HeadRoom Micro DAC User manual

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Micro DAC
Digital-Analog Converter
Owner’s Manual
TollFree: 800-828-8184
Phone: [phone]
Fax: [phone]
2020 Gilkerson Drive
Bozeman, MT 59715
www.headphone.com
Congratulations on the purchase of one of the world’s handiest audio prod-
ucts. Able to buffer USB from your computer for low-jitter smoothness; able to
strip S/PDIF digital data from optical or coax inputs in a single ick of a switch;
able to source a sweet analog signal for your favorite headphone or speaker
based back-end …it’s Super Micro DAC! Okay, so we got a bit carried away,
but so will you when your digital music so wonderfully lls that space right
between your ears.
Either way you go, you’re getting the best DAC in Cirrus Logic’s lineup; some
of the nest metal-lm resistors and poly caps money can buy; and a perfectly
lovely way to get great sound without burning up valuable desktop real estate.
But enough of this chatter! Read on, hook up, and bliss out to your music. You
deserve your reward for money well spent!

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The Micro DAC Front Panel
1.
Input selector
switch
2.
Power
Switch
The front panel of the Micro DAC is short, sweet, and elegant; one simple set
of input switches and another power switch along with the HeadRoom logo-
LED are all the grace that front of this simple unit.

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1. Input Selector Switch choose between your digital inputs here. The
input selector switch allows you to have multiple digital sources plugged in to
your Micro DAC all at one time. You can easily switch between your sources
by simply ipping this switch to the corresponding input you’d like to hear;
either USB, coax, or optical. Be sure to turn the volume down before switching
between various inputs until you grow accustomed to any volume level changes
that may occur with varying source impedances.
2. Power Switch When the power is set to ‘on’; the red LED will illuminate
in the center of the HeadRoom logo in the upper left hand corner of the amp.
There is nothing wrong with leaving your amp ‘on’ or ‘off’ for lengthy periods
of time; however we recommed that you unplug your amplier if you’re stor-
ing it for a long period of time.
The Micro DAC Front Panel Descriptions
Included Power Supply

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The Micro DAC Rear Panel
1.
Line
Output
2.
Optical
Input
3.
External
Power
Input
4.
Coaxial
Input
5.
USB
Input
On the back of the unit you will nd a line output, external power input, and
three digital inputs: optical, coaxial, and USB.

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1. Line Output The line out is the best sounding stereo-mini plug out there.
This is the signal source you plug into the input of your headphone amp. You
will need a mini-mini cable to plug from the Micro DAC into the Micro Amp or
other amplier with a line input. HeadRoom sells various mini-mini cables;
we highly recommend one of varying lengths offered by Cardas. You can also
use this output to connect your Micro DAC to another amplier, home stereo
receiver, or home theater system.
2. Optical Input The optical input is the rst of the digital inputs we’ll
discuss on the Micro DAC, and uses your typical Toslink connector. You get
this input signal from the optical output of your player. Not so many portable
audio players have optical outputs, but many portable DVD players and some
hard disk drive players do. Of course, you can get this signal from many pieces
of home equipment.
3. External+/- 15VDC Power Input Plug in your power supply here.
The ‘brick’ power supply is included with the Micro DAC; upon purchase you
will have chosen a voltage appropriate to your country’s voltage requirement,
either 110v (North America, Japan, Singapore and others) or 220v (Europe,
Australia, China, etc). We also recommend the Astrodyne switching power
supply or the larger Desktop Power Supply (both accomodate any country’s
voltage requirement) as available power upgrades, these upgrades are par-
ticularly useful with the Micro DAC. Visit our website for more information
about these power supply upgrades.
4. Coaxial Input The coaxial input is your typical coaxial connector. We rec-
ommend using a 75 ohm digital cable when using the coaxial input. Please
visit our website at headphone.com for various coaxial cables. If your Coaxial
cable is a standard size, you will need a mini adaptor that adapts a full size
coaxial connector to a mini size, they are available for purchase on HeadRoom
website, and are called RCA-Mini Mono adaptor.
5. USB Input The USB input gets its signal from a computer: laptop, desk-
top, or Micro DAC-Mobile PC; PC, Mac, or Unix. Most computers will instantly
recognize the Micro DAC upon plugging it in, but occasionally some users may
need to go into the audio preferences and select the “USB Audio Codec” as
their primary sound device. You also may need to restart your music playing
program (iTunes, Windows Media Player, etc) once the Micro DAC is plugged
in.
The Micro DAC Rear Panel Descriptions

