Pendulum Audio ES-8 User manual
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Manual
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PRESETS
Zero
GainReduction
Output
Input
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Fast
Presets
Manual
Gain Reduction
InputOutput
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Pendulum Audio
Off
Max Off
Max Off
Max
Off
Max Off
Max Off
Max
6386
METER
THRESHOLD OUTPUT
INPUT
METERTHRESHOLDINPUT OUTPUT
Variable Mu Tube Limiter
ES-8
Vacuum Tube Limiter
ES-8
Remote Cutoff Tube Limiter
Operating Manual
Pendulum Audio, Inc.
PO Box 339, Gillette, NJ 07933
TEL: (908) 665-9333
Web: http://www.pendulumaudio.com
email: info@pendulumaudio.com
Pendulum Audio
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IN BYPASS
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MANUAL
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Manual
PRESETS
PRESETS
Zero
Gain Reduction
Output
Input
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Presets
Manual
Gain Reduction
Input Output
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Max Off
Max Off
Max
Off
Max Off
Max Off
Max
6386
METER
THRESHOLD OUTPUT
INPUT
METERTHRESHOLDINPUT OUTPUT
Variable Mu Tube Limiter
INPUT
120V/60Hz 30W
POWER
ON
1A
OUTPUT
2 1 2 1
SIDECHAIN
INSERT
1
2
6386 Vacuum Tube Limiter
Pendulum Audio, Inc.
Designed By Greg Gualtieri
Serial No.
WARNING: To reduce the risk of fire or electrical
shock, DO NOT expose to rain or moisture. DO NOT
remove covers. Refer servicing to qualified personnel.
For proper operation, be sure to provide adequate
ventilation. Made in USA.
Date Code
ES-8 Condensed Operating Instructions
The Input attenuator controls the signal level to the input trans-
former. Use it to prevent overload of the transformer and gain
control tube. The optimum operating level is 0VU =+4dBu.
The Threshold control determines the amount of gain reduction
applied to the source material. Up to 12dB of gain reduction is
possible.
The Output control is used to increase the signal level after gain
reduction. Up to +20dB of gain make-up is available.
The VU meter can indicate input level, output level, or gain reduc-
tion. Input and output levels are referred to 0VU = +4dBu. The trim
for zero gain reduction is located below the selector switch.
'Hard' bypass switches for comparing the processed sound directly
with the original source.
Links the two channels for stereo operation. When linked, the
Threshold and dynamics processing (fast, preset and manual
modes) are controlled entirely by Channel 1. The Input and Output
controls for the two channels should be set to the same values.
Input Selects the three sidechain operating modes for dynamic control:
Fast: The ES-8 gain control tube is capable of very fast
operation. In this mode, the attack and release times are
0.5ms and 50ms respectively.
Presets: These six attack/release time settings are identical to the
presets on the classic Fairchild 670 limiter. Presets 5 and 6
are program-dependent.
Manual: The attack and release times are continuously variable
from 1-100ms and 0.1-2s respectively.
TRS 1/4" jacks for inserting an outboard EQ into the sidechain.
Use for frequency-dependent compression or de-essing. Tip is send,
and Ring is return. In Link mode, only the channel 1 insert is active.
The XLR and 1/4" connectors for each channel are wired in parallel.
Pin 2 (Tip) is positive phase and Pin 3 (Ring) is negative phase. Input
impedance is 10k!, transformer-balanced. Output impedance is
600!, active-balanced.
