Myth Audio myth preamplifier User manual

myth
Myth Preamplifier
User manual
January 2010.
myth Preamplifier user manual
Table of contents:
1.
2.
3.
4.
5.
6.
7.
8.
9.
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Technical characteristics ............................. 3
Connecting the device ................................ 6
Turning on the device ................................ 7
Using jog dial ............................................ 8
Using Touch Screen ................................... 9
Using remote controller .............................. 10
Using Menus ............................................. 12
Special features ........................................ 14
Troubleshooting ........................................ 16
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1. Technical characteristics
Input resistance: 47 kOhm
Output resistance: < 3 Ohm
Signal to noise ratio: 92 dB
Frequency response: 2 Hz - 100 kHz (+0/-0.3 dB)
THD: 0.011% (1 kHz)
Gain: 1 (0dB)
Dimensions (WxHxD): 431 x 95 x 312 mm
Weight: 5 kg
Principle of attenuation: Light Dependent Resistors (LDR) with
automatic channel balancing
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Frequency response
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Total Harmonic Distortion
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2. Connecting the device
Myth Preamplifier is intended for use in close and dry environment.
Surrounding of the device must be clean and dry.
The operating temperature is from 5 C to 50 C. Storage temperature is
from -10 C to 60 C.
The device is using city AC power network 240V/50Hz.
The device is protected with the fuse of 1.16A at the primary of the
mains transformer. In case of necessity, the fuse should be replaced only
with the appropriate type for 1.16A (F 1.16A)
The backside switch puts the device in stand-by state.
The control lamp on the switch indicates that the mains cable contains
a proper grounding. In the case the lamp is off it is recommended to
check the grounding connection of the mains cable before using it.
Device chassis is grounded via mains cable. Analog grounds of RCA
connectors are not grounded.
It is recommended to avoid connecting and disconnecting RCA cables
while the device is turned on. This may cause noise and interference to
the power amplifier, thus making unpleasant noise on the system
speakers. The safest way to connect RCA cables is to completely power off
the device and then to attach desired connectors.
The back panel of the Myth Preamplifier provides five stereo line inputs
and one stereo line output.
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3. Turning on the device
After connecting the device to 240V AC, turn on the switch on the back
side of the case. LED on the mains switch indicates that a proper
grounding is applied to the casing of the unit. If the LED stays off after
the mains cable has been connected, it is probably due to bad grounding
or cable defect. The device is still operational, but keep in mind that the
metal casing is not grounded anymore.
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4. Using Jog Dial
- This feature is obsolete starting from May 2009. Owners of the Myth
Preamplifier with jog dial should contact office@myth.rs for obtaining the
instruction manual for Jog Dial
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5. Using Touch Screen
The surface of the Touch Screen is intended to be used by soft and
gentle tools such as finger, soft plastic pointers or similar. Any use of
sharp and hard pointers such as sharp pencil, finger nail, screwdriver etc.
can cause a permanent damage to the screen.
Operation force needed to cause action on the Touch Screen is from 20g
to 80gr. Response time of the touch panel is less than 30ms.
The Touch Screen surface of the display is divided into six logical
sections:
1. Previous Input
2. Next input
3. Toggle Menu
4. Volume Down
5. Volume Up
6. Mute/Unmute
Touching any of the sections
invokes appropriate function.
5.1. To select input using Touch Screen
Touching the area "Previous Input" the input selection changes in the
following order:
AUX - PC - TUNER - DVD - CD
Touching the area "Next Input" the input selection changes in the
following order:
CD - DVD - TUNER - PC - AUX
Note: The names of the inputs may differ due to customization and user
preferences.
5.2. To set volume using Touch Screen
Touching the area "Volume Down" the volume decreases down to zero
in steps of one.
Touching the area "Volume Up" the volume increases up to 99 in
steps of one.
Note: Depending on the input sensitivity of the power amplifier and of the
speakers, volume levels should be considered relative to the system. For
example, the volume level of 68 may be louder on some more sensitive
speakers, while it may sound quieter on some less sensitive speakers.
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5.3. To invoke Mute and Unmute functions using Touch Screen
Pressing the "Mute" area on the Touch Panel causes the Myth
Preamplifier to completely silent the output signal.
