HeadRoom Desktop & Ultra Desktop Amp User manual

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TollFree: 800-828-8184
Phone: [phone]
Fax: [phone]
2020 Gilkerson Drive
Bozeman, MT 59715
www.headphone.com
HeadRoom Desktop &
Ultra Desktop Amp
headphone amplier
Owner’s Manual
There’s no sweeter spot in the HeadRoom line-up (other than the
one it will make in your head) Than the Desktop or Ultra Desktop
Amp. This dedicated reference headphone amplier will easily
nd a small nook on your workstation or nightstand, allowing you
to congure it as the perfect pre-amp interface for your world of
analog or digital media and perfectly ll the musical space right
between your ears.

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2
Front Panel
Panel Descriptions
1.
power
switch
2.
headphone
outputs
3.
rear
output
switch 5.
crossfeed
7.
volume
control
The Desktop & Ultra Desktop Amp
1. Power Switch Turn the switch up to turn your Desktop Amp on. The
green LED will illuminute in the center of the HeadRoom logo in the upper left
hand corner of the amp.
2. Headphone Ouputs The headphone out is where you plug in your
headphones. The Desktop Amp is equipped with a 1/4” jack as well as an
1/8” jack, to accomodate various types of headphones.
3. Rear Output Switch The Rear Output Switch mutes or ennables the au-
dio signal. If you are using the amp as a pre-amp, or to listen to self-powered
speakers connected to the Desktop Ultra Amp turn the switch on. If you are
only listening to headphones, turn the switch off.
4. Brightness Switch The Brightness Switch is used to compensate for
the slightly warming action of the processor. In the center position there is no
lter in the circuit; generally this is preferred. But if you feel the processor is
causing too much bass or blurring of the central image, a mild high frequency
boost lter can be turned on. The “lter 1” setting accentuates the highs at
about 3 kHz; with the “lter 2” setting the lter starts an octave earlier and
catches some of the upper mids. Basically, set it to whatever sounds best to
you.
5. Crossfeed Switch This switch engages the crossfeed circuit. Audio im-
aging on headphones is often not very good; typically the image is a blob on
the left, a blob on the right, and a blob in the middle. The HeadRoom cross-
feed provides the natural acoustic cross-feed normally heard at the left and
right ear as heard from the left and right speaker. Adding back the normally
occurring cross-feed signal gives your brain enough information to build the
stable and natural audio image needed to have a quality listening experience.
See pg.8 for more info on the HeadRoom crossfeed.
6. Gain Switch The 3-position Gain Switch accomodates various head-
phones’ power needs. For instance, the Low Gain setting would be used for
ear canal headphones, allowing a larger range on the volume control pot.
Experiementing with your headphones and the gain switch may help you to
determine which setting you prefer.
7. Volume Control As you turn the volume control knob clockwise, the
volume increases. Be sure to turn the amp OFF or ALL THE WAY DOWN before
plugging in or unplugging your headphones to avoid a potential short-circuit-
ing the amp. The volume control setting wcan vary greatly as different head-
phones often have widely different impedances and efciencies. Use your
ears to choose your listening level, not the level on the dial. (We recommend
you choose a moderate level so as not to blow out your ears.)
4.
brightness 6.
gain
switch

