The Model Compact 845 that you chose is an integrated amplifier in pure class “A” which enhances the last technical evolution of the famous triode 845. The output transformer we designed and manufactured for this triode allows a range of extension which would be otherwise impossible with the use of standard output transformers which need work with a negative reaction. Our new pre-amp section, of the Compact 845, grew from our careful research. Combined with our unique output transformer and powerful, 845 triodes working in Single Ended mode, the amplifier renders a genuinely engaging sound. We use a semiautomatic biasing system, which once regulated, will give optimal life to the final tubes. Finally, we use 24 karat gold connections on the Compact 845 circuit board. The capacitors are manufactured with high quality for our product. The result is a perfect sound stage and a surprising presence. We produce amplifiers that arouse emotion, in which every note of music should precisely reflect the emotions of the composer and the performer. In addition to the technical excellence, our amplifiers satisfy the ultimate search for the life-like performance. Therefore, not only a perfect soundstage, focus, and dynamics are involved, but also a "spirit" quite rare in many systems - blend into the total synergy of your system. The listeners feel immersed in the music and carried away through enjoying the life-like details of the instruments, in the most natural means possible... with emotion. Mastersound amplifiers, except the tubes, comes with a five-year limited warranty covering defects in material and craftsmanship. During the warranty period, repairs are provided free of charge.