Pressing the "Mute" area on the Touch Panel while the device is muted
invokes the Unmute function, causing the Myth Preamplifier to gradually
increase the volume level up to the level set before Mute was activated.
During the Unmute function no other operation is possible to execute.
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6. Using the remote controller
Myth Preamplifier is equipped with a remote controller unit.
The remote controller unit uses 4xAAA batteries the life of which is
expected to be 2 years under normal usage of the controller. The LED in
the top left corner is used as indicator of battery health and as soon as it
fades during operation, the battery set should be replaced.
It is recommended to use only alkaline batteries.
It is recommended to replace old batteries only with a new battery set.
The remote controller uses standard Philips RC5 infrared coding for
sending commands to the Myth Preamplifier. In case the remote controller
unit is damaged or lost it can be replaced with any compatible Philips RC5
remote controller unit, or users can contact the Myth office for getting the
original remote set.
The remote controller unit consists of 6 buttons with the following
functions:
1.
2.
3.
4.
5.
6.
Previous Input
Next input
Volume Down
Volume Up
Mute/Unmute
Stand by
Pressing any of the buttons will cause appropriate action.
6.1. To power up the device using Remote controller
Pressing the "Power" button on the remote controller will cause the
device to power up. After the device is initialized and has reached a
steady state it is possible to turn it off by pressing the "Power" button
again.
Once in stand by state it is necessary to wait for at least three seconds
while the unit responds again to a command from the Remote Controller.
This delay is introduced for safety reasons and to prevent fuse from
burning due to peaks caused by fast switching of the mains power supply.
6.2. To select input using the Remote controller
- Using buttons "Previous Input" and "Next Input" on the remote
controller it is possible to change desired audio input.
If the "Previous Input" button is pressed the input selection changes in
the following order:
AUX - PC - TUNER - DVD - CD
If the "Next input" button is pressed the input selection changes in the
following order:
CD - DVD - TUNER - PC - AUX
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6.3. To set volume level using the Remote controller
- Using buttons "Volume Down" and "Volume Up" on the remote
controller it is possible to change volume level of the output.
If the "Volume Down" button is pressed the volume decreases down to
zero in steps of one.
If the "Volume Up" is pressed the volume increases up to 99 in steps
of one.
6.4. To invoke Mute and Unmute functions using Remote Controller
Pressing the "Mute" button on the remote controller causes the Myth
Preamplifier to completely silent the output signal.
Pressing the "Mute" button again while the device is muted invokes the
Unmute function, causing the Myth Preamplifier to gradually increase the
volume level up to the level set before Mute was activated. During the
Unmute function no other operation is possible to execute.
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7. Using Menus
Myth Preamplifier provides optional settings which can be accessed and
set by users. The options are organized in three menus available and can
be accessed via Touch Panel:
1. Main Menu is used for setting desired input and volume level. This is
the default menu,
2. Display Menu is used for setting backlight power off and backlight
intensity of the display,
3. Setup Menu is used for setting the number of volume controls and
auto power off.
7.1. Using the Main Menu
The Main Menu contains functions for setting input, volume level, mute,
menu select and powering on/off device.
7.2. Using Display Menu
While in the Main Menu a gentle touch on the "Select menu" area
causes the Display Menu to appear. The first option in the Display Menu
gives the possibility to choose the period during which the backlight will
stay on before it completely
turns off. The available options
are 0 to 10 seconds. If the
period is set to zero then the
backlight of the display will
always stay turned on during
the preamplifier operation.
The lower part of the screen
provides the option to choose
the intensity of the backlight.
The available options are 0 to
10, zero meaning the backlight
is completely turned off.
7.3. Using the Setup Menu
While in the Display Menu a gentle touch on the "Select menu" area
cause the Setup Menu to appear.
The first option in the Setup Menu "Volume Levels" gives the possibility
to choose number of input volume controls. The available options are 1
and 5.
If set to 1 then all line inputs have the same volume control.
If set to 5 then each line input have its own volume control. This option
is useful if sound sources attached to preamplifier inputs have different
output levels, thus causing large swings in volume levels if the inputs are
switched back and forth. All the same, this option is useful for "A/B" tests
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of audio equipment. For example, if source A provides larger output level
than source B it is necessary to adjust volume level each time the input
selector switches from A to B and vice versa. However, setting the Myth
Preamplifier to 5 volume levels makes it possible to separately adjust
volume levels for A and B sources, thus making it more pleasant if
frequent input switching between A and B source is done.
