Practical Devices XM5 Manuel utilisateur
XM5
Headphone Amplifier
User’s Manual
Thank you, and congratulations on your purchase of the XM5 Portable
Headphone Amplifier
We’ve worked very hard to provide you with what may be one of
the most advanced, feature packed, and best sounding headphone
amplifiers on the market today. The XM5 is designed to be durable, flexible,
easy to use, practical, and above all, sound great. Each unit is carefully
manufactured, and then rigorously tested for performance, durability, and
sound quality.
If you have any questions that are not answered by this manual,
please feel free to send us an email. Enjoy the amp
Yours truly,
James Forest
President & CEO
©2008 Practical Devices Corporation. All rights reserved.
www.practicaldevices.com
A Word About Protecting Your Hearing
:
The most
valuable piece of audio equipment you own are your ears. Smart people protect
their hearing. When using the XM5, or any headphones, get in the habit of
removing the headphones from your ears whenever you:
•
Turn the XM5 on;
•
Connect or disconnect any cables, including the USB cable;
•
Turn your computer off/on/sleep/standby with the USB cable connected;
•
Press the USB select button on the back of the XM5.
•
Anything that may cause a sudden burst of loud sound.
Your only have one set of ears, and you can’t replace them. Always listen to
music at reasonable volume, and most importantly, use good common sense.
PLEASE
READ!
XM5 Block Diagram ....................4
Connecting Your XM5 .................6
USB .............................................7
Power Button Functions ..............8
Crossfeed Controls......................9
Bass, Treble, Gain Boost...........10
75Ω output, Voltmeter................11
Disassembling the Unit..............12
Re-assembling the Unit .............13
Battery Power Systems .............14
Frequently-Asked Questions .....15
Troubleshooting.........................16
Warranty and Guarantee ...........17
Technical Specifications ............18
3
Table of Contents
Crossfeed Enable Switch
IN position: XFeed enabled.
OUT position: XFeed disabled
M5 Block Diagram
Bass +6dB
4
Gain Boost Switch
IN position: +10db extra boost
OUT position: + 0db extra boost
75Ω Switch
IN position: 75Ω output impedance
OUT position: 0Ω output impedance
Power Button
Press button:
1 time = Turn on power for 1 hour
3 times = Turn on power for 3 hours
6 times = Turn on power for 6 hours
7 times = Turn on power forever
2 times = Toggle flashlight mode
5 times = Toggle blue LED dim
Press and HOLD to turn unit off.
Press once to display battery voltage.
For example, if battery is at 8.5 volts,
the amber LED will flash 8, then 5
Main Volume
Blue LED
Indicates
power is on
Amber LED
Flashes battery voltage when Power Button
is pressed.
Low-Battery warning: Flashes a one-flash
warning when the battery is low (below 6.5
volts). Flashes a two-flash warning when the
battery is very low (below 5.2 volts).
Output
Connect to
Headphones
Input
Connect to MP3
player or other
audio source.
Treble +2.5dB
5
M5 Block Diagram, cont.
Amplifier
Chips Buffer
Chips
Power Connector
Used to power and recharge the XM5. Use
only the AC adapter supplied from Practical
Devices.
Note: Before plugging in the AC adapter:
unplug the USB cable, plug in the adapter,
then reconnect the USB cable.
Crossfeed Adjuster
Turn this potentiometer to adjust the amount of
Crossfeed, from near-stereo to 100% mono.
Source Switch
IN position: Source is USB DAC
OUT position: Source is FrontPanel input
USB Connector:
Mates with Mini-USB
type B 5-pin plug.
Interior View:
6
Connecting Your M5
Your headphones can have an impedance of 24 to 600 ohms.
1. Connect your headphones to the output jack.
2. Connect a suitable source to the input jack, as pictured. Sources
may be MP3 or CD players, iPods, or any line-level devices.
Alternatively, you may connect the XM5’s rear-panel USB port. Be
sure to set the rear-panel source-select switch (switch-out selects
front panel input; switch-in selects USB).
7
USB DAC
To use the XM5’s USB DAC, simply connect the XM5 to your computer, using the
included USB cable.
