M2TECH
MARLEY
DUAL-DRIVE CLASS-A HEADPHONE AMPLIFIER / Preamp
USER MANUAL
REV. 1.0 – 11/2013
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REVISION 1.0 – NOVEMBER 2013
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Warning!
Changes or modifications not authorized by the manufacturer can invalidate
the compliance to CE regulations and cause the unit to be no more suitable to
use. The manufacturer refuses every responsibility regarding damages to
people or things due to the use of a unit which has been subject to
unauthorized modifications or to misuse or to malfunction of a unit which has
been subject to unauthorized modifications.
This unit is compliant with the following CE regulations: CEI EN 55022:2009 Class B (Radiated
Emissions), CEI EN 55024:1999, CEI EN 55024:A2/2003, CEI EN 55024:IS1/2008 (Radio Frequency
Electromagnetic Fields, 50Hz Magnetic Field Immunity Test and Electrostatic Discharges – ESD).
For a proper operation of this unit, all connections to other equipment in the system must be
done when all equipment are off. Failing to comply with this advice may lead to damage to the
Marley.
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The label above, printed on the product case, indicates that the product, when no more usable, can’t
be treated as generic garbage, but must be disposed of at a collection point for recycling of electrical
and electronic equipment, in compliance with the WEEE regulation (Waste of Electrical and Electronic
Equipment).
By making sure that this unit is correctly recycled, you will help preventing potential damages to
environment and human health, which could be caused by a wrong treatment of this product as
generic garbage. Materials’ recycling helps saving natural resources. For more in-depth information
about recycling this product, please contact M2Tech Srl.
WARNING: the information contained in this manual are considered to be reliable and accurate.
M2Tech reserves the right to change or modify the information any time, without prior advice.
It’s up to the customer to ensure that the manual being consulted is the latest version.
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Dear customer,
Thank you for purchasing MARLEY. What you have is a first rate dual headphone
amplifier with preamp and line outputs. MARLEY also includes many unique features
conceived to obtain the best audio performance out of any headphone or source.
MARLEY implements a specific set of functional and technological solutions, from the
double output stage to high bias, with the purpose of exalting superior sonic
performance, ease of use and reliability.
MARLEY is provided with a complete set of outputs which allow for using any kind of
headphones, be they fit for single-ended drive or for balanced drive. The high
maximum output level delivered by the MARLEY allows for effectively driving even the
most difficult headphones. For your convenience, we allow for two sets of
headphones to be operated independently of each other at the same time using
single-ended drive.
We’re sure that your expectations will be met by purchasing the MARLEY: you’ll hear
your favorite music like never before. Be ready for a new listening experience!
Nadia Marino, CEO
Please annotate your MARLEY serial number and purchase date for future reference:
S/N: ____________________________________
Date of Purchase: __________________________
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INDEX
1. Unpacking and Placing the Unit.............................................................................. 9
2. Front Panel ........................................................................................................... 11
3. Back Panel............................................................................................................ 13
4. Connecting and Powering the Unit ....................................................................... 15
5. Cleaning the Unit .................................................................................................. 17
6. Using the Marley ................................................................................................... 18
6.1. Volume Setting ............................................................................................... 19
6.2. Muting Toggle................................................................................................. 20
6.3. Source Selection ............................................................................................ 20
6.4. Balance Setting .............................................................................................. 21
6.5. Output Mode Selection................................................................................... 22
6.6. Volume Display Mode Selection..................................................................... 23
6.7. Auto Switch-Off Setting .................................................................................. 24
6.8. Display Dimming ............................................................................................ 26
6.9. Firmware Revision.......................................................................................... 27
6.10. Switch-Off..................................................................................................... 28
6.11. Notes About Menu Use ................................................................................ 28
7. Balanced Drive and Single-ended Drive ............................................................... 29
8. Technical Specifications ....................................................................................... 31
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1. Unpacking and Placing the Unit
Lay the box on a table and open it by separating it from the external paperwork and
removing or cutting the adhesive tape seal. The following items are included:
•
•
•
One MARLEY;
One wall wart;
This manual.
Should one or more item be missing, please contact your dealer.
Remove the MARLEY from the foam enclosure and place it onto a stable base, far from
heat sources. Avoid full sunlight on the unit. Allow for ample room around the unit for
venting.
The MARLEY is a high bias dual drive class A amplifier which dissipates 30W while
operating, even when idle; therefore a lot of heat is produced. As a result, it is
necessary to guarantee adequate air flow.