The second option in the Setup Menu is "Auto Power Off". This option
makes it possible to automatically turn off the device after specified period
of inactivity. The available options are 0, 30, 60, 90 and 120 minutes.
Please note that the Myth Preamplifier does not feature a precise clock
circuitry. Therefore, the suggested periods are not to be used for
measuring time, they are provided as an orientational information.
The Auto Power Off option is very useful in conjunction with the Trigger
Output of the preamplifier. When the Myth Preamplifier is turned on the
Trigger Output provides the signal to power amplifier to be turned on too.
All the same, if the Myth Preamplifier is turned off then the signal on the
Trigger Output is not present which makes it possible to automatically
turn off the power amplifier.
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8. Special features
8.1. Trigger Output
Some power amplifiers, such as the Myth Power Amplifier, provide a
"trigger" input for being turned on or off externally. Connecting the Myth
Preamplifier trigger output to trigger input of a power amplifier makes it
possible to control the operation of the power amplifier as well.
Once turned on, the Myth Preamplifier provides a DC voltage on the
Trigger Output. The voltage level is 15V and it is not stabilized, neither it
is protected with fuse. Note: Before connecting the trigger output to a
power amplifier read the specification of the power amplifier and make
sure that it can accept the 15 V DC to its trigger input. Also, avoid short
circuiting the trigger output as it may stop to function properly.
8.2. Auto Balance
The Myth Preamplifier contains a microprocessor unit which controls the
operation of the Light Dependent Resistors (LDR). Due to different
behavior of each LDR element, it is very important to adjust operation of
each LDR in order to equalize volume levels of left and right output
channels. Microprocessor unit in the Myth Lighspeed Preamplifier uses a
smart algorithm for perfect matching the output levels of left and right
output channel. The equalization is successfully done on each volume level
available in the Myth Preamplifier, therefore there is no level difference in
channels when listening quiet or loud music.
8.3. Internal Power Supply
The Myth Preamplifier contains two separate power supply units, for
digital and analog section. Both units are galvanically separated and have
no physical contact which eliminates the interference between the two and
takes it to the absolute minimum.
The analog power supply section is made with special care and it uses
high quality filter capacitors and qualitative voltage stabilizers for the best
performance. Moreover, the output stage of the preamplifier is equipped
with current source buffers the operation of which does not depend on
voltage swings in power supply, thus giving even more dynamics and
musicality to the sound.
8.4. Internal wiring
Internal wiring of the analog section is taken to the minimum. All audio
signals travel at very short paths from input to output. The analog signal
paths of the Myth Preamplifier are actually only the PCB tracks. RCA
connectors are soldered directly to the PCB and no other wiring is used for
this purpose.
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It also is worth mentioning that the Myth contains no capacitors in the
signal path.
8.5. Sound characteristics
The Myth Preamplifier is designed to sound as transparent as possible.
The idea behind this design is that the rest of the equipment in user
system gets to be easier to find match among components. Having a
transparent sounding preamplifier gives more options in choosing other
components of the system. Moreover, the Myth Preamplifier perfectly
matches with both tube and transistor power amplifiers. Its neutral sound
in no way influences the choice of the power amplifier and sound sources
in general.
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9. Troubleshooting
9.1. The device does not power on
Make sure that the device is attached to mains 240V/50Hz.
Make sure that the fuse is in healthy condition and replace it with a
new one if necessary.
9.2. The device does not respond to remote controller
Make sure that the signal LED on the remote controller is lit when a
button is pressed.
Check the batteries and if necessary replace them with new ones
Check if the IR sensor on the preamplifier is not covered or hidden.
9.3. The sound is distorted and/or quiet
Check if the RCA cables are properly attached. Replace cables with well
tested ones to make sure that there is no cable malfunction.
Make sure that the sound source is operating properly.
In rare cases some non standard sound sources, such as rare DIY
equipment, provide very low output levels, even below 1V. Since the Myth
Preamplifier has the maximum gain of 0dB, the input signal of the
preamplifier provided to the power is amplifier also below 1V. This may,
however, not be enough for some power amplifiers to operate properly.
Check the documentation of your power amplifier provider to see what are
the minimum input levels required for proper operation and check what
are the output levels of your sound source.
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NOTES:
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