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Introduction _
The Mapletree Audio Design
Ear+ HD
Super II
Stereo Headphone Amplifier represents
a high performance development of the
Ear+
family. The use of a high capacity power
supply provides increased power output and lower driving impedance employing widely
available EL84 output tubes and 12AX7/5751 drivers. The separate power supply chassis
allows flexibility in positioning each unit and reduces the heat seen by components in the
main amplifier chassis. Premium components include Tantalum film resistors in the
SRPP driver stage and an Alps volume control.
Input/Output Connections______
The standard IEC line cord is attached to the receptacle on the rear panel of the
Ear+ HD
Super II
power supply. It is compatible with a 115-125 VAC line with a frequency of 50–
60 Hz. The third pin is connected to the power supply chassis. A 1A/250 V fuse provides
primary protection for the power supply. It is located under the chassis and can be
accessed by removing the bottom cover of the power supply
with the unit unplugged and
waiting 1 minute after powering off.
Under normal conditions, it should not be necessary
to replace the fuse. If power fails to come on, you can check the fuse and replace with a
spare if necessary. If the fuse blows a second time, you should not try to operate the unit.
Contact Mapletree Audio Design for information regarding service.
The power supply is connected to the amplifier chassis with the supplied power
interconnect cord.
Never power on the power supply without making this connection
. The
two chassis may be stacked or separated as permitted by the power interconnect cord.
The power switch is located on the front panel of the power supply. The LED pilot light
indicates the power on condition. It is powered by the heater supply voltage so is an
indication that power is being supplied to the tube filaments. It takes about 30 seconds for
the tubes to reach operating temperature ready for use.