Avoid smoke, moisture, dirt and water reaching the unit.
Do not place the unit on thick carpets or inside a box or piece of furniture, not even
close to curtains.
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2. Front Panel
Figure 1
1) On/off/mute/menu escape button. Push this button to turn the MARLEY on when
it’s off. When the MARLEY is on, a short push will toggle muting, unless the menu has
been previously accessed: in the latter, a short push will cause immediate menu
escape and configuration changes discard. A prolonged button push while the MARLEY
is on will cause it to switch-off.
2) Display. Multi-function LCD display. During normal operation, it indicates the
listening level for the active outputs, the selected source and the mute status. When
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the menu is accessed, the display shows the selected menu item and the current
value associated to it.
3) Encoder. Allows for accessing and navigating the menu, as well as volume
setting. It may be rotated and pushed. Please read chapter 6 for details on its use.
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3. Back Panel
Figure 2
4) Inputs. Connect stereo music sources to these two inputs. Gold-flashed RCA
sockets. Black indicates left channel, red indicates right channel.
5) Tape output. Connect the input of a tape recorder or other recording device to this
output to record the selected source. Gold-flashed RCA sockets. Black indicates left
channel, red indicates right channel.
6) Preamplifier output. If used, connect a power amplifier to this output, to use the
MARLEY as a preamplifier. Gold-flashed RCA sockets. Black indicates left channel, red
indicates right channel.
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7) Output for single-ended headphone connections. Connect the jack of a
headphone set to each of these two outputs. It is possible to use one output or both
outputs at the same time. These two connectors should be used as alternative to the
balanced headphones connector (item 8). 6,35mm (1/4”) stereo socket.
8) Output for balanced headphones connection. Connect the XLR connector of a
headphone set to this output. This connector should be used as alternative to the
single-ended headphones connectors (item 7). 4-pin female XLR socket.
9) Input for high-current, low-noise power supply. Connect the plug from the
dedicated high-current, low-noise power supply dedicated for the MARLEY. 4-pin, male
XLR socket (optional purchase).
10) Input for power from wall wart. Connect the jack from the supplied 15V-2A wall
wart included in the package. 5.5/2.1mm jack with positive on tip.
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4. Connecting and Powering the Unit
WARNING: All connections between the MARLEY and other equipment must be
made when all units are off. Failing to do so may cause damage to the MARLEY
and/or other units.
Please refer to chapter 3, “Back Panel”.
Connect one or two high-level stereo audio sources (CD/SACD/DVD player, DAC
USB, tuner, preamplifier) to the inputs (Figure 2, 4). Low-level sources, such as
magnetic pick-ups, cannot be connected to the inputs.
If needed, connect MARLEY’s “TAPE OUT” output to a recorder’s input (Figure 2, 5).
If MARLEY‘s operation as preamplifier is desired or required, connect the “PRE OUT”
output to the input of a power amplifier (Figure 2, 6).
Connect one or two headphones to headphones outputs, avoiding using singleended and balanced outputs at the same time (Figure 2, 7/8).
Connect the wall wart jack to the MARLEY ‘s power supply input (Figure 2, 10).
Connect the wall wart to a mains outlet. The wall wart is designed to automatically fit
any mains voltage from 90VAC to 265VAC.
Turn the MARLEY on by pushing the front panel button (Figure 1, 1).
NOTE: It is possible to use a dedicated high-current, low-noise power supply in
place of the included wall wart for increased sonic performance. In this case,
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the power supply must be connected to the dedicated connector on MARLEY‘s
MARLEY
back panel (Figure 2, 9). Be sure to make this connection with the MARLEY
disconnected from any power source and with the MARLEY disconnected from
any other device that may have its power source turned on.
WARNING: When the dedicated power supply (optional) is used, DO NOT
connect the wall wart also. The wall wart is NOT needed and NOT used when
you use the external dedicated power supply.
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5. Cleaning the Unit
The MARLEY should be cleaned with a soft, damp cloth. Do not use alcohol nor other
types of cleaning fluids as they could damage the unit.
Avoid fluids from dropping or leaking through the venting grid holes. Fluids of any
type poured into the venting holes will void your warranty.
Be careful not to scratch the Plexiglas front screen.
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6. Using the Marley
At power up, the MARLEY observes a start-up heating period lasting a few seconds,
during which the flashing writing in Figure 3 is displayed.
