ecler PAM1100 PAM Series Power Amplifier User Manual
- June 17, 2024
- ecler
Table of Contents
ecler PAM1100 PAM Series Power Amplifier User Manual
All numbers subject to variation due to production tolerances. ECLER S.A. reserves the right to make changes or improvements in manufacturing or design which may affect specifications.
IMPORTANT NOTICE
We thank you for trusting on us and choosing our PAM series power amplifier.
In order to obtain the maximum performance and perfect operation, it is VERY
IMPORTANT that you carefully read this manual before connecting the unit,
taking special attention to the marked safety warnings.
We recommend our authorised Technical services if any maintenance task should
be needed so that optimum operation shall be achieved.
1.1. Precautions
The amplifiers, specially the high power models, have a high power consumption
and so, special care must be taken when sizing the mains wiring. We recommend
a 2.5mm2 (or bigger) section for the PAM1100/2100 models and 4mm2 section for
the PAM4100/6100 models. The installation should also dispose of a multipole
magnetothermic circuit breaker or switch with a minimum contact separation of
3 mm between each pole and should handle at least 10 A for PAM 1100/2100 and
25 A for PAM 4100/6100 models. These values are for one amplifier and 220VAC;
double the values if the amplifier operates at 110VAC.
The amplifier must be linked to a proper earth connection which must also be isolated from the machines not related to the audio chain (Earth resistance Rg=30 W or lower).
The environment must be dry and dustless. Do not expose the unit to rain or water splashes, and do not place liquid containers or incandescent objects like candles on top of the unit. Do not obstruct the ventilation shafts with any kind of material.
WARNING! Always disconnect the amplifier from the mains supply before handling and/or connecting or disconnecting it and for additional safety issues wait at least 10 minutes in order to allow the power supply capacitors fully discharge. Never connect the loudspeakers while the amplifier is on! Remember that voltages as high as 400Vpp and up to 150A currents can be present at these outputs. The output cabling should be connected by a qualified technician. Otherwise only use pre-made flexible cables. There are no user or serviceable parts inside the amplifier.
INTRODUCTION
The PAM amplifiers have been designed to fulfil the audio professional requirements of a tough and reliable power amplifier. The models PAM1100 and 2100 represent the fifth generation of SPM Technology (Switching Power Mosfet), developed and patented by ECLER – Laboratorio de Electroacústica S.A., incorporating further improvements upon this technology first used in 1989. These components were only used in switching applications until today and their use in the audio field means a firm and spectacular progress in relation to conventional systems.
This advantages can be summarised as follows:
a) The internal resistance is lower for the switching mosfets than for the
bipolar transistors, meaning that the amplifier will operate colder and with
strong and well controlled bass.
The conventional audio mosfets have an internal resistance 4 to 7 times
greater than the switching mosfets.
b) The fast operation of the mosfets gives both a treble transparency only
achieved by the valve amplifiers and a very low TIM (Transient Intermodulation
Distortion).
The models PAM 4100 and 6100 feature “N-channel” SPM Technology, which makes
use of N-channel Mosfets for very high output power. This new technology has
proven extremely well in our industrial sound system “enviro” for obtaining
very high output power without the need for bridged configurations.
Main features:
“All the power All the time” philosophy, even at maximum output power and on
4W with musical programme.
“Back to Front” cooling system takes air from the rear and throws it out at
the front panel.
Effective protection systems that do not affect audio quality with anticlip
system and status indicators. Auto reset system. Soft start feature.
The models 4100 and 6100 feature A2SP (Analogue Autogain Signal Processor), an
VCA-controlled autogain protection system and intelligent variable threshold
anticlip protection that adapts to the incoming type of transitory.
Switchable subsonic filter.
The models 4100 and 6100 feature a dual power supply.
Thermal management system. Temperature controlled progressive cooling.
Road-proof, robust chassis.
Lockable gain controls.
