G-Rod CBA‐1 Audio Cable MicroAmp Operation Manual

Audio Cable MicroAmp
Model CBA‐1 Operation Manual
G-ROD audio LLC
7151 W. Rivulet Drive
Tucson, AZ 85743
USA
(520) 395‐8436
www.g‐rod.com
Designed and Manufactured in USA
© 2011 G-ROD audio LLC
HOOKING UP THE MICROAMP
The G-ROD Audio Cable MicroAmp is easy to connect
and use – just follow the simple instructions below:
1. Turn down the volume control on your MP3 player
(or other audio source) driving the MicroAmp and also
the volume control on your stereo amplifier.
2. Using an appropriate 3.5mm stereo cable (not pro‐
vided by G-ROD), connect the output of the MicroAmp
to the line input jack of your car stereo, home stereo, or
TV.
3. Using the 3.5mm stereo cable included with your
MicroAmp, connect the input of the MicroAmp to the
headphone jack of your MP3 player (or other audio
source).
4. Using the Micro‐USB power cable included with your
MicroAmp, connect the small end of the cable to the
Micro‐USB jack on the MicroAmp and the large end of
the cable to a standard USB power jack.
For car stereo applications, the USB power jack will be
on a 12V–to–5V USB car power adapter.
For home stereo and TV applications, the USB power
jack will be on a wall‐powered 5V USB power adapter.
For personal computer (PC) applications, the USB
power jack will be a standard USB connector on the PC.
5. Turn on the MP3 player (or other audio source).
MAKE SURE THE VOLUME CONTROL IS TURNED DOWN.
Then turn on the stereo amplifier. MAKE SURE THE
VOLUME CONTROL IS TURNED DOWN.

WARNING!

This device adds 25dB of gain to the audio signal – Up
to 8 times louder! The purpose of the Audio Cable
MicroAmp is to achieve the same listening levels as
normal, with the volume controls on your devices set
lower, reducing noise and distortion and improving
sound quality.
READ BEFORE CONNECTING
Before using the G-ROD MicroAmp, SET THE VOLUME
CONTROLS TO MINIMUM on the audio source head‐
phone jack and on the stereo amplifier. When con‐
nected, set the volume on the MP3 player to 1/3 to 1/2
volume and the volume control on the stereo all the
way down.
NOTE: The CBA‐1 Audio Cable MicroAmp is a preampli‐
fier only, it does not add power to your audio system.
HEARING LOSS
Your ears can begin to suffer permanent hearing loss by
sustained exposure to sounds over 85dB SPL (Sound
Pressure Level).
Be smart – never listen to music at sustained volumes
over 100dB. When listening at louder levels, do so for
no more than 10 minute at a time. Give your ears a 30
minute break before doing it again. Keep your ears
golden!
Micro-USB POWER IN
3.5mm 3.5mm TO
FROM MP3 STEREO AMP
AUDIO AUDIO
IN OUT
OPERATING THE MICROAMP
The G-ROD Audio Cable MicroAmp is very easy to oper‐
ate – simply use the volume controls on the MP3 player
(or other audio source) and the stereo amplifier as
described below.
To avoid overdriving the MicroAmp, set the volume
control on the MP3 player (or other audio source) to
about one third to one half volume, and slowly adjust
the volume control on your stereo amplifier, starting at
fully off, until you get an acceptable volume level.
Experiment with the volume control settings on the
MP3 player and the stereo amplifier to get a balance
between the settings. You should not need to turn the
volume control on the MP3 player up very high. Once
you have a feel for the way the volume controls inter‐
act, choose a balanced setting and enjoy.
If you notice distortion in the sound, turn down the vol‐
ume control on the MP3 player until the distortion goes
away, and use the volume control on the stereo ampli‐
fier to get the volume level you desire.

