HeadRoom Headphone Amplifier Digital-Analog Converter User Manual

The Micro Amp & DAC

headphone ampliﬁer

& digital-analog converter

Owner’s Manual

Congratulations! You’ve just received the cutest little piece of hard-core

audio hardware known to the world of audiophilia. The Micro Amp and Micro

DAC are jam packed with all the sweet parts, terriﬁc engineering, quality

manufacturing, and years of experience needed to make luscious tunes

bloom in your head. So get out your best headphones, put on your favorite

music, and prepare for the perfect pleasures of personal listening made right

between your ears.

Toll Free: 8 0 0- 8 28 - 81 8 4 Phone: 4 0 6 - 5 8 7 - 9 4 6 6 Fax: 4 0 6 - 58 7- 9 4 8 4

2020 Gilkerson Drive Bozeman, MT 59715 w w w . h e a d p h o n e . c o m

The Micro Amp

The Micro Amp Panel Descriptions

Packing HeadRoom’s mobile electronics module, two nine-volt batteries, and all the knobs and switches you need into an all but bullet proof aluminum enclosure is pushing it a bit, but you won’t care because your head will be thanking you for the lovely tunes.

Volume

Line

Input

Headphone

Out

Crossfeed

Switch

Control

Gain

Switch

Power Source Switch

External Power Input

Thumb Screws

Front Panel

1. Line Input The line input is where you plug in the source. Preferably the Micro

DAC; but it could be the line out of your iRiver or the headphone out of an iPod. You will need a mini-to-mini cable to hook up your Micro Amp.

2. Headphone Out The headphone out is where you plug in your headphones.

There isn’t room for a full sized jack, but this 1/8th inch mini-plug will take the small plug of all 1/8” headphone jacks. We also sell a short ﬂexible Grado 1/4”-1/8” adaptor for your big cans; and you can get a replacable Cardas headphone cable with a mini connector for many types of headphones, call us or consult our website for details.

3. Crossfeed Switch This switch engages the crossfeed circuit. The audio image

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 crossfeed 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.

4. Gain Switch The 3-position Gain Switch accomodates various headphones’

power needs. For instance, the Low Gain setting would be used for in-ear monitors, 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. If have any questions regarding your headphones, feel free to call and ask us.

5. Volume Control You never know where the volume control should be set as

different headphones often have widely different impedances and efﬁciencies, so 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.) You also need to turn the amp OFF or ALL THE WAY DOWN before plugging in or unplugging your headphones to avoid short-circuiting the amp. As you turn the volume control knob clockwise, the volume increases.

6. Power Source Switch Immediately to the right of the volume control is the

power source switch. It will run on either the two internal 9-Volt batteries or an external power supply. If the batteries are in and external supply is attached, the only way you can turn it off is by selecting ‘external’ and then unplugging the connector. We offer two power supplies: the less expensive, lovingly known as “brick”, power supply comes with the amp, the more expensive Desktop Power Supply will give you cleaner juice, and therefore cleaner, more dynamic sound.

Rear Panel

7. External Power Input Connect either your brick or Desktop Power Supply

here.

8. Thumb Screws To change your batteries, unscrew the screws and remove the

rear panel. Orientation of 2 nine-volt batteries is indicated by the illustrations on the rear panel.

The Micro DAC

The unlikely marriage of a well supported Texas Instruments USB sound device chip (to get the S/PDIF signal), Cirrus Logic’s ﬂagship D/A converter, and two 9-Volt batteries bears the fruit of incredibly good sound anywhere you want to set up a personal listening station. Take a tour of the front and rear panels and here’s what you’ll ﬁnd:

Line

Output

Optical/

Coaxial

Digital

Input

USB

Input

Select

Power Source Switch

The Micro DAC Panel Descriptions

Front Panel

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. Don’t forget to check out our Cardas mini to mini cables; they come in many ﬂavors . . . ok, four different lengths.

2. Optical/Coaxial Digital 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.

3. USB Input The USB input gets its signal from a computer: laptop or desk-

top; PC, Mac, or Unix. There aren’t any portable players of any kind that have the ability to talk to an external USB sound device . . . yet.

4. Input Select Switch If you are using both inputs select the one you

want to listen to with this switch.

5. Power Source Switch To the far right is the power source switch. It will

run on either the two internal 9-Volt batteries or an external power supply. If the batteries are in and external supply is attached, the only way you can turn it off is by selecting ‘external DC’ and then unplugging the power supply from the back of the unit. We offer two power supplies: the less expensive version, lovingly known as “brick”, power supply comes with the amp, the more expensive Base Station One will give you cleaner juice, and therefore cleaner, more dynamic sound.

Rear Panel

6. External Power Input Connect either of your power supplies here.

7. Thumb Screws To change your batteries, unscrew the screws and re-

move the rear panel. Orientation of 2 nine volt batteries is indicated by the illustrations on the rear panel.

External Power Input

Thumb Screws

+ 4 hidden pages