I’m sure, that like me, many of the audiophiles and music lovers can easily recall the Audio Analogue brand name. They’ve produces some of the iconic high-end audio electronics over the years. One of them is Puccini amplifier, that is still being produced two decades after the introduction of the initial model.
That alone is quite a statement in the era, where the urge of overcharging and rapid introduction of the new products became sort of an endless race. As fast forward as present times might seem, people are again starting to explore and cherish the products with heritage, history and when it comes to the high-end audio, with the notable sonic potency.
THE HERITAGE
Back in 1995, a small integrated amplifier was born. The initial goal was to bring a captivating and pleasant music experience to the music lovers and audiophiles. Audio Analogue never had never compromised on the technology involved, but back in time, the focus was more on the direct, listening experience, then on push forward highlighting of the technology involved.
But, now we’re living in the very 21st century, where technical merits are as important as the design and audio reproduction quality. Audio Analogue team understood this modern challenges and the new Puccini Anniversary was designed from ground up as the contemporary machine with the and highly technical “brain”, “musical” hearth. Audio Analogue set the goal to design the best Puccini ever, that will be not only a turning point in the brand’s history but will also set the ground stone and the firm path for the future.
The cooperation with Airtech Laboratories has led to the initiation of an integrated amplifier without global feedback. After months of evaluations and tests, the partnership with Airtech was consolidated and the development of this unique amplifier has reached the final stage.
NO FEEDBACK!?
Why no feedback? An engineer and Airtech designer Andrea Puccini explains:
“It’s simple. You have to test and verify the final result. In audio, there are no magic solutions that make an amplifier a great amp, you must experiment. This is what we said together with my colleagues in the R & D Airtech Team. We wondered then, what were the real advantages of feedback typically used in audio and we made to do list”…
They wanted to:
1. Increase the input impedance;
2. Decrease the output impedance;
3. Stabilise the gain;
4. Reduce the power supply disturbs;
5. Decrease the distortion, up to levels, that are almost not measurable;
6. Stabilise the working point.
There is always a juxtaposition of lab measurement and listening conclusions. So, while the highest possible measuring results are important, one can never neglect the audible part.
Let us dig deeper. Here is the breakdown of all the initial goals connected with the Puccini Anniversary integrated amplifier design:
Increasing of the input impedance
“In the audio impedances operates the order of a few tens of KOhm. With the Puccini Anniversary Audio Analogue has used a differential stage with a high gain transistor and (necessarily) “degeneration” resistor rather than high, what lets the input impedance with enough gestalt.
Decreasing the output impedance
Audio Analogue team felt how the importance of output impedance is to often overlooked, but the Puccini Anniversary uses three pairs of power transistors, that brings resistance of about 0.2 ÷ 0,3Ω (therefore a damping factor of between 27 and 40).
Stabilisation of the gain
Power amplifiers with feedback gain are dependable only by the feedback network, that allows the operating stability. On contrary Puccini Anniversary integrated amplifier implements a differential stage, that converts the input signal from voltage to current using a degeneration resistance, high enough to reduce the non-linearity.
In that way, the current passes through a single stage “folded cascode”, that is converted back to the voltage through another resistor. The resistors act stable, but over the time current may change slightly. This translates into the slow change of the gain (5 ÷ 10%) over the interval of few hours. After, that it fully stabilizes. Audio Analogue had concluded, that the change in volume related to the recording levels of the music is much more significant…
Reducing the power supply disturbs
Reducing of the power supply disturbs represents an important quality of the amplifiers with feedback. Any disturbance source that is not present on the input is more or less attenuated. In order to achieve the same result without feedback greatly design ed power supply is needed and the primary layout should not be affected by the magnetic flux dispersed by the transformer (calling for the need of well designed toroidal transformer).
Even when distortion is decreased to the levels, that is almost not measurable, the question has arisen if it matters quality wise, as the feedback brings good results if the amplifier is properly designed.
And they’ve asked themselves… What is really necessary?
After a lot of digging into the theory, trial & error, and prolonged listenings, they’ve concluded, that when it comes to the pure tones with low order harmonics people are generally able to perceive only values above a few percents and with some higher order harmonics it becomes difficult to hear up to 0.5%…
With 50W at 8Ω, the Puccini Anniversary hold around 0.3% and 0.8%, going back to 20KHz. Was it enough? Well, Audio Analogue let anyone decide for themselves, but as you’ll read on, they’ve accomplished something very right…
Stabilisation of the operating point
Audio Analogue belies, that stabilization of the operating point is the most important and absolutely necessary thing.
