Audio Analogue Maestro Anniversary

Anniversary Line designed by AIRTECH - Amplifier

The Maestro Anniversary was born in the AIRTECH laboratories and is the result of the experience gained in the development of the Puccini Anniversary. The basic schematics of these two models are very similar, with one significant difference: the Maestro's amplification circuit, which is totally symmetrical from the input stage to the power stage, becomes asymmetrical in the connection with the loudspeakers. This led to the doubling of the amplification and attenuation stages (potentiometers). Similarly, all the stages of the Maestro Anniversary have been designed without global feedback, not even on the pre-amplification stage (and this is also the case on the Puccini). Output power has been increased to 150 W at 8Ω, with a consequent impact on the sizing of all complementary and power stages, which now feature two pairs of transistors per channel. The basic configuration is an inverted cascode, similar to a single gain stage followed by an output buffer. Operating point stability is ensured by a DC servo relay that only intervenes at frequencies below a few tens of Hz (i.e. well below the audible spectrum). Improved circuitry and the choice of top-quality components (military-standard resistors, audiophile-quality polypropylene capacitors designed for AIRTECH, OCC 7N copper internal wiring and pure copper output sockets) have resulted in an amplifier that has the honor of succeeding the superb Maestro integrated units. In fact, it completes the Anniversary range celebrating the twentieth anniversary ofAudio Analogue 's existence, as well as the 15th anniversary of the release of the very first AUDIO ANALOGUE device, named Maestro. The new Maestro Anniversary is an exclusive amplifier, with its remarkable power output doubled when the impedance is halved, and its extraordinary ability to handle complex loads, combined with an extreme musicality and refinement not usually found in the world of "muscular" amplifiers. Alas, words are not enough to express all the assets and specificities of this device, which is why we invite you to come and listen to it as soon as possible, the only way to check for yourself and exclaim: "MUSIC, MAESTRO!!!".

Technical description

The entire amplifier has been designed on the principle of three well-separated sub-assemblies. 1. Power. The Maestro features a 600 VA transformer per channel. The rectifier bridge is made up of ultra-fast discrete diodes, each rated at 50 A. The filtering capacity is 16800 μF per branch, so that the total amplifier capacity reaches 67200μF. During start-up, the inrush current is limited by means of temperature-dependent resistors which, once the start-up process is complete, are switched off with respect to the signal circuits. 2. Amplifiers. There are two amplifiers (for the left and right channels), totally separated from each other for both ground and power stage connections, with no common links whatsoever. The microprocessor circuits for digital volume control are themselves optically isolated. This is therefore a double mono configuration. The copper tracks on the printed circuit boards are double-layered by comparison with the usual standards, to ensure the smooth flow of high currents. The layout of the PCB tracks has been carefully studied to optimize audio signal transfer and guarantee perfect symmetry between stages. 3. Preamplification. As with the power section, the preamplification circuits are also double-mono. Just downstream of the input sockets are the channel switching relays, followed by a discrete component buffer to isolate the amplifier from the source. Maximum input voltage is 6 V RMS. The buffers, symmetrical for their inputs and outputs, have been sized to supply Class A power to the four microprocessors (per channel) controlling the volume. As with the Puccini, this is simply a resistor bridge, without any operational amplifier. This avoids the need for feedback on the Maestro's circuits. Downstream of this volume control stage is the preamplifier itself, which can amplify the signal up to 12dB. As the three sub-assemblies described above are arranged on separate printed circuit boards, this corresponds to having a separate power supply, preamplifier and power amplifier.