Electrocompaniet EC4.6 User Manual

EC 4.6 REMOTE CONTROLLED

BALANCED LINE PREAMPLIFIER

Owner’s Manual

WARNING: To reduce risk of fire or electric shock, do not expose this appliance to rain or m oisture. Verify
line voltage before use.
Do not remove cover. No user serviceable parts inside. Refer ser vicing to qualified
service personnel. The warr anty in void if the product is tampered with b y 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 Preampliwire EC4.6

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 distortion 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 phase­and interphase distor tion 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 various amplifier stages are divided into two separate sections or gain blocks. The input
block is a transconductance amplifier without overall feedback. This avoids large output
voltage 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
EC-4.6 consists of a 50 VA toroidal transformers , and 10.000 micro farad reservoir divided
into ten 1000 micro farad capacitors, with separate regulator for each stage and channel.