INSTALLATION
3.1. Placement, mounting, cooling
The PAM1100 and 2100 models are presented as a 19” rack module of 2 units
height, while the PAM4100/6100 models are presented as a 19” rack module of 3
units height.
The amplifier must not be completely enclosed and/or exposed to high
temperatures.
A path for cool air to the inlet of the forced air tunnel must be provided.
The air inlet is on the back of the amplifier and gets out on the front panel
thus avoiding an excessive heat accumulation when mounted in a rack and
extending the electrolytic capacitors life. It is also convenient to place the
amplifiers on top of other equipment and not under it when mounted in a rack.
In all models, the cooling air flow increases as a function of the amplifier
internal temperature thanks to the progressive cooling system.
Four plastic washers are supplied to protect the fixing profile when the
amplifier is mounted in a rack. It is also advisable to use fixing guides on
the sides of the rack for a better security of the amplifier, specially when
transport can be frequent.
The models 4100 and 6100 include a handle set to ease the transport and
mounting. (See figure 1)
3.2. Mains connection
All the models can be supplied for 110-120 / 220-240VAC and 50-60Hz, depending on the country (see characteristic label on the amplifier), being the approximate power consumption at full power:
Contact our Technical Services whenever a supply voltage change should be
needed.
WARNING!: By convention, the mains wire colour assignment is the following:
The PAM2100/4100/6100 models have been provided with a soft start that limits
the current peak when starting up the amplifier to a maximum of 25A. This
system enables the simultaneous connection of various amplifiers without
overloading the magneto-thermal switches and also increases the electronics
reliability thanks to the suppression of the initial transitories.
The PAM1100 do not need this system because of their lower power.
Make sure that the mains wire is not engaged with the signal wires in order to
avoid possible hum.
A set of slow blow fuses on each power module, on the transformer primary and on the soft start circuitry (see table) is disposed in the amplifier as a protection against overloads. Whenever one of this fuses blows, it must be replaced by another one of the same characteristics. If it blows again, please consult our Technical Service.
CAUTION: Fuse substitutions have to be performed by a qualified technician.
3.3. “Earth Link” switch
The Earth Link or Ground Link switch (12) prevents possible ground loops when
various machines in the same chain are connected to earth. This switch makes
possible to disconnect the electrical ground from the mechanical ground.
Whenever hum arises, alternatively switch the earth link switches of the
amplifier and others components of the audio chain.
3.4. Input signal connections
The signal input connectors are of XLR-3 type (16), electronically balanced.
The pin assignment is as follows:
- GROUND
- PHASE (signal in phase with the output)
- NON PHASE (signal in opposite phase with the output)
The input connections for a balanced or unbalanced sound signal are as Fig. 2.
The “STK OUT” outputs (15) are in parallel with the inputs and are used to supply the same input signal to other amplifiers or sound systems. The input impedance is 20KW (balanced) with a nominal input sensitivity of 1V (0dBV). This impedance makes possible to parallel several amplifiers without loosing audio quality.
The input circuit has an electronic protection against overloads of 80Vpp (permanent) and 250Vpp (short moments). There is an RLC radiofrequency filter that avoids possible intermodulation’s and also protects the treble loudspeakers. The rising time of the input signal has been optimized for a very low TIM.
3.5. Output connections
The “OUTPUT” section on the back panel is provided with Speak-on connectors
(9).
To operate the amplifier on BRIDGED mode, place the “STEREO BRIDGE” switch
(13) to the “BRIDGE” position. The correspondent Led on the front panel will
shine. The input signal must be connected to the channel I connector while the
output signal will be present on the Speak-on connector labelled as “BRIDGED”.
The phase shifter used for BRIDGED mode is electronic and is placed in the input circuit, thus lessening the distortion and increasing the phase margin. When operating on BRIDGED mode, the signal input is made through channel I input and the corresponding input attenuator is operative while the one of the other channel is not.