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The Desktop & Ultra Desktop Rear Panel
1. Analog Input Selector You may want to plug more than one analog
source into your Desktop Amp. Whether you are using one input or both, you
will need to indicate which analog inputs you want to listen to by choosing
either ‘1’ or ‘2’ with the analog input selector.
2. Analog Inputs There are two sets of analog inputs, both are RCA in-
puts, with the top connector being ‘left’ and the bottom connector ‘right’. The
left-most column is ‘input 1’ and the middle colum is ‘input 2’. The analog
inputs is where you will plug in your non-digital source, such as a stationary
or portable CD player. If your player has an 1/8” line out plug, you will use
a portable cable (mini-RCA); if it has an RCA out (left and right) then you will
use a link interconnect (RCA -RCA). See the ‘cables’ area in our website to
purchase some of these cables.
3. Analog Output If you want to use your Desktop Amp as a preamplier,
plug your outputs into a powered amplier or powered speakers.
4. +/- 15VDC Power Input Plug in your power supply here. The ‘brick’
power supply included with the Desktop amp, as well as the Desktop Power
Supply, will use this connector. See pg 9 for more info on the Desktop Power
Supply upgrade.
5. Source Selector When using the DAC, you will need to choose whether you
are using a digital input or an analog input. The source selector switch allows you to
have both digital and analog sources connected at the same time, and you may change
between the two with a simple ip of this switch.
6. Digital Input Selector When using the DAC, the digital input selector allows
you to choose which digital input you would like to listen to.
7. USB Input The USB input gets its signal from a computer: laptop or desktop;
PC, Mac, or Unix.
8. Coaxial input The coaxial input is your typical coaxial connector. We recom-
mend using a 75 ohm digital cable when using the coaxial input.
9. Optical Input The optical input is 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 anymore (call or check our web site for recommendations), 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.
Desktop & Ultra Desktop Digital-Analog Convertor
8.
coaxial input
4.
+/- 15
VDC
power
input
1.
analog
input
selector
9.
optical input
5.
source selector
6.
digital input
selector
7. USB input
2.
analog
inputs
3.
analog
output
5. 6.
7.
9.
8.
DAC (see pg.5)
Desktop DAC
The Desktop Amp includes HeadRoom’s Home DAC. HeadRoom’s Desktop DAC option
starts to become a very seriously impressive digital-to-analog converter: not only does
it use the agship Cirrus Logic CS4398 DAC, it also uses the hyper-spendy but oh-so-
sweet-sounding Burr-Brown OPA627 op-amps in constant-current “Class-A” bias as
output stage devices. The result is the kind of fully transparent and liquid audio clarity
usually found in multi-thousand dollar upscale CD players but at a mere fraction of
their cost.
Ultra Desktop DAC
The Ultra Desktop DAC is an apostolic work of digital upsampling art dressed in gold
& black. These four-layer, gold-coated, double-copper tracing circuit boards are cov-
ered edge to edge with the best parts serious audiophile money can buy, and right in
the middle of it lies an Analog Devices AD1896 192kHz Stereo Asynchronous Sample
Rate Converter. WHAT?!... Simply a screaming miniaturized gizmo that up-converts any
incoming digital audio signal into an ultra high speed, high resolution digital signal
without relying on the incoming clock timing, and then down-converts it into the slow-
er 192kHz word stream while interpolating (to get rid of digital ‘haze’) and re-clocking
(to get rid of jitter) before sending the data off to the DAC stage.

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How to Connect Your Desktop & Ultra Desktop Amp
How to Connect your Desktop & Ultra Desktop Amp
Desktop Power Supply
Connecting the Desktop Power Supply
The Desktop Power Supply is a power supply upgrade
available for purchase on our website. To connect the
Desktop Power Supply, you will need a power cable
with 5 pin terminations on either side(included with
DPS purchase.) Connect the +/- 15VDC power input
on the Desktop Amp to one of the power outputs on
the back of the Desktop Power Supply. Plug the pow-
er cord into the power entry module. To learn more
about the Desktop Power Supply see page 9.
115V
#2 To a home CD player or other Analog Sources via RCA outputs
#1 To a portable player via Headphone jack or line out.
If your source has RCA outputs, an RCA to RCA interconnect cable will connect the Desktop.
Plug the RCA inputs into the back of the Desktop Amp, and connect the other end to the line
output of your analog source. If your source only has a line out output or a headphone jack,
then go up to #1. If your CD player has digital outputs, skip to the next page.
- Switch the Source Selector Switch to analog.
All hard drive players provide a headphone jack.* An RCA to Mini Cable will allow you to
connect the headphone jack/line out of your player into the RCA inputs on the Desktop.
Choose analog input set 1 or 2, and connect the RCA inputs. Be sure to note that as al-
ways, red or ‘R’, designates right channel. Switch the Source Selector Switch to analog.
*Use line out if your player has it. Line out bypasses the player’s volume control completely; use the
amp’s instead.
RCA Inputs
Interconnect Cable
RCA Mini Cable
Headphone Jack
RCA
Inputs
RCA Outputs
#4 With DAC*: To your Computer or other digital source via USB,
coaxial, or optical output
The most convenient and common way to get a high quality signal out of your computer 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 may need to restart your music management program. If your computer does
not recognize the device, 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 Source Selector Switch to ‘digital’.
- Switch the Digital Input Selector Switch to‘USB’.
To A CD or other player with Optical/Coaxial outputs:
Connecting to your Computer:
You will need an appropriate coaxial or 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.
- Switch the Source Selector Switch to ‘digital’.
- Switch the Digital Input Selector Switch to ‘coaxial’ or ‘optical’.
*Didn’t choose the DAC option with your Desktop Amp? You can send yours in to be upgraded
with our Upgrade program. See headphone.com for details.
Optical Cable
USB Cable
USB
USB Input
Optical Input
optical
RCA
Outputs
Interconnect Cable
RCA Inputs
Most self-powered speakers have RCA inputs, in which case you will use an interconnect
cable to attach to the Desktop Amp. Attach the RCA cables to the RCA outputs on the rear of
the Desktop Amp. Plug the other end into the back of your speakers.
Switch the Rear Output Switch to ‘on’ to listen to your speakers, or switch it to ‘off’ to listen
to your headphones.
#3 Using Self Powered Speakers with the Desktop coaxial
Coaxial Input Coaxial Cable