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Micro DAC
• Multiple Digital Inputs
• +/-15V Power Supply
• DC coupled signal path, from input to output
• Discrete emitter follower ouput stage, biased into class A operation (the
Diamond buffer)
• Resistors are low noise, low drift .1% metal lm types
• Local device decoupling with low-ESR, tight tolerance PPS lm capacitors
• Power supply decoupling with ultra low ESR electrolytics
• Shortest signal path possible, PCB routed with high-speed signal integrity
and low noise in mind
• Multi-layer PCB with dedicated, low impedance power and ground layers
Micro DAC Features
upsampling
circuitry
current
regulator
diodes

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Imagine you are listening to a pair of speakers. If you turn off the left speaker,
both ears hear the sound from the right speaker. But because the left ear is
slight farther away than the right ear, it hears the speaker’s sound slightly
after the right ear; about 300 microSeconds. This time difference is called the
“inter-aural time difference” and it is the main thing your brain listens for in
order to tell where to place sound left-to-right.
But in headphones if you turn off the left channel, only the right ear hears the
sound. In headphones, if there is any sound that is only in the left channel, or
only in the right channel, then only that ear hears the sound. This is not natu-
ral, and you brain becomes fatigued trying to gure out where sound is com-
ing from when only one ear is hearing it. This tends to create an audio image
that is a blob on the left, blob on the right and a blob in the middle.
HeadRoom ampliers cure the problem by allowing you to cross-feed a little
of the left and right channels across to each other through a short time delay
using the crossfeed switch. The usefulness of the circuit varies depending on
what type of recording you are listening to; mono and binaural recordings
need no processor at all. Old studio recordings that have instruments panned
hard left or right, benet greatly from the processor. Live and classical record-
ings miked from a distance benet somewhat less, and can often be listened
to without the processor quite comfortably.
Plain
Headphones
With
HeadRoom
The crossfeed switch in
HeadRoom ampliers al-
low you to cross-feed a
little of the left and right
channels across to eacho-
ther through a short time
delay.
Far ear
hears
slight delay.
Near ear
hears sound
rst.
30 degrees
off axis
What is the HeadRoom Crossfeed?

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+/- 15 VDC power input
+
-
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-
The most convenient and common way to get a high quality signal out of your com-
puter is with USB output. (If you have optical or coaxial outputs on your machine, then
skip to the next section.) Simply plug a USB cable into your computer, and plug the
smaller end into the back of the amp. In most cases your computer will instantly
recognize the amplier, but you will need to
restart your music management program. If
your computer does not recognize the de-
vice, restart; if it still is not recognized, you
may need to go into your control panel/audio
devices or system preferences/sound output
and select ‘USB Audio Codec’ as your default
audio device.
- Switch the Digital Input Selector Switch
to‘USB’.
Connecting Your Micro DAC
USB Input
USB cable
Connecting to your Computer:
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+/- 15 VDC power input
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Optical cable
Optical Input
To a portable DVD player with Optical Output:
You will need an appropriate optical cable, visit headphone.com to purchase a cable.
Plug one end into your source and connect the other end into the appropriate input
on the back of the amp. (Some DVD players may require you to turn on or activate the
optical output.)
- Switch the Digital Input Selector Switch to ‘optical’.
Coaxial cable
RCA- Mini
Mono adaptor
To a Home CD player with a Coaxial output:
You will need an appropriate coaxial cable, visit headphone.com to purchase a cable.
Plug one end into your source and connect the other end into the appropriate input
on the back of the amp. If your Coaxial cable is a standard size, you will need a mini
adaptor that adapts a full size coaxial connector to a mini size, they are available for
purchase on HeadRoom website, and are called RCA-Mini Mono adaptor.
- Switch the Digital Input Selector Switch to ‘coaxial’.
Home CD player
Coaxial input
Optical
output
USB Out
Coax Out