The cable between the amplifier outputs and the loudspeakers must be of good quality, enough section and as short as possible. This is very important when the distance is long and the load is low (4-8W). We recommend a section of 2.5mm2 or more for distances up to 10m and a section of 4 or 6mm2 for longer distances. An easy way to known the required section, assuming a 4% loss, is:
3.6. Subsonic filter
This filter cuts off inaudible frequency components which when amplified
suppose a risk of damage to the low frequency speakers as they generate
excessive excursions of the woofer’s diaphragm. The filter, which has a
Butterworth shaped response with 18 dB/oct slope can be internally set to
three different cut-off frequencies or switched off completely (20, 30, 40 Hz
and OFF). The amplifiers are delivered with a cut-off frequency of 20 Hz. To
select a different cut-off frequency, refer to figure 3.
OPERATION
4.1. Starting up
To start up the amplifier, turn on the ‘POWER’ switch (7). It will light up
together with the two red ‘PROTECT’ leds (3). After a short while, the
voltages will have stabilised and the PROTECT leds will go off.
During this period, the A2SP (Analogue Autogain Signal Processor)
progressively (in about 300ms) raises the amplifiers input gain (models 4100
and 6100)
It is very important to start the audio chain in the following order: sound
signals, mixer, equalizers or active filters and, finally, power amplifiers.
To stop the chain follow the inverse order.
4.2 Input attenuators
These are based on rotative potentiometers placed on the front panel (1). The
attenuators make possible to use loudspeakers of less power than the amplifier
in a safe way, without damaging them by a misuse of the preamplifier and/or
mixer volume. The amplifier is supplied with two transparent plastic caps that
let you lock the Input gain controls. Once inserted they can only be removed
with a sharp object.
4.3. Protections / Status indicators
All models feature a non-destructive protection system, leaving audio quality
unaffected.
The high output power models PAM4100 and 6100 additionally feature the A2SP –
System (Analogue Autogain Signal Processor), that consists in an VCA (Voltage
controlled Amplifier) controlling the Input Signal gain in high stress
situations at very low load impedances (2W or lower). As opposed to
conventional compression or limiting techniques, the side-effects are not
noticeable and most important, neither dynamic range is reduced nor THD is
increased. Furthermore, these models include a thermal sensor inside the
transformer that also contributes in controlling the A2SP in case of reaching
a critical temperature that could be dangerous to any of the two power
transformers.
Anticlip circuit: This system is an always active protection which constantly analyses harmonic distortion caused by excessive signal excursion at the power amplifier’s output and automatically reduces the input level in order never to exceed 4 % total harmonic distortion, which is the default setting. Models 1100 and 2100 can be adjusted via an internal jumper to a stricter limiting (THD 1%). See figure 4.
The convenience of such a circuit in any kind of installation has to be remarked: The clear advantage of a limiting system in front of conventional compressors is that the former does practically not alter the dynamic range, acting only when the distortion threshold is reached.
On the models 4100 and 6100 the anticlip system is “intelligent”, as it acts differently depending on the transient type. For transients shorter than 150 ms, it limits so that 10% THD is allowed, while for transients longer than 150 ms, a maximum THD of 0.1% is allowed.
4.3.a) Signal presence indicators “SIGNAL” (5)
They show the presence of a signal at the amplifier inputs. They shine when
the input level is greater than -40dBV.
4.3.b) Protection indicators “PROTECT” (3)
Besides lighting up during stand-by mode (when switching on the unit), these
indicators will light up for following reasons:
- Because there is a short-circuit at the amplifier output. In case of a permanent short-circuit, the protections will disconnect the amplifier in less than 70ms (Models 1100 and 2100); models 4100 and 6100 continuously protect and disconnect in 15s. The protections also become active when there exists an excessive high frequency clipping, thus protecting the tweeters
- If the amplifier is supplying DC signal or very low frequencies that could damage the loudspeaker. The protections detect frequencies under 4Hz. A CROW BAR system is used to separate the loudspeakers from the output terminals.