HEATING UP
POWER AMPLIFIERS
Figure 3
Once heating is completed, some general information about MARLEY operation will
appear on the display, as shown in Figure 4 and Figure 5. The two pictures refer to
the two different output configurations (balanced and double single-ended). In Figure
4 the word “MUTE” appears to indicate that muting is switched on.
MUTE
IN:1
VOL:-40DB
Figure 4
>VOLA:-40DB
IN:1 VOLB:-40DB
Figure 5
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6.1. Volume Setting
Volume setting is performed by encoder knob rotation (Figure 1,3). Depending on the
output configuration, it is possible to set one or two volumes.
When the MARLEY is configured in balanced mode, the two stereo amplifiers which are
used in this mode are bridged and make for a single balanced amplifier. This is why
only one balanced output is present and why only one volume control can be set
when using the balanced headphone connection (Figure 4).
When the MARLEY is configured in dual single-ended mode, each amplifier drives one
jack output. Each amplifier has its own dedicated volume control, it is therefore
possible to set the listening level of each amplifier independently. Two volumes are
thus shown: “VOLA”, related to output “A,” and “VOLB”, related to output “B”. The “>”
sign indicates which volume can be set. As shown in Figure 5, output “A” volume can
be set by rotating the encoder knob.
To set volume for output “B” it is necessary to push the encoder knob once, so that
the “>” moves to the front of “VOLB” (Figure 6).
VOLA:-40DB
IN:1 >VOLB:-40DB
Figure 6
NOTE: After setting output “B” volume, the button to the left of the front panel
may be pushed to restore equipment’s “idle” status as in Figure 4. As an
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alternative, after a few seconds past the encoder rotation the unit automatically
reverts to “idle” status.
6.2. Muting Toggle
The MARLEY is provided with a feature (muting) which allow for lowering the volume
20dB without touching the encoder knob. This feature is useful when user needs to
listen to another person for a moment, or while changing music programs in the
source, etc.
Muting is toggled by pushing the button to the left of the front panel (Figure 1, 1).
When muting is engaged, the word “MUTE” appears on the display (Figure 4).
In dual single-ended mode, muting affects both outputs.
WARNING: Carefully operate on volumes when muting is engaged: If volume is
raised too much and muting is disengaged, the resulting listening level could
be so high that damage to the headphone sets or to the listener’s ears may
occur.
6.3. Source Selection
The MARLEY is provided with two inputs, it is therefore possible to connect two
sources to it and select one for listening. To do this, it is necessary to push the
encoder once in balanced mode or twice in dual single-ended mode: the input
selection feature is then accessed as shown in Figure 7.
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INPUT SELECT
INPUT:1
Figure 7
It is possible to select input 1 or input 2 by rotating the encoder knob.
To confirm the chosen input the encoder must be pushed: this way, the input is
selected and the unit reverts to “idle” status.
Note that if the user changes her/his minds and goes for keeping the source
previously selected, she/he only needs to push the button to the left of the front panel
(Figure 1, 1) or avoid doing any other action on the unit, as after a few seconds, the
MARLEY automatically reverts to its “idle” status without changing the source selection.
6.4. Balance Setting
The MARLEY allows for setting the balance (that is, the relative level between left and
right channels) in a range of +/-6dB. To do this, it is necessary to push the encoder
twice in balanced mode or three times in dual single-ended mode: the input selection
feature is then accessed as shown in Figure 8.
CHANNELS BALANCE
L
<>
R
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Figure 8
Left channel level will be increased with respect to right channel’s by rotating the
encoder knob counter clockwise. Right channel level will be increased with respect to
left channels by rotating the encoder knob clockwise.
To confirm the selected balance setting, push the encoder: the balance setting will be
stored and the unit will revert to “idle” status.
Optionally, if the user changes her/his minds and goes for keeping the balance
previously set, she/he only needs to push the button to the left of the front panel
(Figure 1, 1) or avoid doing any other action on the unit, as after a few seconds, the
MARLEY automatically reverts to its “idle” status without changing the balance setting.
6.5. Output Mode Selection
As previously mentioned, the MARLEY may operate in two different output modes,
depending on which type of headphone arrangements the user needs to drive: one or
two single-ended headphones with 6.35mm (1/4”) jack (dual single-ended mode) or
one balanced headphone set with 4-pin XLR connector (balanced mode). To select
the appropriate output mode, it is necessary to push the encoder three times in
balanced mode or four times in dual single-ended mode: As a result, the output mode
selection feature is then accessed as shown in Figure 9.
