STATUS - SOLD

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The Unison Research Power 35 is a 2x 35 Watt class AB pushpull stereo end amplifier. It is the ideal combination with Feather One preamplifier. A great compromise between delicacy, power and practicality. Very musically satisfying. The Class-AB, self-biasing Power 35 power amplifier employs a pair of 12AX7s, each forming an input buffer and phase splitter that feeds a pair of EL-34 pentodes (which means four in total) running in push-pull mode (incidentally, this represents Unison's first attempt in push-pull design). Inside, a hefty output transformer helps in pushing the unit's weight to 35kg. Parts quality is top rate, with high-voltage reservoir capacitors and audiophile knick-knacks commonly seen in high-end country. A little light-hearted entertainment is provided through some simple instructions printed on top of the transformer enclosure. The unit is rated at 35 watts, with four and eight ohm taps at the rear for proper load selection.

A push-pull topology amplifier is characterised by a power stage in which active devices pairs work together amplifying separately the positive and the negative signal half waves. The output transformer, with its particular structure, reconstructs the amplified signal and makes it available at the output terminals. The main benefit of this topology is the possibility to design amplifiers which have a much higher power than their single-ended counterparts, using the same power valves in the output stage.

This advantage reflects in a better efficiency, which also means a significant reduction of the dissipated heat at the same power rate. Nonetheless the push-pull stages, because of to the simultaneous action of two different devices, needs a very careful design and set up to avoid the large distortion that always occurs when the amplification of the two half waves is not equal.

Specifications :
Power output....................................2x 35 Watt class AB
Input impedance...............................50 Kohm/47 pF.
Configuration....................................push-pull pentode.
Max power consumption...................150 Watts
Weight.............................................22 kg
Dimensions(w x d x h).......................26.5 x 46 x 19 cm

Miscellaneous :
Matching.........................................Unison Research Feather One Pre-Amplifier
Made in...........................................Italy
Condition.........................................8 / 10 (Decent condition)

Reviews :
http://sites.thestar.com.my/audio/story.asp?file=/1998/11/05unison