INTRODUCTION

What is a G-ROD Audio Cable MicroAmp?
The Audio Cable MicroAmp is a voltage amplifying
device that increases the voltage level from low‐imped‐
ance headphone jacks to provide the higher voltage
levels required by the line‐level inputs of stereo amplifi‐
ers. It is an impedance matching audio preamplifier,
designed to match the low output impedance (8‐32
Ohms) of headphone jacks to the high input impedance
(1000 Ohms) of the line inputs on stereo amplifiers.
The Audio Cable MicroAmp adds 25dB of gain to the
output of your audio device (about 8 extra steps on
your volume control). This makes it possible to lower
the volume control settings on your input and output
devices while providing increased sound volume and
clarity.
HOW IT WORKS
The headphone jack outputs on portable audio devices
such as MP3 players are designed to drive headphones
that are relatively low impedance, typically 8 to 32
ohms. The headphone jack output must supply signifi‐
cant current to drive the speakers in the headphones,
but the voltage levels available from these headphone
jacks is limited and typically too low to drive stereo
amplifier line‐level inputs without turning up the vol‐
ume to maximum on the MP3 player. Having to turn
the volume to maximum on the MP3 player forces the
headphone amplifier of the MP3 player into an operat‐
ing mode with very high noise and distortion, making
the sound very unpleasant.
The G-ROD Audio Cable MicroAmp amplifies the volt‐
age level from the MP3 headphone jack, providing a
much larger voltage level to drive the line‐level inputs
of the stereo amplifier. This allows the MP3 player vol‐
ume control to be turned down so the headphone
amplifier is not overdriven and results in much lower
nose and distortion and a cleaner much more enjoy‐
able sound.
The G-ROD MicroAmp is audiophile quality, with speci‐
fications that match those of high‐end audiophile sys‐
tem preamplifiers. It does not use any form of signal
processing to alter the original sound. The MicroAmp
voltage amplifying / impedance matching design
reduces noise and distortion and improves the overall
sound quality.
The MicroAmp boosts signal levels beyond what is
needed to attain the maximum level your audio system
is capable of. OVERDRIVING THE VOLUME OF YOUR
SYSTEM WILL CAUSE DISTORTION AND MAY DAMAGE
YOUR STEREO AMPLFIER, SPEAKERS, OR YOUR HEAR‐
ING.
SUPPLIED ACCESSORIES
1‐ft. right angle Micro‐USB to USB Type A cable
1‐ft. 3.5mm to right angle 3.5mm stereo audio cable
SYSTEM REQUIREMENTS
USB Power – USB jack, 12V–to–5V USB car power
adaptor, Micro‐USB cell phone charger.
Audio Source – 3.5mm stereo headphone jack from
MP3 player or other audio device, laptop and notebook
computers, and portable DVD players.
Stereo Amplifier – Car stereo systems with 3.5mm
external audio (iPod) input jacks (cars from 2006 to
present), after‐market car stereos and CD changers
with audio input jacks, desktop stereo systems, audio‐
phile stereo systems, home entertainment systems,
TVs.

SPECIFICATIONS

Distortion < 0.01%
Signal to noise ratio > 100dB
Gain 25 dB
Nominal Audio Input 31 mV (‐28dBu)
Output 0.775V (0dBu)
Maximum Audio Input 116 mV (‐16dBu)
Output 2.9V (11.5dBu)
Input power 5VDC Micro‐USB
Power consumption 50mW
Dimensions: 2.3" x 1" x 0.5"

TROUBLESHOOTING

NO SOUND
Cause – No USB power
Solution – Check USB power source with another
device
Cause – Connections reversed
Solutions – Verify proper in/out audio cables
DISTORTION
Cause – Overdriving the Input
Solution – Turn down source volume
HUM, BUZZ, CLICKING SOUNDS
Cause – Ground loops
Solution – Unplug charger from input device or use an
isolated power supply for charging input device
G-ROD CUSTOMER SUPPORT
(520) 395‐8436
support@g‐rod.com