Audiopax 5 User manual

MODEL 5

1
Index
Introduction 2
Installation 3
Back Panel 5
Turning on your Model 5 6
The Timbre Lock®7
Specifications 9

2
Introduction
Thank you for purchasing an Audiopax Model 5, the fourth generation of our
award-winning preamp that is the result of combining a unique topology with the best
audio components available - absolutely unique equipment.
Audiopax preamps redefine the role of these components in an audio system,
directly and controllably embodying the concept of “synergy” among their components.
They are the only preamps in the world to incorporate the Timbre Lock®technology,
which allows the adjustment of minimal distortion perceived in the system as a whole
and during the listening of it, breaking away from the conventional concept of single
component measurements. Because of this, its inclusion in systems is often described
as “magical”, revealing all the nuances, dynamics, intentions and emotions of music
and musicians, something usually only present in live performances.
Other features and innovations also contribute to the maximum performance of
the systems in which they are inserted: the absolute lack of feedback, a unique Mosfet
topology where this solid-state element is effectively used as a tube (that's why many
consider the inclusion of an Audiopax preamplifier as “the tube” element in their
systems) and an innovative use of inductive loads (as opposed to conventional
resistive loads), where the perceived final dynamics are raised to levels hardly ever
achievable by any other market preamplifier. It is no wonder that Model 5 has
amassed an impressive number of excellent reviews, awards and “Best of the Show” at
the world's leading audio shows.
Extensive frequency response, exceptional low-level resolution, visceral
dynamics and tremendous immunity to load shifts. Refinement and innovation bring
your new preamp to the reference category.

3
Installation
Your Model 5 is shipped in a single box containing:
●The preamp unit
●The external power supply
●Two dc cables
●A remote control
●A small antenna for remote control reception
●Reserve fuses
Your manual is available for download on our website: www.audiopax.com.
Model 5 should be installed in a location with natural ventilation and at least 10
cm (4 inches) of free space above its handles (use in enclosed cabinets could
endanger its components and void your warranty). Both the preamplifier and its power
supply must be installed away from equipment that may generate electromagnetic
interference (such as power conditioners) and the power unit must be at least 50 cm
away from the main chassis.
Recommendations for its installation and use:
●Install it with all system equipment turned off. Also, make sure that the
power on/off and standby switches of the power supply and preamplifier
are turned off.
●Connect the source and the preamplifier with the two supplied dc cables.
The colors of the cable connectors match the colors of the cabinet
connectors and there is no possibility of reversing these cables, which
are only pluggable in the correct position.
●At the power supply module: Install the supplied antenna into the
corresponding input and set the grounded/ungrounded switch to the
grounded position.
●On the preamplifier module: Select both rear switches to the upper
position ("unbalanced" and "High Gain").
●Make all necessary audio input and output connections.
●Connect the AC power cord using the proper voltage - Model 5 can be
supplied for 120V or 230V, but you cannot change this selection on your
own (contact Audiopax if necessary).
●We recommend that the power supply be continuously turned on and all
on/off operation be performed by the preamplifier front panel "standby

4
on/off" switch, except when it is recommended that the entire system be
turned off (such as during trips).
●After power-up, Model 5 will need 30 minutes to reach its thermal
stabilization, which will guarantee its best performance.
Some important notes:
●Bypass input does not go through volume control (it will always have
maximum gain) and it is available to allow easy integration of Model 5
into a multichannel system without the need for cabling changes. If it's not
used in this mode, we recommend the use of short circuit RCA caps in
these inputs, avoiding unwanted noise in the case of standby off or power
off. It will be switched to output in three situations:
○Manually by the channel selection front switch.
○Automatically when the pre is turned off, either by the front panel
"standby" switch, the power supply "on/off" switch or due power
failure shutdown (eg unplugged from the ac cable).
○The cd player input can also be used with 3-pin (XLR) connectors
by simply switching the "unbalanced/balanced" switch on the back
panel of the preamplifier to the "balanced" position.
○The three outputs (two RCA and one XLR) operate simultaneously
and any of them can be used.
○3-pin input and output (XLR) can be "pseudo-balanced" (only an
XLR cable adapter, but operating as unbalanced) or transformer
balanced, the latter being a Model 5 option.
●Both inputs and outputs follow the white/red and upper/lower conventions
for left/right channels.

