Greg Gualtieri is one of those people who insist on doing everything
right. I'm a long-time fan of the quality construction and superior
audio performance of his products. I bought the Pendulum 6386
after reviewing it several years ago and then a couple of years
later I had the opportunity to review the Pendulum Quartet which
also blew me away. I was anxious to check out the new Quartet
II, Mercenary Edition ($5,250). Designed with the input of Mercenary
Audio's Fletcher, it includes several additional options over
the Quartet that allows the user to shape the audio character
for maximum musical flexibility and, in many ways, it is the
perfect compliment to the Quartet (which is still being manufactured).
The Quartet II
features the tube mic/DI preamp from the Pendulum MDP-1, the
Delta-Mu tube compressor/limiter from the Pendulum Audio ES-8,
a three-band inductor-based passive tube EQ low shelving,
a mid cut and high peak bands with adjustable Q, and an aggressive
mode, and peak limiter with JFET and MOSFET modes. The box features
a tube-based signal path with pure Class A, high-voltage
circuitry. Each of the Quartet II's components are separate entities
that can be independently accessed via the rear panel.
In order to yield the highest quality sound possible,
the 12.5-inch deep, two rack-space Pendulum Quartet II uses gold-plated
switch contacts, I/O connectors and tube sockets as well as polypropylene
caps and metal film resistors (pairs matched to 0.1%). It uses
two ECC83/12AX7A tubes for input and two 6922/6DJ8 tubes for
output. The gain control tube is a 6ES8/ECC189. On the rear panel
of the 14.5-pound box, a female XLR connector provides microphone
input and a 1/4-inch jack provides DI input. The microphone preamp's
input impedance is 1500 ohm or 10k ohm (transformer balanced
and floating), the line input impedance is 100 Kohm and the instrument
impedance is 10 Mohm on the front panel 1/4-inch jack and 1 Mohm
on the rear panel jack.
The rear panel's nine 1/4-inch jacks located between
the input and output connectors are used to patch in and out
of the mic/DI preamp, EQ, compressor and limiter or to insert
other equipment into the signal chain. A male XLR connector wired
pin two hot provides the Quartet's transformer balanced output
and a 1/4-inch TRS jack provides unbalanced output. The Quartet
gets its power through an IEC socket that connects to a standard
three-prong IEC power cable (included). The voltage selector
switch allows the box to easily be switched between 115 volts
and 230 volts. To insure the longest possible tube life, the
Quartet II's soft start sequence gently applies power to the
tubes and stabilizes the circuit before engaging the outputs.
The Full/Focused switch in the Mic/DI preamp
section switches between two drastically different sounding input
transformers and loading options. The Full setting has a ratio
of 1:5 and the Focused setting ratio is 1:10. I found that in
most instances, I preferred the sound in the Focused position.
The only exception to this was recording acoustic guitar (strummed
not picked), violin and viola. The 1500/10K switch changes the
load impedance seen by the microphone. The DI Input switch selects
between Instrument (10 Mohm at the front 1/4-inch jack, 1 Mohm
at the rear jack) and line (100 Kohm) inputs. The MIC/DI switch
selects the MIC input (via the rear panel XLR input connector)
or the DI input signals (via the front or rear 1/4-inch input
jack). The +48V switch activates 48 volt phantom power and the
0/-20 switch inserts a 20 dB pad before the microphone's input
transformer. The ± switch reverses the phase of the microphone
signal and the Lo Cut switch applies an 18 dB/octave low frequency
rolloff at either 75 Hz or 150 Hz. The Gain control adjusts the
gain in 3dB steps from +33 dB to +63 dB for the full mic input,
+40 dB to +70 dB for the Focused mic input, +20 dB to +50 dB
for the DI instrument input, and 0 to +30dB for the DI line input.
The Output control adjusts the output level of the preamp stage.
By varying the ratio between the gain and the output control,
the harmonic content of the preamp can be varied.
The three-band tube Passive/Aggressive Equalizer
is a modern take on the classic inductor-based passive EQ. It
features simultaneous Lo Shelf boost and cut, Mid Dip and Hi
Peak bands. The Hi Peak provides up to +20 dB (bandwidth-dependent)
of gain from 0.8 kHz - 18 kHz. The Mid Dip provides up to 20
dB (bandwidth-dependent) from 200 Hz - 800 Hz. The Lo band features
up to 20 dB of shelving from 20 Hz - 120 Hz. The EQ - µ
/ µ - EQ switch places the EQ before or after the compressor.