If the indicators are permanently lit, this is a symptom of malfunction and the cause should be investigated.
The Autoreset system will cyclically restart the amplifier after about 15-18 seconds.
If the problem still persists, please consult our Technical Services.
4.3.c) Clipping indicators “CLIP” (2)
They will shine when the output signal is 0.3dB under the true clipping. This
system takes into account the possible changes of the mains supply and always
gives a true measure independently of the mains voltage. It is usual that the
CLIP indicators shine following the bass frequencies when the amplifier
operates at high power levels. Take care that the CLIP indicators are not
permanently lit.
4.3.d) “MONO BRIDGED” indicator (6)
It shines when the back panel “STEREO BRIDGE” switch is placed on the BRIDGE
position.
4.3.e) Thermal protection indicator “THERMAL” (4)
It shines when the cooling tunnel temperature reaches 90ºC. The amplifier will
automatically restart when the temperature lessens to 80ºC.
4.4. Operation at 2Ω
Operation at 2Ω considerably reduces the sound quality and the system
efficiency; e.g., the loss on the loudspeaker cable reduces the Damping Factor
by a 76% because of operating at 2Ω instead of 8Ω.
Almost all the amplifiers in the market base their operation at 2Ω on the use
of destructive protections to keep the components safe, with the penalty of
sound quality. Also, and for both technological and power supply reasons, the
power gain involved in operation at 2W instead of 4Ω is usually very low.
The SPM ECLER and SPM CHANNEL N amplifiers are able to operate at 2Ω keeping
its philosophy of non destructive protections and delivering every Watt the
power supply is capable of. The only limitation is the thermal protection and
the A2SP system in the CHANNEL N models, which would only get active after a
long period of operation at high power or a saturation of the cooling system.
This would cause an automatic and progressive reduction of the input gain
without affecting musical dynamics nor limiting transient signal peaks.
ECLER, following the maximum sound quality criterion, recommend using the 2Ω
connections only in installations where the amplifier will operate far from
its maximum power.
ACCESSORIES
5.1. Active Filters
All SPM ECLER and SPM CHANNEL N professional amplifiers (PAM 1100, 2100, 4100,
6100) can incorporate an optional active filter module, thus greatly
simplifying bi-amplified installations. This module is common to both channels
(stereo) and can be configured as low-pass or high-pass Butterworth filters
with a slope of 18dB/octave.
The FA2LP low-pass filter can be configured for 4 different cut-off
frequencies: 100, 125, 150 and 200Hz. The selection is made by means of
“jumpers”.
The FA2HP high-pass filter has the same cut-off frequencies and the selection
is also made by “jumpers”.
Refer to the enclosed module manual when installing the filter.
CLEANING
The front panel should not be cleaned with dissolvent or abrasive substances because silk-printing could be damaged. To clean it, use a soft cloth slightly wet with water and neutral liquid soap; dry it with a clean cloth. Be careful that water never gets into the amplifier through the holes of the front panel.
DIAGRAMS. 7.1. Figures
7.2. PAM1100/2100 Block diagram
7.3. PAM4100/6100 Block diagram
7.4. Function list
- Input attenuator
- Clip indicator, CLIP
- Protection indicator, PROTECT
- Heat protection indicator, THERMAL
- Signal present indicator, SIGNAL
- Bridged mode indicator, BRIDGED
- Illuminated mains switch
- Fan
- Speak-on connectors to the loudspeakers
- Fuse holder
- Mains cable
- Switch to disconnect chassis earth/electrical ground, GND LINK
- Bridge/mono selector switch
- Earth terminal, GND
- XLR output connector to other amplifiers, STK OUT
- XLR input connector, INPUT
7.5. Function diagram
TECHNICAL CHARACTERISTICS
(*) Both channels operating. Peak power: one channel operating.
References
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