Mode
Threshold
In/Bypass
Link/Split
Output
Meter
Inputs and
Outputs
Sidechain
Inserts
ES-8
ES-8
100 100
ES-8 Front Panel Templates
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.3s
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IN BYPASS
ON
0.1s
2s1ms 40ms
1s
MANUAL
RELEASE
20ms
ATTACK
MODE
Zero
IN BYPASS
2s
0.1s
2s1ms 40ms
1s
MANUAL
RELEASE
20ms
ATTACK
MODE
Presets
Manual
PRESETS
PRESETS
Zero
Gain Reduction
Output
Input
2s
Fast
Presets
Manual
Gain Reduction
Input Output
20
10 7532012
3
1
20
10 7532012
3
1
Pendulum Audio
Off
Max Off
Max Off
Max
Off
Max Off
Max Off
Max
6386
METER
THRESHOLD OUTPUT
INPUT
METERTHRESHOLDINPUT OUTPUT
Variable Mu Tube Limiter
ES-8
100100
Session: _____________________ Date: _____________ Source: _________________________ Notes: ________________________
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IN BYPASS
ON
0.1s
2s1ms 40ms
1s
MANUAL
RELEASE
20ms
ATTACK
MODE
Zero
IN BYPASS
2s
0.1s
2s1ms 40ms
1s
MANUAL
RELEASE
20ms
ATTACK
MODE
Presets
Manual
PRESETS
PRESETS
Zero
Gain Reduction
Output
Input
2s
Fast
Presets
Manual
Gain Reduction
Input Output
20
10 7532012
3
1
20
10 7532012
3
1
Pendulum Audio
Off
Max Off
Max Off
Max
Off
Max Off
Max Off
Max
6386
METER
THRESHOLD OUTPUT
INPUT
METERTHRESHOLDINPUT OUTPUT
Variable Mu Tube Limiter
ES-8
100100
Session: _____________________ Date: _____________ Source: _________________________ Notes: ________________________
LINK SPLIT
.1s
1-
4s
1s
.5-20s
.3s
Fast
.5-20s
1-
4s
1s
.3s
.1s
IN BYPASS
ON
0.1s
2s1ms 40ms
1s
MANUAL
RELEASE
20ms
ATTACK
MODE
Zero
IN BYPASS
2s
0.1s
2s1ms 40ms
1s
MANUAL
RELEASE
20ms
ATTACK
MODE
Presets
Manual
PRESETS
PRESETS
Zero
Gain Reduction
Output
Input
2s
Fast
Presets
Manual
Gain Reduction
Input Output
20
10 7532012
3
1
20
10 7532012
3
1
Pendulum Audio
Off
Max Off
Max Off
Max
Off
Max Off
Max Off
Max
6386
METER
THRESHOLD OUTPUT
INPUT
METERTHRESHOLDINPUT OUTPUT
Variable Mu Tube Limiter
ES-8
100100
Session: _____________________ Date: _____________ Source: _________________________ Notes: ________________________
ES-8 Remote Cutoff Tube Limiter
Features
•Classic feedback compression with the same compression profile as the Fairchild 660 and 670
•Modern class A, solid-state gain make-up stage for wide bandwidth and low distortion
•Soft-knee design with smooth transition from compression to limiting
•Fast attack (0.5ms) and release times ideal for tight program compression or tracking
•Low noise and superior transient response
•Three sidechain operating modes: Fast, Presets and Manual
•Two completely independent channels with stereo linking
•Tubes calibrated for precise stereo balance
•Hard bypass switches for each channel
•Sidechain inserts for frequency-dependent compression and de-essing
•Transformerless balanced output stage capable of delivering +27dBu
•Soft-start warm-up with outputs bypassed until all voltages are stabilized
•Gold-plated relay contacts, I/O connectors and tube sockets
•Fully regulated high voltage (250V), filament and bipolar power supplies
•Custom toroidal power transformer with shield for minimum hum
•Polypropylene capacitors and metal film resistors
Introduction
Thank you for purchasing the Pendulum ES-8, a modern two channel tube limiter designed to have
the compression characteristics of a vintage unit, but with a higher level of sonic accuracy. Rather
than trying to recreate the past, we decided to taken an entirely different approach. The ES-8 uses a
remote-cutoff gain control tube with the same compression characteristics as the vintage Fairchild
limiters to provide the classic feedback response unique to the characteristics of this tube. Subsequent
amplification is accomplished with a Class A, balanced transformerless solid-state line amp, rather
than the push-pull transformer output stage used on vintage variable-mu units. The result is a limiter
that possesses the 'dynamic signature' of a classic tube compressor, but with a more accurate, less
colored signal path.
The soft-knee design used in the ES-8 offers effortless dynamic control with a smooth transition
from compression to limiting. In addition, both channels can be operated independently, or linked
with the flip of a switch. When linked, the threshold and attack/release parameters are controlled
entirely by channel 1, assuring precise stereo balance over the entire range of gain reduction.