When the EQ is activated, a blue LED is illuminated. When the
Aggressive mode is activated, the saturation of the EQ circuit
is increased to add harmonic content (nice!).
The delta-mu compressor has the classic compression
profile of the Fairchild 660 and 670 limiters. It features separate
threshold and output (up to +15 dB of gain makeup) controls.
The Mode switch selects the mode of compression. The five options
include: Fast and Faster (both peak-averaged), Average (rms detection),
Vintage (program dependent attack and release times), or manual
(attack 1 ms - 100ms, release 0.1-2s). The Sidechain Lo-Cut switch
reduces detector sensitivity below 150 Hz.
The new JFET/MOSFET Peak Limiter has JFET and
MOSFET modes for two different characters of peak limiting. Unlike
other designs, the peak limiter adds no appreciable distortion
below threshold. In this section, the Ceiling function determines
the maximum output level for peak limiting and the JFET/MOSFET
selects the mode of FET peak limiting. The nine-segment LED display
indicates the amount of peak limiting applied to the signal.
The Compressor/Output switch determines whether the illuminated
VU meter indicates level of gain reduction or the output signal
level. The meter is electronically isolated from the signal path
and is calibrated to 0VU = +4dBu (1.23Vrms).
I had repeatedly
returned to the vocal sound on a rock project that I was mixing
a few months back and just couldn't get it right. Over the period
of a week, I had literally tried everything in my arsenal and
nothing was nailing the aggressive sound that the artist and
I were looking for. That was the day the Pendulum Quartet II
arrived. I hooked it up and was immediately amazed. When the
artist walked in I simply told him to have a listen, I didn't
want him to have any preconceived notions. At the end of the
first chorus he stopped the playback and yelled, "You got
it, that's the vocal sound!" Since then, every time I've
put the box to work on vocals I've been pleased. I used it to
record both male and female vocals with the Sony C-800G, the
Blue Microphones Cactus and the Brauner VM-1KHE and had wonderful
results in every instance. The box also does an amazing job adding
tube character to vocals recorded through solid state microphones.
As was the case with the Quartet, I had good results using an
XLR to 1/4-inch adapter to plug the mic into the rear panel DI
input and completely bypass the input transformer. In most instances
I prefer the sound of the 'focused' transformer on lead vocals
and the 'full' transformer on backing vocals.
I recorded bass guitar through the instrument
input and ended up with a big, phat tone that wasn't lacking
in presence and definition. The box coupled with an Earthworks
SR-25 did a wonderful job capturing the sound of my Taylor acoustic
guitar. The top-end had a wonderful sparkle and sheen without
ever sounding harsh or edgy and the bottom end was rich and big.
The box also worked extremely well for recording electric guitars
with a Royer R-122.
I had superb results using the box to record
kick drum with a Heil PR-40, snare drum with a Shure SM-57, hi-hat
with a Neumann KM-86i and shaker and tambourine with a Royer
SF-1. There were several instances where I used the mic pre in
one signal path, the EQ on another and the compressor and limiter
on another. Each section performed flawlessly. The ability to
simultaneously use each of the four components completely independent
from the others is a wonderful thing. This is not possible with
most of the all-in-one boxes that I've encountered. I occasionally
found that I needed to supplement the Quartet II's EQ with a
GML 8200. The Quartet II's EQ sounds wonderful but it is fairly
limited so if extreme sonic manipulation is required it will
likely require the addition of a more flexible EQ.
Quartet II squashes a load of features, phenomenal sound, extreme
flexibility, and a tube-based signal path with pure Class A,
high-voltage circuitry into a single package. The box is a bit
pricey but worth every cent.
Russ Long, a Nashville-based producer/engineer, owns The Carport
recording studio. He is a regular contributor to Pro Audio
Key Features: Single-channel; preamp; delta-mu compressor; three-band
EQ; limiter; 20 dB pad for preamp
Contact: Pendulum Audio at 908-665-9333, www.pendulumaudio.com.
+ Fantastic sound
+ Preamp, EQ, compressor and limiter can each be accessed individually