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Unison SR-1
Hybrid Integrated Amplifier






With SR1, the Unison Research design team at A.R.I.A. (Advanced Research In Audio), have chosen a hybrid design employing transistors as well as valves, aimed at providing high power in an amplifier worthy of our traditional sound quality.

- Electronic Characteristics -


The combination of a pure triode input stage with a powerful MOSFET output stage gives 80 watts of power without losing any of the pleasing natural sonic characteristics typical of a well-designed tube amplifier.

The electronic circuit design developed for SRI is especially original, and in some aspects indeed offers quite novel solutions. It is the result of a close collaboration between Unison Research and the applied electronics department of the University of Padua.

The output stage of SR1 is fully protected electronically. However, the audiophile may opt to override the protection circuit in order to obtain the very purest musical signal. The twin-triode valves used in SR1 are robust, inexpensive and easy to obtain. They need present no undue worries to music lovers more familiar with fully solid-state (transistor) amplifiers.

Triode valves were chosen for the input stage of the SR1 because they have the ability to reproduce a natural, transparent quality of sound and hence a more enjoyable listening experience.

All connections to both inputs and outputs are gold plated, which will ensure excellent electrical contacts over the lifetime of SR1. Moreover, there are neither relays nor fuses in the signal path, with clear benefits to sound quality. This is especially important in the output path to loudspeakers, where the presence of switching relays could over time cause a loss of signal quality due to deterioration in the contact surfaces.

The mains transformer, which in the time-honoured Unison Research tradition has been designed and handmade in our own workshops, and its associated bank of power supply capacitors, are of very generous proportions. Together they provide all the current that may be needed by the SRI even under extreme conditions of use.

SR1 provides visual indication of its status by means of an array of front-panel mounted LEDs. Various conditions such as valve pre-heating phase, input overdrive, intervention of protection circuits, or fault condition warnings, are clearly indicated by these LEDs.

Last but not least, SR1 is provided with a radio-wave remote control handset which allows easy regulation of volume from a distance of several metres.




- Appearance Characteristics -

As is tradition at Unison Research, the appearance design of our products is a matter of great importance and pride for us. By its own unique form and combination of valuable materials, each of our products is handcrafted to be pleasing to the eye, and each in its own way represents the skill, artistry and experience of our design team.

The valves are mounted on a curved heat reflecting surface fashioned from stainless steel. This ensures that the small amount of heat produced by the valves is radiated away from the amplifier. This reflector also acts as a focal point for the eye, telling the listener in no uncertain terms that the SRI is no ordinary solid state device, but a valve amplifier with a vocation for serious music reproduction.

The appearance parts are handmade from finest quality solid hardwoods, and finished with natural organic lacquers. The control knobs are stainless steel, precision made on numerically controlled machines for a high degree of accuracy and fine surface finish.





- Sonic Characteristics -

As usual, fine-tuning of the sound of the SR1 was carried out during several months of careful listening tests, using a great variety of source components and loudspeakers. One of the most important results of this process was the choice of a precise amount of negative feedback (only 8db) to employ in the final design.

- Specifications -

Output Power:  80w/ch/8.
Bandwidth:  2 Hz ~ 70 kHz, -1 db.
Input Impedance:  47 kOhm, 50 pF.
Damping factor:  >50.
Feedback factor:  8 db.
Overdrive Indicator:  THD >1%.
Mains Draw:  290W at full power.
Dimensions:  10.7" - 17.8" - 5.9".
Net Weight:  33.7 lbs.





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AllegroSound
−  Established 1973  −
"love what you listen with"
Los Angeles, California USA
Rick@AllegroSound.com


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AllegroSound
−  Established 1973  −
"love what you listen with"
Los Angeles, California USA
Rick@AllegroSound.com
telephone 323.960.5014

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design and original content ©AllegroSound, los angeles, usa. all rights reserved.