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marley 
DUAL-DRIVE CLASS-A HEADPHONE AMPLIFIER / PREAMP 

REVISION 1.0 – NOVEMBER 2013 

 

Copyright © 2013, M2Tech Srl 

25 

M2Tech 

www.m2tech.biz 

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 switch-

off 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.

 

 
 
 
 

All manuals and user guides at all-guides.com

Summary of Contents for Marley

Page 1: ...M2TECH MARLEY DUAL DRIVE CLASS A HEADPHONE AMPLIFIER Preamp USER MANUAL REV 1 0 11 2013 All manuals and user guides at all guides com a l l g u i d e s c o m ...

Page 2: ...marley DUAL DRIVE CLASS A HEADPHONE AMPLIFIER PREAMP REVISION 1 0 NOVEMBER 2013 Copyright 2013 M2Tech Srl 2 M2Tech www m2tech biz All manuals and user guides at all guides com ...

Page 3: ...o 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 pr...

Page 4: ...g 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 ...

Page 5: ...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 dr...

Page 6: ...marley DUAL DRIVE CLASS A HEADPHONE AMPLIFIER PREAMP REVISION 1 0 NOVEMBER 2013 Copyright 2013 M2Tech Srl 6 M2Tech www m2tech biz All manuals and user guides at all guides com a l l g u i d e s c o m ...

Page 7: ... 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 ...

Page 8: ...marley DUAL DRIVE CLASS A HEADPHONE AMPLIFIER PREAMP REVISION 1 0 NOVEMBER 2013 Copyright 2013 M2Tech Srl 8 M2Tech www m2tech biz All manuals and user guides at all guides com ...

Page 9: ... 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 ...

Page 10: ...marley DUAL DRIVE CLASS A HEADPHONE AMPLIFIER PREAMP REVISION 1 0 NOVEMBER 2013 Copyright 2013 M2Tech Srl 10 M2Tech www m2tech biz All manuals and user guides at all guides com ...

Page 11: ... 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...

Page 12: ... www m2tech biz 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 All manuals and user guides at all guides com ...

Page 13: ...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 ind...

Page 14: ... 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 s...

Page 15: ...uts 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 single ended and balanced outputs at the same time Figure 2 7 8 Connect the wall wart jack to the MARLEY s power supply ...

Page 16: ...make this connection with the MARLEY MARLEY MARLEY MARLEY disconnected from any power source and with the MARLEY MARLEY MARLEY 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 All manua...

Page 17: ...hould 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 All manuals and user guides at all guides com ...

Page 18: ...gure 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 VOL 40DB IN 1 Figure 4 VOLA 40D...

Page 19: ...igure 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 c...

Page 20: ...he 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 Sour...

Page 21: ...ected 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 ne...

Page 22: ... 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 ...

Page 23: ...omatically 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 volu...

Page 24: ...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 MARLEY MARLEY MARLEY allows for setting volumes between 0 and 78dB with 1dB steps Volume display only i...

Page 25: ...hes 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 t...

Page 26: ...hen 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...

Page 27: ... 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 chang...

Page 28: ...the button NOTE In the Off status the MARLEY MARLEY MARLEY 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 t...

Page 29: ...econd 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...

Page 30: ...h 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 All manuals and user guides at all guides com ...

Page 31: ...ut 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 consumpt...

Page 32: ...marley DUAL DRIVE CLASS A HEADPHONE AMPLIFIER PREAMP REVISION 1 0 NOVEMBER 2013 Copyright 2013 M2Tech Srl 32 M2Tech www m2tech biz All manuals and user guides at all guides com ...

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