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Astrodyne Power Supply
Power Supply & Power Supply Upgrades
What is The HeadRoom Crossfeed?
The Desktop Power Supply (DPS) is available as an upgrade. All HeadRoom amps come
with a surprisingly good, but still inexpensive, power supply. Any audiophile will tell
you that the power supply is as, or almost as important as the audio electronics them-
selves. This is true, and the Desktop Supply will help you get every last drop of per-
formance out of the amp you buy. Maximum current output before a potential loss in
audio quality is 500 mA. For the best performance, we recommend one dedicated DPS
for each headphone amp.
Included with the Ultra Desktop Amp is the Astrodyne power supply, an upgraded sup-
ply to accommodate for the demanding Max-level electronics and DAC. We also rec-
ommend the Astrodyne as an excellent, budget-friendly power upgrade for the stan-
dard Desktop Amp. The Astrodyne is a switching-voltage supply, so it may be used
in any country. The Astrodyne provides clean, quiet, robust current on demand, and
shows nice performance gains over the linear regulated AC wallwarts included with
the Desktop Amp.
ground lift
switch
power entry
module
power outputs
Power Entry Module The Power Entry Module is where the Power Supply plugs
into the wall. The power entry module can also be easily changed into other common
international voltages. The red window box on the power entry module indicates the
current voltage setting of your amplier. You can easily switch the voltage between
115 VAC and 230 VAC by carefully opening the power receptacle window housing, then
simply slide out the receptacle and reinsert it facing the opposite way until the desired
voltage clearly shows through the power module window box.
Ground Lift The Ground Lift seperates the audio signal ground from the power sup-
ply ground. Usually, you will want the Ground Lift Switch to be set to ‘normal’, but if
you hear a slight buzzing noise in your system, then turn it to ‘oat’.
Power Outputs There are 6 power outputs on the Desktop Power Supply, and is ap-
propriate for use with any of the HeadRoom Desktop or Micro Lines of amps and DACs.
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
natural, and you brain becomes fatigued trying to gure out where sound is
coming from when only one ear is hearing it. This tends to create an audio im-
age 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 processor 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
Desktop Power Supply

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Exchanges & Returns
Warranty Information
HeadRoom Manufactured Products under Warranty:
The Desktop Amp & Ultra Desktop Amp are warrantied for two years. If any-
time within the rst two years of your purchase you have a problem with your
Desktop Amp, you can return it for repairs under the terms of our Warranty.
Visit our website for details about warranting your Desktop, or give us a call
at 800.828.8184, and we will trouble shoot the problem, and if necessary
authorize a repair.
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 servic[email protected] 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.
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!
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]
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
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!
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.

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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.