Unison Research Unico Due integrated Amplifier with DAC and Phono

I have these very popular amps, brand new, in stock!

I also have one demo unit at a reduced price.

"I
just spent a few weeks listening to the new Dúe. This is a really great
amp. It is very involving, beautifully built and  approaches the sound
of the LFD amps. There is no doubt this amp is a bargain as it includes a
fine DAC and built in phono stage!"--Gene Rubin

PLEASE NOTE: Both the Phono and Dac are INCLUDED with the new DUE.

Unico
Due is the latest amplifier from Unison Research. Unico Due  benefits
from Unison Research’s decades of experience in design and  production
technology. It maintains all the best qualities that made its
 predecessor a runaway success and introduces new and enhanced features.

Circuit

The
electronic circuitry of the Unico Due has been completely  redesigned.
While maintaining the qualities that made the Unico range  such a legend
in the audio industry, key improvements have been made  that are
nothing short of ground-breaking. Firstly, the power supply  circuits
have been enhanced thanks to a substantial increase in
 filter capacitance size and to a new high quality shielded and
 encapsulated power transformer. The new power distribution system of
the  audio power output stage combines space optimization, superior
circuit  solutions and improved assembly and service solutions.

The
heart of the preamplifier stage in based around two ECC83 double
 triodes (one per channel), configured as a gain stage followed by a
 cathode-follower. This circuit’s low output impedance efficiently
drives  the power stage that follows. The final choice of the type of
valve and  the circuitry used was made following extensive listening
tests,  after we experimented many equally high performance valve-based
 solutions and configurations in our test laboratory.

Features

The Unico Due aims to satisfy even the most demanding users and offers the following features:

• One USB input to the Unico Due’s internal DSD 128 bit DAC.

• One direct analogue line output from the Unico Due’s internal DAC, which allows it to be used as a stand-alone DAC.

• A low impedance subwoofer output (SUB) with variable output level from the preamp for connection to an active subwoofer.

•
AV input that allows the Unico Due to be connected to a home  theatre
system: pressing the “push” button on remote control, the Unico  Due
will automatically select the chosen channel at a user-configured
 volume level.

• Dynamic Class A
power amplifier biasing where the power transistors  never turn
off completely. This provides excellent sound results even  at low
volume.

The Unico Due offers
four inputs: three analogue inputs and one USB  digital input. The input
selection uses sealed miniature relay switches  to preserve the
delicate low-level signals, whereas the volume  regulation is based on
an integrated high-precision,  high-performance resistor array followed
by a set of digitally  controllable analogue switches, used in reference
products and capable  of 120 dB of attenuation with 0.5dB steps. The
power output stages are  solid state and use a completely original
combination of bipolar and  MOSFET transistors. Furthermore, instead of
designing in  standard differential input stages, a sophisticated
symmetrical BJT  circuit is used that has moderate gain and very high
intrinsic  linearity, with separate feedback loops for AC and DC
signals.

Thanks to its low
distortion, we were able to configure it to have a  very mild
feedback level. The power output stages of the Unico Due  feature a
non-switching bias control circuit which prevents the current  in the
output transistors to reach zero. This greatly reduces distortion  at
low and very low listening levels and guarantees the highest
 sound transparency in any condition.

The
power output devices are connected in a “super symmetrical”
 configuration, i.e. negative and positive signal polarities are handled
 separately by a combination of N and P type devices.

You
may ask yourself why we should worry about minimizing the  distortion
of the solid state power output stages when there is a valve
 pre-amplifier section that will add a small amount of distortion. The
 reason is very simple: our goal was to create an integrated amplifier
 whose “sonic character” was mainly dominated by the valve section, but
 with enough power to comfortably drive any loudspeaker system.

To
improve performance further, we added regulated power supplies not
 only when it was absolutely necessary, but also in any part of the
 circuit where this would bring sonic improvements over using simple
 filtering. In the Unico Due there are no less than ten stabilized power
 supplies with output voltages ranging from 15V for low
 signal operational amplifiers to the 300V required by the valves in the
 preamplifier stage.

