Electrocompaniet ECI2 User Manual
ECI 2
HIGH CURRENTINTEGRATED AMPLIFIER
Owner’s Manual
W ARNING: To reduce risk of fire or electric shock, do not e xpose this appliance to rain
or moisture. Verify line voltage before use.
Do not remove cover. No user serviceable parts inside. Refer servicing to qualified
service personnel. The warranty in void if the product is tampered with by non
authorised personnel. Use only authorised Electrocompaniet service station.
Welcome to the world of Electrocompaniet
We sincerely thank you for selecting an amplifier from Electrocompaniet. We hope you will
enjoy years of listening pleasure and true high end musical performance from your audio
system. Kindly read this owners manual to familiarise yourself with the set before
operation.
The Electrocompaniet Story
Electrocompaniet was founded in 1973 in Oslo, Norway, to manufacture an amplifier
designed by Per Abrahamsen. The design were based upon a new approach to transistor
amplifier design developed by Dr. Matti Otala and Jan Lohstro.
It had long been recognised that transistor amplifiers had a characteristic sound that many
audiophiles and music lovers found unnatural.
Dr. Otala and Mr. Lohstro analysed transistor amplifiers to determine what actually created
the “transistor sound” in general transistorised designs. The results of their innovative
design work were incorporated in the first Electrocompaniet design, the legendary 25 watt
amplifier.
This product were the first commercial transistor amplifier to use this new design
approach, and the amplifier was immediately recognised as dramatically more musical
sounding than any other transistor amplifier. The same design philosophy, has been
constantly updated by additional research and development. This philosophy form the
basis of all the current Electrocompaniet Ampliwire and Preampliwire Dual Mono
Balanced designs.
Electrocompaniet have always given extensive listening test of all it’s designs the highest
priority. Every product designed by our engineers must meet the varied and exacting
standards of the listening panel, carefully selected to represent a cross section of musical
taste and experience. Electrocompaniet designs go back and forth between the design
laboratory and the listening panel until both engineers and listeners are completely
satisfied, and ensured the that the design has met it’s technical and sonic objectives.
All Electrocompaniet products are handmade by highly skilled technicians, and
extensively tested for maximum performance and reliability.
Final adjustments are made only after an extended period of operation to insure the best
possible performance under conditions similar to those of actual use.
Electrocompaniet Ampliwire and Preampliwire are sold in more than 25 countries ,
providing the ultimate listening pleasure to dedicated music lovers world-wide.
The design features of Ampliwire ECI 2
After the Electrocompaniet 25 watt amplifier had established a new standard for transistor
amplifiers, research was undertaken to find ways to make the amplifier even better, and to
extend its highly musical sound quality to more powerful amplifier designs. The engineers
at Electrocompaniet were not satisfied by only reducing the commonly recognised types of
distortion to low levels. They recognised that distortion appears in many forms, and that
distortion was still audible in listening tests even When conventional categories of distortion were at astonishingly low levels.
Traditionally, designers increased feedback to make a larger portion of the output signal
control the amplifiers response. Our listening tests showed us that simply applying more
feedback was not the answer. In fact, as one kind of distortion went down, other parameters
would be adversely affected, leading to an overall degradation of sound quality. We knew
that the other conventional design approach of eliminating feedback completely was not
the answer either, because this would cause high distor tion levels, and as a result would
produce a “woolly” sound.
The answer to the dilemma was found in a novel approach to feedback theory. We
developed a feedback concept that allowed local feedback to be applied around individual
stages of the amplifier circuit. This approach allowed us to avoid the sonic disadvantages
of overall feedback from output to input. The concept was further developed to reduce
phase- and interphase distortion between stages of the amplifier as well. We were able to
concentrate the loop feedback on the stages of the amplifier where it resulted in audible
improvement.
Stability margins were also expanded because feedback no longer affected the frequency
response. The use of this concept of individual gain blocks - complex in design but simple
in function - allowed us to reduce distortion to minute values in all the products.
The amplifier is divided into two separate sections or gain blocks. The input block is a
transconductance amplifier without overall feedback. This avoids large output current
being fed back to the input, and mixed with the minute input signal. The output block is a
transresistance amplifier with parallel feedback. This is done to prevent higher frequencies
than the feedback loop can handle, from entering the loop. An approach like this will
prevent Transient Inter modulation Distortion (TIM) and Slewing Induced Distortion (SID),
eliminating the need for an extremely wide bandwidth.
All stages work in Class A with an efficiency of less than 0,1%. The power supply of the
ECI 2 consists of a 550 VA toroidal transformer. Fur thermore, the power supply consists of
a 26.000 micro farad reservoir divided into two 10.000 micro farad in parallel with six 1000
micro farad capacitors.
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