5
Back Panel
From left to right:
bypass switchable input manually (via channel selection front switch) or
automatically (in case of power failure, standby off or power off)
auxiliary switchable input via channel selection front switch
cd player switchable input via channel selection front switch
blu-ray player switchable input via channel selection front switch
media center switchable input via channel selection front switch
rec out channel selection output but with no change through volume
control (always at maximum).
out1 / out 2 preamp outputs
xlr - right out/in output (top connector) and input (bottom connector) 3-pin (XLR) -
right channel
xlr - left out/in output (top connector) and input (bottom connector) 3-pin (XLR) -
left channel
gain preamplifier gain selection switch: 18dB (high) and 9dB (low).
ATTENTION: to avoid noise in your loudspeakers please only
change this setting with the amplifier turned off or with
bypass input selection (manually or automatically)
cd in unbalanced and balanced selection for cd player input
power a/b connectors for power supply

6
Turning on your Model 5
When Model 5 power is turned on by using the power on/off switch of the power
supply, the front LED of the power supply should light but not the front LED on the
preamplifier, as it remains for 40 seconds in its previous state (switched to bypass
input). After this period (and with the front panel switch on standby on) the preamplifier
led will also light up and the input will be switched according to the front panel
selection.
As initial setup we recommend the following positions:
●Put the Power Supply Unit rear switch to its "grounded" position. The
ungrounded position should only be used to test for potential system
grounding problems that may cause noise (such as "ground loops"), that
is, even if its use apparently resolves some kind of problem, it is
important that the original electrical problem be corrected to allow you to
return this switch to its normal (grounded) position.
●Put the "Gain" switch on the back of the preamplifier to high.
●Put "cd in" switch on the back of the preamplifier for unbalanced for the
use of RCA input cables or balanced for the use of XLR input cables.
●Put Timbre Lock®potentiometers and volume at minimum (zero)
position.
●Be sure that the "Standby on/off" switch at the preamp is in its off position
before connecting the power supply.
It is also always recommended that the preamplifier be turned on before the
power amplifiers.

7
The Timbre Lock®
Every audiophile has heard and used the term "synergy", which represents the
perfect match between the parts of a system. It is a continuous pursuit of the high-end
audio market, justifying numerous tests and equipment changes. This demand is
usually based on trial and error processes and often gives any audiophile not only the
expenses associated with continuous exchanges but also frustrations rather than only
good results.
Timbre Lock®, a unique innovation of Audiopax, can be considered a control
that acts on exactly one of the most important parameters that define our impression of
"synergy" among the components of a system: the joint behavior of its distortions. They
are present in all Audiopax preamps and amplifiers and replace the "trial and error"
process of continuously changing equipment and parts of a system with a set of simple
potentiometer adjustments. Model 5 preamp follows the same Timbre Lock®concept
originally developed for Model 88but with a different implementation.
Sound effects do not operate in the domain of frequency response, as in today's
little-used tone controls, but rather operate in optimizing the residual harmonic
distortion spectrum amid the preamplifier, amplifiers, and speakers. Because of this, its
final effect is difficult to define and inherently dependent on the system itself.
Improvements in instrumental tone perception, micro-dynamics, general definition, low-
frequency impact and articulation, and even more subjective factors such as emotional
involvement and the real sense of the presence of musicians in your listening room are
often observed.
It is impossible to predict the optimal configuration for each case, as the result
will be dependent on the systems and the listening rooms themselves. Adjustments
should, therefore, be made through comparative hearings by the users themselves.
Remember that since the Timbre Lock®also acts on the final gain of the preamplifier it
is very important to balance the volume levels during the tests with the volume control.
The adjustments are very dependent on the characteristics of the speakers and
also on the amplifiers used but we can have the following list as an initial reference:
●Class A tube amplifiers (like all Audiopax amplifiers) tend to perform best
with the Timbre Lock®set to low (between zero and -10).

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●High power solid-state amplifiers tend to operate best with the rear switch
in the “low” position and the Timbre Lock®at high values (between -30 and -40).
●High-power push-pull tube amplifiers usually have their best settings
between the two extremes (between -10 and -30).
One last important note: Model 5 is an inverter preamplifier, ie the output signal
will have inverted polarity relative to the input. When coupled to an inverter amplifier
(as is the case with all Audiopax amplifiers) the preamplifier/amplifier combination will
preserve the polarity of the input signal. If non-inverting amplifiers are used, absolute
polarity restoration can be achieved by reversing it at the source (if available) or simply
reversing the polarity of the loudspeaker cables in both channels (left/right). We
encourage system testing with both configurations, as the best optimization of the
residual distortion spectrum may occur in either case.

9
Specifications
Frequency Response: 5Hz to 90kHz (-3dB)
Maximum gain: 9dB (low) / 18dB (high)
Signal to Noise Ratio: Better than 95db, Weighted Ref, 1V
Input Impedance: 45 Kohms (minimum)
Output Impedance: 1500 ohms (maximum)
500 ohms (typical)
Distortion: <0.08%
Input Voltage: 120V or 230V (+- 5%)
Fuses: 1A (120V) or 500mA (220V), slow, 6.3mm (main)
250mA to 500mA, fast, 6.3mm (dc - two units)
Dimensions: 42cm (W) x 34cm (D) x 14cm (H) (Preamplifier)
30cm (W) x 29cm (D) x 9.5cm (H) (Power Supply)
Net Weight: 12 Kg (Preamplifier)
5 kg (power supply)
Finishes: Chassis: Chrome or Black Piano
Sides: Black Piano or Bordeaux
Optional: Transformer balanced input and output
Dual balanced input
All of the above specifications consider the Timbre Lock®controls at minimum and
Volume at maximum.