MODE
DUAL SINGLE-END
Figure 9
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The desired output mode is selected by rotating the encoder knob: “DUAL SINGLEEND” or “BALANCED”.
To confirm the selected output mode, push the encoder knob: the output mode will
be set and the unit will revert to “idle” status.
Optinally, if the user changes her/his minds and goes for keeping the output mode
previously set, she/he only needs to push the button to the left of the front panel
(Figure 1, 1) or avoid doing any other action on the unit. As a result, after a few
seconds, the MARLEY automatically reverts to its “idle” status without changing the
output mode.
6.6. Volume Display Mode Selection
The MARLEY’s volume levels may be displayed in two different fashions: deciBels or in
steps.
In the former, the highest volume is represented by 0dB, while negative figures with
increasing magnitude indicate increasingly lower volume. E.g., -15dB is lower volume
than -20dB.
In the latter, the highest volume is represented by 78, while positive figures with
decreasing magnitude indicate increasingly lower volume. E.g., 40 indicates higher
volume than 30.
To choose the volume display mode, it is necessary to push the encoder knob four
times in balanced mode or five times in dual single-ended mode: The volume mode
display selection feature is then accessed as shown in Figure 10.
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VOLUME DISPLAY
DECIBELS
Figure 10
The desired volume display mode is selected by rotating the encoder knob:
“DECIBELS” or “STEPS”.
To confirm the selected volume display mode, push the encoder: the volume display
mode will be set and the unit will revert to “idle” status.
Optionally, if the user changes her/his minds and goes for keeping the volume
display mode previously set, she/he only needs to push the button to the left of the
front panel (Figure 1, 1) or avoid doing any other action on the unit. As a result, after
a few seconds, the MARLEY automatically reverts to its “idle” status without changing
the volume display mode.
NOTE: The choice of either mode won’t affect the way volume is actually set:
the MARLEY allows for setting volumes between 0 and -78dB with 1dB steps.
Volume display only is changed depending on the choice made as indicated
above.
6.7. Auto Switch-Off Setting
Compliant to UE rules about energy saving, the MARLEY is able to automatically switch
off after a certain time of idle operation. Idle means a time lapse in which the user
doesn’t operate the unit’s controls.
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Auto switch-off time is user selectable (30 to 240 minutes in 30 minutes steps); the
auto switch-off function may be disabled. To do any of the two, it is necessary to
push the encoder five times in balanced mode or six times in dual single-ended
mode: The auto switch-off selection feature is then accessed as shown in Figure 11.
AUTO-OFF
240MIN
Figure 11
The idle time after which the MARLEY switches off is set by rotating the encoder knob.
To confirm the desired auto switch-off time, push the encoder: Time to switch-off is
then stored and the unit will revert to “idle” status.
Optionally, if the user changes her/his minds and goes for keeping the auto switch-off
mode previously set, she/he only needs to push the button to the left of the front
panel (Figure 1, 1) or avoid doing any other action on the unit: After a few seconds,
the MARLEY automatically reverts to its “idle” status without changing the auto switchoff time.
NOTE: To disable auto switch-off, select “DISABLED”, which is one of the
values which appear on the display while rotating the encoder knob, as shown
in Figure 12.
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AUTO-OFF
DISABLED
Figure 12
6.8. Display Dimming
The MARLEY display backlight intensity may be set in four different levels, depending
on user’s preference. Moreover, it’s possible to set an “automatic” mode in which the
display is always of except, for a few seconds, when the unit is operated by the user.
To set display dimming, it is necessary to push the encoder six times in balanced
mode or seven times in dual single-ended mode: Display dimming is then accessed
as shown in Figure 13.
BACKLIGHT
0
Figure 13
Intensity is chosen by rotating the encoder knob: Level “0” is for highest intensity,
level 3 is for lowest intensity. “Automatic” mode is selected when choosing “AUTO”.
To confirm the desired display backlight intensity, push the encoder: Intensity is set
and the unit will revert to “idle” status.
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Optionally, if the user changes her/his minds and goes for keeping the display
backlight intensity previously set, she/he only needs to push the button to the left of
the front panel (Figure 1, 1) or avoid doing any other action on the unit: after a few
seconds, the MARLEY automatically reverts to its “idle” status without changing the
display backlight intensity.
6.9. Firmware Revision
The MARLEY is operated by a microcontroller. It may be useful to know the revision of
the firmware being executed by the microcontroller. To display the firmware revision,
it is necessary to push the encoder seven times in balanced mode or eight times in
dual single-ended mode: the firmware revision is then displayed as shown in Figure
14.