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+/- 15 VDC power input
+
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Connecting your Micro DAC to an Amp
Plug the mini-to-mini cable
into the line input of the Amp
and line output of the DAC.
Connecting Micro DAC to Micro Amp:
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m
p
volume
line input headphone
output
power
off
crossfeed
battery
external
gain
on
medium
high
low
Headphone output
mini-mini
cable
Your Micro DAC should be used with a headphone amp to properly drive your head-
phones with authority. HeadRoom’s Micro Amp is designed to be used with the Micro
DAC, but any amplier with a line input will follow these same instructions.
Micro DAC
Micro Amp
Connecting Micro DAC to Amp with RCA Inputs:
If you are using a different amp that has a line input, simply follow the instructions
above. If you are using a headphone amp that provides RCA inputs, then you will need
a mini-RCA cable. Plug the mini end into the output of the Micro DAC, and RCA inputs
into the back of the amp (as always, red or ‘R’ denotes right channel).
Line Input
Line Output
Micro DAC
Mini-RCA cable
Headphone amp
RCA
Inputs
Line Output
You can connect any 1/8” (mini) headphone plug into the heaphone output of your
Micro Amp. (An adaptor is needed if your headphones are terminated to a 1/4” plug.)
Connecting headphones to Micro Amp:

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30 Day Guaranty & Warranty
HeadRoom 30 Day Guaranty
Unless specically stated otherwise, all HeadRoom purchases come with a
30-day satisfaction guaranty in order to give you the opportunity to evaluate
your purchases. We’re happy to provide you with the opportunity to refund or
exchange your product, but to keep costs down we do have a few conditions.
Products must be returned to us within 30 days of the date you receive the
product. So make sure you try your purchase out right away! Products must
be in “as-new” condition. This means that they’re in pristine cosmetic condi-
tion, functioning perfectly, and include ALL materials (plastic bags, warranty
cards, tie wraps, etc). In other words, please send products back exactly as
you received them. If a product is returned within the 30-day return period,
but is not in “as-new” condition, we will charge you a 15% restocking fee plus
any labor and materials required to return the product to “as-new” condition.
Sorry, but after your 30 day trial, products are no longer exchangeable or re-
fundable.
If you’re having trouble with a headphone amp or system, please contact us
rst to troubleshoot the problem. You can email Sales, (sales@headphone.
com) or call 800.828.8184. If we can x it while you’ve still got the product,
everyone’s happy!
Micro DAC Warranty:
The HeadRoom Micro DAC and are warrantied for two years. If anytime within
the rst two years of your purchase you have a problem with your Micro Prod-
ucts, you can return it for repairs under the terms of our 30 Day Guaranty.
HeadRoom is the only authorized service center for HeadRoom products, ei-
ther in or out of warranty. If a unit is under warranty, there is no cost for the
repair labor, parts, or shipping from HeadRoom back to you (i.e., You’re re-
sponsible for paying the shipping charges to get the product to us).
Out of Warranty Repairs
If you have an older HeadRoom amp that is out of warranty, call us at
800.828.8184 ext.104 or email [e-mail] to troubleshoot the
problem with our Service Department. Upgrades fees are calculated by labor
and parts costs. HeadRoom’s non-warranty repair rate is $100 per hour (billed
in 1/2 hour increments) plus parts. If the cost of the repair is over $100, we
will call you with an estimate. Repairs are conducted only on HeadRoom prod-
ucts. When we receive the equipment, we will initiate repairs and upgrades
within 1-2 weeks and return the unit to you. You are responsible for shipping
costs to and from HeadRoom for all non-warranty repair items.

