ELECTROCOMPANIET AS
Electrocompaniet
MC-2
Moving Coil Interface
The Electrocompaniet MC-2 is a unique step-up device. It will
make extremely low output moving coil cartridges compatiole with
any preamp. There are basically two parts of the MC-2 design,
each contributing to what is theoretically an ideal moving
coil-amplification interface. It not only responds to the
dynamic impedance demands of moving coil cartridges when a
musical signal is introduced, but the design also gives special
consideration to the dramatic influences of noise and distortion
on the amplification of the extremely minute signal that comes
from a moving coil cartridge. The Electrocompaniet MC-2 provides
a more exact and complete moving coil-amplification interface
than high-gain preamps and voltage-gain step-up devices.
The first part of the moving-coil interface circuit design is
a current-sensing device. The interface senses the current
coming from the moving coil and automatically adjusts to its
impedance characteristics. It is a dynamic interface, and is
constantly adjusting to the demands of any moving-coil cartridge
as it responds to musical signals. Voltage-gain step-ups are
designed to operate with a nominal static impedance measured
under laboratory conditions that will provide the flattest
frequency response for a given moving-coil cartridge; however,
when an actual musical signal is introduced these devices tend
to "damp" full dynamic and frequency response. The dynamic
current-sensing capabilities of the Electrocompaniet MC-2 do
not "damp" cartridge performance as is the case with step-ups
that require cartridge loading with resistors.
The second part of the circuitry is a user-adjustable feedback
loop.
that will result in the lowest noise and distortion for a
particular moving-coil cartridge. The importance of eliminating
as much noise and distortion as possible at the crucial input
stage where the signal is very small was only recently
discovered. As a result of years of trial-and-error
experimenting with the effect of closed-loop feedback on sonic
performance, the designer of Electrocompaniet electronics found
that a relatively small amount of feedback in the first stage
of amplification results in far more dramatic sonic improvement
than larger amounts of feedback elsewhere in the signal path.
The appropriate setting provides the degree of feedback
Although there is only 6 db of feedback throughout the entire
range of the 16-setting potentiometer in each channel of the
MC-2,
adjustments of only one or two positions result in obvious
sonic differences. Most moving coil cartridges perform best
with settings between 0 and 7, with 0 representing the least
amount of feedback. The user may prefer that the dealership
preset the MC-2 according to Electrocompaniet•s recommendations,
or the user may want to experiment with the settings. The
potentiometers- that control the feedback loop in each channel
are readily accessible through openings on the bottom plate of
the device.
Electrocompaniet has experimented with a number of moving coil
cartridges with the MC-2 and has determined that the following
ranges are most suitable:
Koetsu 1-3
Dynavector 2-4
Asak 3-5
EMT 3-5
AC-2 4-6
Alpha-1 3-5
The exact setting within the recommended range is dependent upon
a number of variables such as the sonic character of other
components in the system and the acoustic interaction of the
listening environment.
In general, a setting that is too low results in audible
distortion. The listener can readily recognize that bass and
high frequencies are soft and lacking in dynamic impact. A
setting that is too high results in increased low-level
transistor noise. Bass will be very tight, but high frequencies
oegin to sound unnaturally hard and sharp. Finding the right
setting is a matter of starting with a low setting and increasing
feedback until the listener recognizes unnaturally hard and sharp
high frequencies. Turning each potentiometer back one or two
notches should result in an optimum amount of feedback where
noise and distortion are at a minimum.
Musical intruments and performers will become more focused on
an amazingly dimensional soundstage. Tonal quality is accurate
and natural. Many listeners have commented that the sense of
electronics in their audio systems actually seems to disappear,
and they are closer to the vitality of the performance as
captured on the source.
Mailing
address:
P.O.BOX
Tel:(02) 706410. Telex: 18225otegr. Bank: Den norske Creditbank 7104.05.06092
92,
l473Skdrer, Norway. Office
address:
Stremsveien 72, l473Skdrer, Norway
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