Derived from the PHL5, the Spettro expresses the pinnacle of tube preamplification. No type of integrated circuit is used inside; everything has been designed perfectly. Inside the Spettro are a pair of parallel preamplifiers per channel (Dual Drive System) to halve the output impedance and, therefore, obtain an audio signal of astonishing speed and dynamics. The final amplifiers driven by this preamplifier can genuinely express their full potential. There are seven double triodes between the phono stage and the line stage, and all the components are highly selected and tailor-made. The power transformer was designed and manufactured in MastersounD's laboratories. The latest edition contains all the improvements made to the circuit over the years, with a new PCB board and an analogue signal filtering system allowing for greater signal cleanliness and transparency.