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Exchanges & Returns
Equipment Exchanges
If you would like to exchange your purchase for another item, you have two
options. You can simply purchase the item you want, and send the item you
don’t want back for refund within 30 days of the original purchase (don’t for-
get to ll out the back of the Return & Exchange card and include it with your
return). We will refund your credit card after we receive the item. Or, you can
send your product back as an exchange, and indicate the product you would
like on the Return card. We will adjust your credit card accordingly and ship
you the new item. Replacement products are shipped to you as soon as pos-
sible, typically within 3-5 days provided the replacement item is in stock.
Defective Equipment Exchanges
In the uncommon event of receiving a defective product, contact us and we
will ship out a replacement product to you at no cost as soon as possible,
typically within 3-5 days provided the replacement item is in stock. You will
receive the replacement item along with a return shipping label and a card to
include with the defective item to return to HeadRoom. Important: Fill in your
name and original invoice number of your order on the card and return the
item to HeadRoom within 2 weeks. If we have not received the product after 2
weeks (allowing shipping time) we will charge your credit card the amount of
the defective item. Please understand that we enforce this policy as an incen-
tive for customers to get defective equipment back to us as soon as possible.
Shipping Products back to HeadRoom
Please ship products back in the original shipping box (or another that is com-
parable); please don’t send headphones back in JUST the headphone box,
as it’s a sure bet that they will no longer be in “as-new” condition when we
receive them! We HIGHLY recommend that you ship returns using an insured
and “signature required” delivery method—we can’t be responsible for lost or
damaged packages. Finally, don’t forget to include the completed Return &
Exchange card and WRITE YOUR NAME on the outside of the box!
Return Products to:
HeadRoom
Attn: Returns
2020 Gilkerson Drive
Bozeman, MT 59715
Contact Us:
www.headphone.com
Toll Free: 800-828-8184
Phone: [phone]
Fax: [phone]

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TollFree: 800-828-8184
Phone: [phone]
Fax: [phone]
2020 Gilkerson Drive
Bozeman, MT 59715
www.headphone.com
Contacting HeadRoom
A Word About
Your Hearing
People have a natural tendency to listen to music at much louder levels with
headphones than they would with speakers. To avoid permanent hearing
damage, it’s important to be careful not to listen at extremely loud levels (or
to listen for too long at moderately loud levels). Because HeadRoom amps
need to be able to drive even the most inefcient dynamic headphones to sat-
isfactory listening levels, they are also able to drive headphones of average
or higher efciencies to extremely high levels. As a result, even though the
volume control on your HeadRoom amp may appear to be set to a low level,
you may not be listening at a safe level. Generally speaking, when listening
to headphones you should only turn up the volume to the point at which the
sound isn’t too quiet.
As a general rule, sound pressure levels under 80 decibels will not damage
hearing, even if experienced continually. On the other hand, anything over
100 decibels may cause permanent damage very quickly. Sustained exposure
to sound pressure levels anywhere in between can also be damaging —the
louder the sound, the shorter the time required to cause permanent damage.
Just to drive this message home, here’s a bit of information about hearing
damage. The most common type of damage caused by prolonged or exces-
sively loud sound is called tinnitus. It manifests itself as a sustained buzzing
and/or ringing in the ears, and can become a permanent condition.
If you nd that your ears are ringing or that there is a sensation of pressure or
fatigue, your body is trying to tell you that your ears need a break. Give them
a rest for a few days (or until they feel fresh). If you ignore these symptoms,
you’re risking permanent hearing damage.
In addition, don’t fool yourself into thinking that you either have full-blown
tinnitus or you don’t have it at all—there are different degrees of hearing dam-
age. For example, you might have a mild case where you only notice ringing
in your ears in the quiet of your bedroom at night. However, once you have a
slight case of tinnitus, your ears are much more susceptible to further dam-
age. So if you do experience mild symptoms, it’s important to be much more
careful about your exposure to loud sounds.
Sorry to sound so sobering, but a lifetime of musical enjoyment requires ears
in tiptop shape. Now that we’ve told you to be careful, don’t blame us if you
blow it. If you have any more questions about hearing damage, call a doctor.