4
INTRODUCING THE AUT 2000 STEP-UP TRANSFORMER
The AUT 2000 is Allnic Audio’s Step-up Transformer.
Like all Allnic Audio products, it uses Permalloy (iron
and nickel alloy) for its transformer (step-up) cores.
Allnic is grateful to Mr. G.W. Elmen of Western
Electric for inventing Permalloy for transformer core
use, and in so doing, providing an enormous service
to recorded music listeners everywhere.
The AUT 2000 has the following features:
•
Different brands and models of phono stage
pre-amplifiers apply different voltage gains. In
order to cope effectively with the multiplicity of
system environments created by these
variations in voltage gain from phono stage to
phono stage, a step-up transformer intended
for general use should be gain selectable
without, of course, compromising sound
quality. The AUT-2000 Step-up Transformer
features gain selectivity, an excellent square
wave response over a broad frequency range,
and an extremely low noise level.
Conventional gain selectable step-up
transformers provide voltage gain selectivity by
using several primary windings connected to an
external selector switch (Fig. 1).
Figure 1 - Conventional Gain Selectable Step-up
Transformer
Allnic Audio takes a different approach. The
AUT-2000 is built with both the transformer and
the selector switch embedded within a single
block of mu-metal shielded casing (Fig. 2).
Figure 2 - Gain Selection of Allnic AUT-2000
Because the Allnic AUT-2000 is precisely
machined from a solid aluminum alloy block,
mechanical vibration in the unit is greatly
reduced. In addition, the spaces between the
transformers and the unit’s body are filled with
a silicone elastomer that possesses excellent
vibration attenuation characteristics.
The Allnic AUT-2000's unique structure
significantly reduces the length of the signal
path and substantially improves the signal to
noise (S/N) ratio.
•
The Allnic AUT-2000 has an exceptionally flat
signal response across a broad frequency
range, using a secondary load resistor at 47
kOhms, as installed for MM cartridges in phono
stage circuitry. (Allnic does not manipulate
lower valued resistors to produce a flatter
response curve). The following table indicates
the signal response at each of the AUT 2000’s
gain levels.
Gain Level
Frequency Range Signal Response
+22 dB Gain
(x10)
20 Hz - 20 kHz
0 dB, 0 dB
+26 dB Gain
(x15)
20 Hz - 20 kHz
-0.2 dB, -0.2 dB
+28 dB Gain
(x20)
20 Hz - 20 kHz
-0.6 dB, -0.6 dB
+32 dB Gain
(x30)
20 Hz - 20 kHz
-1.5 dB, -1.5 dB
Signal Response at each Gain Level
Measured by Tektronix CFG 253 Oscillator,
Leader LMV-189AR AC Voltmeter
•
The large nickel Permalloy cores in the
transformers result in high input voltage
saturation and, consequently, very deep bass
reproduction.
•
The Allnic AUT-2000 is equipped with a
separate gain selector for each channel. This
eliminates channel crosstalk from the unit.
•
Provision of lower gain levels helps to
accommodate the current ever growing number
of high output MC cartridges.