FIRMWARE RELEASE
1.00
Figure 14
Of course, no value can be changed when accessing this feature: The firmware
release indicator only changes when a firmware update is performed (which can only
be done in the factory).
To exit this feature and revert the MARLEY into “idle” mode, the button on the left of the
front panel may be pushed (Figure 1, 1) or the user should avoid doing any other
action on the unit: After a few seconds, the MARLEY then automatically reverts to its
“idle” status.
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6.10. Switch-Off
The MARLEY may be turned off by a long push on the button on the left of the front
panel (Figure 1, 1). After a few seconds, the advice shown in Figure 15 appears.
POWERING-DOWN
RELEASE BUTTON
Figure 15
Once the button is released, the unit switches off and may be turned on again by a
new short push on the button.
NOTE: In the “Off” status, the MARLEY actually draws a very low current, such as
it may be considered negligible.
6.11. Notes About Menu Use
When the firmware release screen is displayed and the encoder knob is pushed
further, menu navigation restarts from the first item not related to volume control that
is from source selection. If the volume setting mode is desired, it’s then necessary to
exit the menu by either pushing the button on the left of the front panel (Figure 1, 1)
or avoid operating the unit for a while, to allow the MARLEY to automatically revert to
“idle” status.
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7. Balanced Drive and Single-ended Drive
Most headphones are fitted with a 3-pole cable (and related connector), one of which
is used for common return, one for left channel send and the third one for right
channel send.
Optionally, some headphones are provided with a 4-pole cable and connector: two
poles for left channel drive and two poles for right channel drive.
Headphones of the first type can only be driven in single-ended mode, whereas the
amplifier drives one of the wires running to each speaker and the other wires are
connected to the amplifier’s ground.
Headphones of the second type can be driven in balanced mode, in which two
amplifiers drive one wire of each headphone speaker.
The first setup is a low cost manufacturing option as it only requires one stereo
amplifier. If this low cost manufacturing option is used, this severely limits sound
quality (as the two channels signals may partly mix due to the non-zero impedance of
the common return wire. This leads to reduced channel separation and a slight
dynamic loss).
These problems may be reduced by separating the returns to ground, thus improving
the sound quality.
An additional improvement is obtained by “lifting” from the amplifier’s ground the
return wire of each speaker: this can be accomplished, as mentioned earlier in this
manual, by using a bridge amplifier (that is, an amplifier provided with two output
stages operating in push-pull). In this setup, called “balanced” the two speakers
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cannot interfere each other anymore and the best performance may be obtained by
the transducers used.
Despite the common belief, no specific driver technology takes a specific advantage
from balanced drive: any pair of speakers, be they dynamic, electrostatic, electret or
isodynamic, will give better performance when balance-driven.
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8. Technical Specifications
Inputs: ............................................... 2 line level on gold-flashed RCA sockets
Outputs: ............................................ 2 6,35mm (1/4”) stereo jacks
1 4-pin female XLR socket
Preamp out on gold-flashed RCA sockets
Tape out on gold-flashed RCA sockets
Supply input: ..................................... 5.5/2.1mm jack with positive on tip
4-pin male XLR socket for +15V/-15V/+5V
Output voltage: ................................. 8Vrms max (single-ended)
16Vrms max (balanced)
Output power: ................................... 4Wrms p.c. @ 8 Ohm (single-ended)
Input impedance: .............................. 40kOhm
Gain: ................................................. 12dB (single-ended)
18dB (balanced)
SNR: ................................................. 120dB (8Vrms, 1kHz, “A” weighted)
THD+N:............................................. 0,003% (2Vrms, 1kHz)
Volume range ................................... 0dB to -78dB with 1dB steps
Muting ............................................... -20dB
Balance range................................... +/-6dB with 1dB steps
Auto switch-off .................................. 30 to 240 minutes with 30 minutes steps,
or disabled
Power supply: ................................... 15VDC 2A
Power consumption: ......................... 30VA
Size:.................................................. 200x50x200mm (w x h x d)
Weight............................................... 2kg (unit only)
3kg (with packaging)
For technical support please contact your retail dealer or e-mail to:
support@m2tech.biz
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marley
DUAL-DRIVE CLASS-A HEADPHONE AMPLIFIER / PREAMP
M2Tech
www.m2tech.biz
REVISION 1.0 – NOVEMBER 2013
Copyright © 2013, M2Tech Srl
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