For this very reason, they’ve have included a DC Servo (then a feedback!!!) that operates between the DC current and 0,02Hz. The servo output practically stops at 20Hz and then all the feedback acts beyond of the audio band. Many amplifiers make use of DC servo and Audio Analogue strongly believes, how its presence is not noticeable.
The other questions that Audio Analogue asked themselves was if the adoption of feedback is an absolute evil?
“Absolutely not, the feedback is good, sometimes indeed great, but, in the case of the audio, you can live without it. Obviously, we are talking about global feedback. The local feedback cannot be eliminated. It can definitely be minimised, but it is there and frankly, in our view, also does very well.
In the end, does having no feedback has some advantage? In our opinion, the amplifier without feedback is less sensitive to the type of load to drive. Indeed, apart from the lower damping coefficient, it has much quieter behavior on reactive loads. Has no tendency to oscillate, does resonance peaks at high frequency (in fact in Puccini Anniversary there is no Zobel network) does not saturate the input stages and never has the two inputs of the differential free to be used in a balanced configuration without having to pass the signal through the operational.”
And the final question is, of course, does this brings a better sound? Audio Analogue is a strong advocate of such approach and this is why they’ve chosen a more difficult path of designing an amplifier in the absence of typical feedback.
OPERATIONAL
Puccini Anniversary chassis is made out of thick metal with the massive 14mm solid aluminum front panel, that host all the main controls. The recessed central knob has double functions for switching the integrated on and off, as well as for changing the inputs.
Everything on the front panel was designed to offer ergonomic and straightforward-hands on a simple operation and the same goes for the included remote control, that offers all the main functions.
When turned, the central knob activates an encoder that instantly communicates with four digital high precision Analog Devices potentiometers (two per channel). Puccini Anniversary has a unique feature, that allows choosing from four curves, that are calculated to work best with the given sensitivity of the speakers.
Stylish white illuminated LEDs shows all the needed information and the brightness can be adjusted in two level of intensity or switched off.
On the backside, there is plenty of the inputs. All of the RCA connectors are gold-plated, high-quality, Teflon insulated, soldered directly to the input’s board and activated via signal relays.
Audio Analogue Puccini Anniversary is fully functional dual-mono design. At the very heart of the amplifier, the power supply implements 700VA transformer and in combination with the six pairs of ON-Semiconductor transistors (three per channel) delivers 80W at 8Ohm impedance, which translates to around 300W at 2Ohms impedance. This ensures Puccini Anniversary enough power to drive potently even more demanding speakers.
But, there is even more on the inside, that makes Audio Analogue integrated interesting. All power amplifier stages are set on the separate boards. All the Printed Circuit Boards uses golden copper footprints, that are double the thickness compared to the standard PCBs. This ensures much better electrical conductivity.
All the internal wiring consists of pure solid 7N OCC copper conductors. The carefully selected material like military grade resistors, audio-grade polypropylene capacitors, gold plated copper binding posts and a number of other solutions bring a refined performer, that was properly voiced and fine-tuned by the founder of Airtech – Claudio Bertini after numerous evaluations and prolonged listening sessions.
SUM UP
I’ve experienced a pleasant déjà vu with Audio Analogue Puccini Anniversary integrated amplifier. I can still remember the original version, that had even back in time accomplished something very different.
Most importantly, Puccini Anniversary is not just another integrated amplifier. I’m always enlivened and inspired when the manufacturer takes time to fine-tune and voice the high-end audio electronic to operate intimately within the music’s DNA and language.
Audio Analogue mighty, musical heart allows to quickly connect and reconnect with the familiar and beloved music material, without typical curtains of sonic ballast.
In the era where integrated amplifiers are again finding their meaningful space within the homes of audiophiles and music lovers, Audio Analogue Puccini Anniversary integrated amplifier not only represent a great value but delivers music with enough drive and emotional involvement, that allows an instant hook up with the beloved sonic mediums.
Stay tuned for part two, where I’ll sum up my thoughts and include some of the music references.
Matej Isak
PRICE
€3990.00 (official Italian – European retail including 22% VAT)
TECHNICAL SPECIFICATIONS
Sensitivity (70W @ 8 Ω) = 370mVRMS
Max Power (1kHz):
8 Ω = 83.65 Watt 4 Ω = 159.01 Watt 2 Ω = 288.24 Watt
8/4 Ratio = 1.90
4/2 Ratio = 1.81
Slew Rate = 20V/μs
S/N = -100dB (20 Hz – 20 kHz)
-104dB (weighted “A”) THD vs. Amplitude = see figures
Weight: 18kg
Dimensions width 445mm, height 120mm, dept 390mm
CONTACT
AF GROUP SRL
Viale Cesare Battisti 126/G
51015 Monsummano Terme(PT)
Italy
Tel: +39 0572 030964)
Email: info@audioanalogue.com