Electrocompaniet ECI1 User Manual
ECI1 DUAL MONO
INTEGRATED AMPLIFIER
Owner’s Manual
WARNING: To reduce risk of fire or electric shock, do not expose this
appliance to rain or moisture. Verify line voltage before use.
Do not remove cover. No user serviceable parts inside. Refer servicing to qualified ser vice
personnel. The warranty in void if the product is tampered with by non author ised
personnel. Use only authorised Electrocompaniet ser vice 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 1
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 distor tion 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 distortion levels, and as a result would produce a “woolly” sound.
The answer to the dilemma was found in a novel approach to feedback theor y. 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 distor tion 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 1 consists of two 500 VA toroidal transformer. Fur thermore, the power
supply consists of a 40.000 micro farad reservoir divided into four 10.000 micro farad
capacitors in parallel with 4,7 and 0,1 micro farad polycarbonate- and polypropylene
capacitors.
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