© by www.audioalto.com
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AUTHOR AND FOUNDER FOREWORD
Dear customer,
Let me express my thankfulness for granted trust in buying Audio Alto’s
product.
AA DMI 3 H is part of Audio Alto family products. All my products follow our
philosophy. At Audio Alto we strive not only to achieve perfect reproduction
of sound that preserves all the purity, openness, width and depth of the
original but we also aim for aesthetic perfection and this “Compact series”
product confirms it.
Our entire electronic product family follows the same concepts: all voltage
amplifying circuits are class A topology and some of them are also single
ended. I also believe that vacuum tubes as voltage amplifying components
deliver the most natural and detailed sound reproduction. The vacuum tube
is also capable of amplifying the analog audio signal without using global
negative feedback and maintaining the required linearity. To achieve the
same linearity with solid state topology many more components must be
involved, meaning that the audio signal must pass through them. With triode amplification only one capacitor and
three resistances are involved so the signal is much closer to the amplified original. I believe that the use of global
negative feedback (GNFB), especially in the power amplifier that drives the speaker, lowers the openness,
naturalness and micro details that most of the music is made from.
Most producers and technical reviewers, while testing power amplifiers, use artificial passive load (made of
resistances, impedances and capacitances) but the speakers that the amplifiers are driving are somehow “live” loads.
The speaker (the build in driver) generates induced voltage as a result of the cone movement in the magnetic field.
Part of this voltage, which holds (mostly unpleasant) information of the speaker box and ambient reflections, is
projected through GNFB to the input of the power amplifier. In reality this induced voltage should (must) be ignored
and shouldn’t be (re)amplified again and transferred back to the speaker, generating new induced voltage that
returns back to the amplifier input and so on…
Using GNFB lowers development and production costs and is somehow a must in large(r) scale production. As my
products are produced in small quantities and mostly upon customer orders (requests) Audio Alto can follow the
more difficult path in developing producing audio products that sound "correct" (compared to the more widespread
commercial products).
To fulfill this concept all parts of the amplifying circuits must be chosen and tested before installed as there is no
active GNFB correction of the parts and their linearity problems. As Audio Alto products DO NOT USE GNFB, the
amplifiers output impedance is usually higher (the damping factor (DF) is lower). I do believe that this approach gives
the speakers the ability to perform and deliver to the listener openness, naturalness and micro details as the listener
is expecting. Audio Alto speakers are designed so that their box Q factor (box damping) is correct per se without
requiring the driving capabilities of the attached amplifier (“usually” it’s a high damping factor).
AA DMI 3 H includes all the previously mentioned concepts. Its DF is 15 for optimal (well designed) speaker driving,
but the user can also select a DF = 50 for less damped speakers. It also includes a new practical way of correcting
speaker response (called TILT – as was introduced in the year 1982 - in a Quad preamplifier).
I’m confident that the reproduction it will give you is very natural and pleasant and that it will give you many years of
listening pleasure.
Yours sincerely,
Sasha Burian
