ALLNIC AUDIO HA-5000 Manuale d'uso - Pagina 4
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INTRODUCING THE HA-5000 HEAD AMPLIFIER
The HA-5000 is Allnic Audio's pre-preamplifier, or "Head
Amplifier". It is an active, tube based device for
amplification of low voltage signals from moving coil
cartridges to allow connection of moving coil cartridges
to the moving magnet inputs of a phonostage, such as
the Allnic H-7000 or H-1500. The HA-5000 is an active
pre-preamplifier, not a "step-up transformer" like
Allnic's AUT-2000, which uses only a transformer to
boost the signal from the cartridge.
The HA-5000 has the following features.
•
Innovative Fixed Bias Circuit
In the HA-5000, two nuvistor 7895(6CW4) tubes, the
smallest vacuum tube, perform as amplifying devices. They
magnify the tiniest signal in audio, the output voltage of MC
cartridges, to match to the MM input of phono
stages. Allnic applies its innovative, fixed bias circuit to
achieve quiet and stable operation of the extremely
sensitive 7895 tubes. The fixed bias circuit eliminates the
subsonics so harmful to phono stages and inherent in the
characteristics of the R.I.A.A curve, which requires
amplification of the lower frequencies. The fixed bias circuit
applies a sustained negative DC voltage to the grid of the
tubes and to the input coupling capacitors, blocking
capacitor "crossover distortion". This distortion is a
common phenomenon but, unfortunately, is often
neglected in pre-preamplifiers. The result of no "zero
crossover distortion" is, simply, clearer and more vivid
reproduction of the music.
•
Very High S/N Ratio
The above mentioned characteristics of the R.I.A.A curve
demand a hum-free pre-preamplifier and, therefore, a silent
power supply circuit. Even one micro volt (1/1,000,000 of
one volt) of hum noise (120Hz hum) in the output signal of
a pre-preamplifier will result 63mV to the loud speakers.
That is unacceptable, and Allnic has overcome the issue
through its automatic pure vacuum tube voltage regulation
circuitry. This voltage regulation circuit minimizes power
supply hum noise to inaudibility.
•
Extreme Wide Frequency Range
Though the HA-5000 has a single gain stage and no
negative feedback, its frequency range capability
extends from 15Hz to 125Khz(-3dB), revealing the full
richness of the musical information on vinyl.
•
World unique 2 MC inputs
Without any hum or switching "popping" noise. You can
play two MC cartridges with convenience.
•
Ultra Flexibility
The capability to follow an unpredictable musical
signal with ease is strongly believed to be the heart
of musicality for audio equipment. This ability can
be indicated by square wave response at high
frequencies, especially at 10Kh and the even more
rarely
achieved
20Khz.
expectations, Allnic's HA-5000 shows a response
shape that is, even at 100Khz, in a word, beautiful.
•
Micro-Phonic Free Tube Damping Know-how
Allnic's Absorb-Gel® tube damping know-how
culminates in the HA-5000.
extreme version of this mechanical technology
applied, reducing vibration induced noise in the
sensitive tube amplification circuit to a level never
before realized.
•
Variable Input Load Impedances.
The HA-5000 has four input load impedances: 50,
100, 200, and 800 ohms, selectable from a control
on the front panel. This allows loading according to
the output impedances of your MC cartridges.
Furthermore, these loads are purely resistive, not
the compound one of a step-up transformer,
resulting in a pure and clean sound.
•
As are all Allnic Audio products, the HA-5000 is
fully RoHS (EU Reduction of Hazardous
Substances regulation) compliant in construction
and materials.
Exceeding
these
In the HA-5000, an