Integrated amplifiers

  • Technical characteristics
    • Output power: 120W RMS on 8ohm
    • 200W RMS on 4ohm
    • 350W RMS on 2ohm
    • Pre stage: Pure A Class
    • ECC83/12AX7
    • zero feedback
    • Power stage: Dynamic A Class
    • POWER BJTs
    • Inputs: 4 line unbalanced
      1 line balanced
    • Line Outputs: 1 tape
      1 sub (volume controlled)
    • Outputs connectors: 4 + 4 for bi-wiring
    • Feedback factor: zero
    • Power consumption: 1000W max
    • Dimensions: 17.1in x 5.1in x 17in
    • Net weight: 55lbs
  • Downloads
  • Audio Review

You might be saying to yourself, “Another Unico? Really?” We’ve even had people complain to us that since Unico means “one,” we shouldn’t have so many Unicos in the Unison Research product line! But the simple fact is that to us, “Unico” also means “unique,” and there are no other electronics that come close to the performance, value, features and beauty of the Unico line. This is why we’re proud to introduce this newly-born Unison Research amplifier and to call it, once again, a Unico.
It seems that every new product that enters the marketplace is deemed “revolutionary,” and we’re not just talking about the hi-fi market. Every designer and manufacturer claims that the latest product introduction truly re-defines what is possible. But we are here to say that the Unico50 integrated amplifier is truly revolutionary, and this is far more than mere rhetoric.
When we designed the Unico50, our Unison Research technical staff wanted to create much more than just another integrated amplifier. We wanted to set a new course for amplifier design in the 21st century. We’ll start with the most obvious innovations, and save the best for last.

First of all, the Unico50 is a powerful stereo integrated amplifier that fits into a relatively compact chassis. It integrates perfectly into the latest generation of high-level Unico designs and even shares the same dimensions as the UnicoCDE and UnicoPRE. That means the Unico50 looks substantial and authoritative while still maintaining a well-proportioned and appealing look that’s easy to integrate into any type of environment.

Our design staff wasn’t scared off by the challenge of combining aesthetics and technical sophistication. First, they took the cumbersome, oversized heatsinks found in most powerful amplifiers and transformed them into distinctive black anodized side panels that are perfectly integrated into the chassis. This design increases the overall strength and sturdiness of the Unico50 chassis.

In addition, this impression of power, grace and beauty is reinforced when you pick up the Unico50 for the first time. It’s nearly as heavy as its big brother, the Unico100. This feeling of unbridled strength and finesse is further enhanced when you touch the solid aluminum knobs on the front panel for the first time. These knobs drive a couple of heavy-duty rotary encoders from ALPS which have been selected by our design team for their reliability as well as their precise and firm operation.
Once you look inside the Unico50, you’ll immediately notice how clean and organized the design is. You’ll also notice the highest quality parts. But it’s the actual design of the circuitry, not obvious to the casual observer, that makes the Unico50 so unique.
First, we’ve included a refined version of the digitally-controlled volume control that we first used in the Unico100. Thanks to our new integrated circuitry, the allowed input signal swing is increased to around 27 V peak-to-peak and fully protected from voltage spikes. As in the previous design used in the Unico100, every input is treated as a balanced signal, preventing ground loop and noise that can be generated through the cable connections.
The Unico50 is a hybrid amplifier, as per the Unison Research tradition. The tubes we use in the Unico50 are the well-known ECC82/12AU7s, pure Class-A biased, with precisely regulated heat and high anodic voltage. But in this new design, the preamplifier stage is an independent circuit working as a stand-alone tube preamplifier. There’s no feedback from the power output to the input stage, therefore leading to a zero global feedback design! There is also no feedback from the output of the preamp stage. The couple of triodes in the tube are arranged respectively as a common cathode gain stage followed by a cathode follower low impedance output stage.

The following driver stage is derived from a well-known and time-tested topology designed by Unison Research. But since our technical staff is never tired of going just a little bit further with a design, they offered additional refinements that increase the inner input impedance, thereby offering a better load to the preamp stage. In this configuration, the interface parameters are the same as when you match a stand-alone preamplifier to a power amp.

Another revolutionary feature involves the power stage design: you won’t find any power
MOSFETs, but you will find power BJTs. The bias control has been tested and refined by Unison Research for many years with great success; it’s a proprietary design that drives a couple of medium-power MOSFETs in order to offer the best input impedance to the driver stage, ensuring high bandwidth and great dynamics. These are followed by a couple of medium-power BJTs driving the power stage: four high current audio bipolar transistors are arranged in a mixed npn-pnp configuration.

The BJTs employed are specifically designed for audio and exhibit high current capability and great reliability. A thermally-enhanced package, in conjunction with special thermal conductive insulation pads, makes them the perfect choice for such a demanding design. In order to reduce distortion introduced by inevitable dissymmetry of different devices, even if the measurements matched, we adopted a different approach by designing an uncommon topology that ensures perfect equality between the positive and negative side of the power stage mixing npn and pnp devices.

Such a refined design can only express its true potential if supported by an adequate
power supply. Our no-compromise design required a complete dual power layout. Both left
and right channels are powered by their own toroidal transformer (a 500VA custom-designed massive transformer) and an independent capacitor energy storage of 40000uF which is placed as close as possible to the power devices. For the Unico50, we use the same power transformers
and capacitors (respectively 1000VA and more than 80000uF) that are used in the Unico100. This ensures incredible current capability and therefore fast, dynamic and precise control of every loudspeaker that is used.

The Unico50 is a truly revolutionary addition to the Unico series. This new amplifier preserves all of the qualities that made the Unico series one of the most elite product lines in the world, and yet it pushes the boundaries even further by renewing the promise of an utterly exciting listening experience.