Particular
attention was paid to the output power stage supply.  Considering the
high value, impulsive, almost intractable nature of the  current that
the power stage has to handle, we decided to adopt a bold  solution. We
used large-value, high-quality capacitor banks, some of  which are
placed close to the power transistors to minimize the path to  the
current pulses. The supply tracks on the PCB are generously sized,
 having a thickness of 105um (3oz), and the ground return tracks have
 been designed with extreme care. Obviously difficult choices like these
 can create a number of design and realization difficulties which many
 engineers may decide to give up on and find easier solutions, but the
 engineers at Unison Research embraced these challenges and solved them
 without compromising on quality and performance. The final result is a
 design where almost 25% of the entire surface of all the PCBs in the
 Unico Due is dedicated to supplying power to the output devices!

The
same meticulous attention was paid to managing the low-level  audio
signal. Starting with the gold-plated input connectors, to the  speaker
sockets that are also gold-plated, robust, versatile and  completely
insulated according to the latest regulations. Furthermore,  the audio
signal is fed through circuitry using the highest available  quality
of components: high-precision sealed micro-relay  switches, carefully
selected Mundorf capacitors, low tolerance  metal film resistors,
ceramic tube sockets with gold contacts, and much  more.

USER INTERFACE

INPUT SELECTION

You
can select the input source by rotating the “selector” knob or
 pressing the dedicated buttons on the remote handset. The selection
 sequence is circular; the currently selected input is indicated by the
 front panel LEDs.

VOLUME SELECTION

The
volume setting can be varied by rotating the “volume” knob or  pressing
the dedicated buttons on the remote handset; the level is  indicated by
the front panel display which shows a number between 0.0  (min level)
and 9.9 (max level).

TAPE/MONITOR MODE

Switching
to tape/monitor mode makes another line-level input  available (see
Notes about inputs); you can activate it with a short  press on the
selector knob. Another short press switches it back to the  selected
input.

MUTE

The
mute function immediately applies the maximum attenuation to the
 currently selected input. You can activate it by a short press on the
 volume knob; the level shown on the display doesn’t change but the mute
 status is indicated by the status LEDs. Another short press disengages
 mute.

OSD

The
OSD function puts only the output power stages in stand-by mode.  When
switched back, the devices starts without requiring warm up. The  DAC
line output remains active.

DISPLAY OFF

When
the display is set to off, the display turns off after 20  seconds of
inactivity and turns on automatically when any single  function is
activated.

BALANCE

Hold
the volume knob pressed for a few seconds to adjust the channel
 balance; thedisplay will then show the balance level: the first digit
 indicates the level of the left channel, the second digit indicates the
 level of the right channel; turning the knob adjusts the balance
level.

AV MODE

The AV function allows you to connect Unico Due to an AV playback system and you can

choose the AV input and pre-set the volume level. Once set, pressing the "Push" button

on the Unico Due handset will switch to the AV input selected and adjust the volume to

the previously pre-set level.

SETTING AV MODE

Select
the desired channel and volume using the input and volume  selector
knobs. Hold down the selector switch on the monitor, press the  OSD
button until the display flashes, then release the button.

Pressing
the "push" button on the Unico Due remote control will  automatically
switch to the selected channel on the selected volume.

DISABLE AV FUNCTION

• Put Unico Due into mute with a short press of the volume knob;

• Hold down the input selector knob to activate the monitor function, then press the OSD button until the display blinks;

• Release the button; after this, pressing the “Push” button on the handset will not do anything.

POWER PROTECTION

Unico
Due is equipped with a sophisticated microprocessor-controlled  system
that monitors its power output. In case the power output is high  over
an excessively long time, Unico Due gradually decreases the volume
 level to a more sustainable level to protect the power devices.

Technical Specifications:

Output power: 100+100W RMS into 8 Ohms, 180+180W RMS into 4

Ohms, 290W+290W RMS into 2 Ohms

Filter capacitance: 80,000uF

Output stage: Dynamic Class A power BJT double complementary

pair, “Super-Symmetric” configuration

Biasing: Dynamic Class A

Valves: 2 x ECC83 (12AX7)

Inputs: 3 analogue line (RCA), 1 digital (USB), 1 tape RCA

Analogue line Outputs: 1 tape (RCA), 1 stereo subwoofer (RCA), 1 DAC

Speaker output connectors: 4 + 4 to allow for Bi-Wiring

Dimensions: 43.5 x 43 x 13 cm (W x D x H)