For maximum versatility, the ES-8 incorporates a solid-state sidechain to provide a wide range of
control with three modes of processing: In the FAST mode, the limiter works extremely fast (0.5ms
attack time), and is remarkably free of the 'pumping' artifacts normally encountered with slow
variable-mu compressors. It's the ideal choice for invisible dynamics processing, either for tracking or
tight program compression.
The PRESET mode consists of six classic attack/release time settings (identical to the Fairchild
670), that are optimized for program compression, including two settings with program-dependent
release times.
The MANUAL mode offers total control over the attack and release times, which is particularly
useful for creative compression effects or for processing bass guitar.
Most important, the hard bypass switches on the front panel conveniently allow a quick
determination of exactly what the ES-8 is, or in most cases, isn't doing to your signal.
Unpacking
The unit was carefully packed at the factory to protect against damage in transit. Nevertheless, be
sure to inspect the unit and shipping carton for any signs of damage that may have occurred during
shipment. If there is any damage, notify us immediately for further instructions. It’s also a good idea
to save the carton and packing materials should you ever need to return the unit for repair. The
shipping carton should contain the following items: the ES-8 Vacuum Tube Limiter, a 3 prong IEC
power cord, and this operating manual.
Mounting
The ES-8 uses two EIA-standard rack spaces, and can be mounted in any standard 19 inch (483mm)
equipment rack. If the ES-8 is mounted in a mobile rack or road case, it is important that the rear of
the chassis is supported to prevent possible damage from mechanical shock and vibration. Excessive
shock and vibration can cause damage or premature failure of the vacuum tubes, or cause them to
shaken loose from their sockets. Please avoid rough handling.
Ventilation
For proper operation, it is very important that adequate ventilation is provided. Vacuum tubes
produce a significant amount of heat that must be removed from inside the chassis. The side panel
vent holes and top panel slit vents should never be blocked in any way. Never mount the ES-8 below
a rack unit with a depth greater than 7 inches (178mm). Do not mount the ES-8 near other heat-
producing equipment such as power amplifiers or other vacuum tube products. If possible, leave open
at least one rack space above the unit, and use a rack spacer with a ventilation grille. Never operate the
ES-8 inside a road case where the side panels are cushioned in foam.
Preventing Ground Loop Hum
One of the reasons the ES-8 sounds so good is that it uses an active-balanced output stage rather
than an a push-pull output transformer. However, it does not benefit from the galvanic isolation
provided by an output transformer. For this reason, a few precautions are necessary to insure hum-free
operation:
• Isolate the front panel from the rack rails. Use plastic shoulder washers to prevent electrical contact
between the rack ears of the ES-8 and the metal rails of the equipment rack.
• Isolate the ES-8 from units mounted above or below it in the rack. Make sure the front panels are
not in electrical contact and that the top or bottom cover screws of the ES-8 are not touching those
of any other units.
• Connect the 3 prong IEC power cord to the single-point star grounded electrical source for your
facility.
The idea here is to make sure the ES-8 seeks ground at only one point. For safety reasons, do not
lift the ground at the IEC power cord. Keep in mind that in a properly grounded hookup, the ES-8
does not hum. Please, take the time to do this right, and you will be rewarded with hum-free
operation. Call us if you have any questions. Please note that pin 2 is hot.
Power Requirements
The ES-8 is equipped with a 3-prong IEC power connector and detachable cord. Never operate the
ES-8 with the ground on the power cord defeated. Unless otherwise stated, this unit operates from
120V/60 Hz at 30W. The ac fuse is accessible from the rear panel and is rated at 1A/250V (3AG)
SLO-BLO. To check or replace the fuse, make sure the unit is unplugged. Operation at 240V/50Hz is
available as an option. Please contact us for more information.
Servicing
Other than changing the tubes, the user should not attempt to service the ES-8 beyond that
described in this manual. Never remove the covers or attempt to replace the tubes until the unit has
been disconnected from the ac power source, and all circuits inside have been allowed to discharge for a
period of at least 30 minutes. The vacuum tubes become very hot once the unit has been turned on,
and they should not be touched until they have cooled to room temperature. To reduce the risk of fire
or electrical shock, do not expose to rain or moisture, or operate it where it is exposed to water. Since
potentially lethal voltages are present inside the unit, it should only be opened by qualified service
personnel. Refer all servicing, or any questions about servicing, to Pendulum Audio, Inc.
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