•
The XM5’s RearPanel USB connector takes a “Mini USB Type B 5-pin plug”.
•
You may connect the XM5 through a USB hub, if desired.
•
The XM5 will not recharge from the USB cable.
•
IMPORTANT: If the USB cable is connected, and you want to plug in the AC
adapter: you must 1) unplug the USB cable, 2) plug in the adapter, then 3)
reconnect the USB. Failure to do so can cause USB hang-ups.
Driver Support (Windows P and Windows Vista): Windows XP and Windows
Vista have built-in drivers to support the XM5. The first time you plug in the XM5,
the drivers will automatically install:
You may have to choose the XM5 to be the default audio device (
Start->Settings-
>Control Panel->Sounds and Audio Devices->Audio->Sound playback Default device
).
If your media-playing software (Winamp, Windows Media Player, etc) was running
when you plugged in the XM5, you may have to exit and restart the media-
playing software.
Driver Support (Linux, MAC OS): Most Linux distributions natively support the
XM5, using ALSA. Mac OS X and OS 9 also support the XM5
IMPORTANT: Get in the habit of REMOVING YOUR HEADPHONES when doing such
things as:
•
connecting or disconnecting the USB cable, or
•
Waking your computer up, or putting it to sleep, hibernation, or shutdown
•
Switching the XM5’s RearPanel switch
•
Connecting or disconnecting the XM5’s Line-In connector
Doing so will prevent your ears from being exposed to excessively-loud bumps, thumps,
clicks, or overly-loud music. Smart people protect their hearing
8
Power Button
The power button functions are activated by pressing repeatedly
within a three second window:
1 press: Turn unit on. The XM5 turns off
automatically after one hour.
3 presses: Turn unit on for three hours.
6 presses: Turn unit on for six hours.
7 presses: Turn unit on. The XM5 will not turn itself off.
Press and hold: Turn unit off.
The unit will respond to button presses by flashing the
blue LE once for each hour it will stay on.
Additional power button functions:
2 presses: Toggle flashlight mode (all LEDs on full).
5 presses: Toggle LED dimming.
Power Button Functions
9
CrossFeed Controls
The XM5’s Active Crossfeed circuit simulates the sound
stage of loudspeakers, through your headphones.
•
Press the Switch IN to activate Crossfeed.
•
Leave the button OUT for full stereo operation,
bypassing the Crossfeed circuit entirely.
Use a small screwdriver (Philips or Straightblade) to adjust
the Crossfeed Potentiometer:
•
All the way clockwise to produce a mono signal;
•
All the way counter-clockwise to produce a near-
stereo image.
Why would you want Crossfeed?
Most music is mixed to be
listened to on loudspeakers. The studio technicians mixing the recording
assume there will be alot of crosstalk, since with speakers the listener's left
ear clearly hears the right speaker's output, and vice versa. Thus, most music is mixed
with a very wide stereo soundstage.
With headphones, however, the left ear only hears the left channel, and the right ear
only hears the right channel, with nearly zero crosstalk. This can, for many recordings,
cause the soundstage to appear to be "in the center of your head". Further, some
recordings (early Beatles recordings are infamous for this) have each instrument and
vocal track panned 100% to either left or right, which can almost immediately cause
listener fatigue. Crossfeed corrects this by bleeding some of the left channel into the
right, and vice-versa.
Crossfeed Enable Switch Crossfeed Adjuster
Only works when
switch is enabled.
10
With the volume knob at full, your XM5 will deliver +12dB of gain.
Additionally, you can enable the gain boost switch, which will give you an
extra +10dB of gain, for a total of approximately +22dB.
In order to get the best possible noise floor, you should not enable the Gain
Boost unless:
a) the volume of your headphones is too quiet, and,
b) you have already tried turning up the volume of your source (mp3
player).
Gain Boost
Usually, the Gain Boost is only needed when using headphones which
have an impedance greater than around 150 ohms.
Bass and Treble Boost
You may use the bass and treble boost buttons to give the following
approximate boosts:
Bass Boost: +6dB @ 100Hz
Treble Boost: +3dB @ 10kHz
Frequency response with
Bass Boost enabled
Frequency response with
Treble Boost enabled
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