its origins go
back to Kush's first plug-in offering, the
UBK-1-itself a unique compression and
saturation device with no real world
counterpart. In many ways the Tweaker
is an expanded UBK-1 in hardware
form. They are not identical in looks or
controls, but they are definitely first
cousins.
The Tweaker is a mono 19" 1U rackmount device finished in Kush's "I need
a latte" coffee coloring with white and
black accents. Eight of the knobs are
high-torque 21-step pots and there is
56

RECORDING JANUARY 2017

one 6-position stepped switch as well.
These are the nicest feeling and highest
quality controls on a Kush unit to date.
Ins and outs on the Tweaker are pretty
straightforward: a balanced XLR input, a
choice of Balanced XLR or TRS out, XLR
I/O for the external sidechain, and a
TRS jack for the stereo linking of two
units.
Tweaker tour
The Tweaker is made up of three sections that all work together, and while we
will look at the unit going left to right, the
layout of the controls does not follow its
signal flow.
On the far left is the input/output section with three controls for Drive, Mix,
and Output. While Mix handles in-thebox parallel compression, and Output is
pretty self-explanatory, the Drive section
is not an input control...
As with a traditional vintage compressor, there is no input level control other
than what you send into the Tweaker.
Instead, the Drive control increases or
decreases the VCA circuit's output. This
gives the compressor different saturation
flavors rather than just being an overdrive control pushed into an output. Low
levels yield a clean compression that gets
more saturated and colored at medium
and moves to a gritty sound at high. You
need to hear it for yourself, but it is a
hint-of-vintage grit that lays into the signal
rather than just buzz and fuzz.
Next on the front are the on/off and
bypass buttons followed by the
Threshold section. Here again are three
of the semi-stepped controls. First is
Threshold, complete with an LED that
lights and pulses as the threshold is
crossed. Then comes the Sidechain control section. Unlike the usual sort of

sidechain control that allows chosen lowfrequency content (below a fixed or variable frequency) to pass through the
threshold circuit without causing it to
clamp down, the two controls here could
be considered the Tweakiest section on
the Tweaker.

On the right is the Sidechain Shaper
with settings of Flat, 60Hz HPF, 300Hz
HPF, Treble Smash, Edge Contouring,
and XLR Insert. The first three settings are
fairly standard compressor fare that functions as described above. The next one,
Treble Smash, does just that; it only compresses the upper end of the spectrum
and can add a great clampdown to
cymbals, horns, tambourines and the
like. The next setting, Edge Contouring,
engages the Contour control knob.
Functionally, it affects the detector circuit
like a see-saw. When turned clockwise,
high-frequency detection increases while
low-frequency detection decreases, and
turning the knob counterclockwise does
the reverse. The last setting engages a
standard rear XLR input to add an EQ
for classic external sidechain filtering.
Three meters in one
The Tweaker contains the most unique
LED metering I have ever seen or used
on a compressor. On most compressors
the meter gives you a choice of input
level, output level, or gain reduction, and
more often than not just gain reduction.
The Tweaker's meter is a trident-shaped
set of LED lights that glow green to yellow to red and show input on the left,
output on the right and gain reduction
straight up the middle. This allows you to
see how all three work together at the
same time, no switching needed. It also
looks cool in a dimly lit control room!
Nice Curves
The last section offers Attack, Release,
and Curve controls. Attack ranges from
10 microseconds to 70 milliseconds,
and Release is switchable between a single (Fast) or dual release constant, 20 to
500 milliseconds in Fast and 500 to

Table of Contents for the Digital Edition of Recording - January 2017