Woo Audio WA7 Fireflies User manual

©2013WOOAUDIOtmInc.Allrightsreserved.www.wooaudio.comRev1.2.April,20131
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WOO AUDIO WA7 Fireflies
Pure Class-A Single-ended Vacuum Tube Headphone Amplifier
&
32-Bit/192kHz Digital to Analog Convertor
Owner’s Manual
Please review this manual before operating your WOO AUDIO™ product.

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Important Safety Information
CAUTION: Amplifiers are shipped without the vacuum tubes
installed. The end user must install the tubes, taking great care to
install them correctly in the appropriate sockets. Incorrect
installation will result in serious damage not covered by the
warranty.
Turn off immediately in the event of malfunction!
Should you notice smoke or an unusual smell coming from the
equipment, turn it off immediately. Continued operation could
result in injury.
Do not disassemble
The unit contains high voltage circuitry. Touching the amplifier’s
internal parts may result in injury. In the event of malfunction.
the product should be repaired only by a qualified technician.
Keep out of children
Failure to observe this precaution could result in injury
WARNING: Failure to follow these instructions could result in
fire, electric shock, or other injury or damage.

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Table of Contents

IMPORTANT SAFETY INFORMATION 2
TABLE OF CONTENTS 3
OVERVIEW 4
GETTING STARTED 6
QUICK INSTALLATION 9
OPERATIONS 12
FAQ - FREQUENTLY ASKED QUESTIONS 13
WARRANTY AND SERVICE 14
PRODUCT SPECIFICATION 15
REVIEWS 16
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Overview
The WOO Audio WA7 “Fireflies” Amp/DAC is a combination of high performance
vacuum tube headphone amplifier with a built-in USB Digital-to-Analog Converter. It
employs a pure tube design, utilizing 6C45 tubes in a class-A, single-ended topology,
with transformer coupled outputs. No semi-conductors used in the entire signal path.
The D-A converter is designed to be capable of up to 32-bit/192k sampling rates. Pure
data integrity is maintained while it is transmitted via standard high speed USB 2.0
interface operating in asynchronous mode.
The high quality construction features include a pair of Nickel Alloy core output
transformers, all-aluminum chassis with no screws visible from any viewing angles, a
linear external power supply for amplification circuitries, a custom built toroidal power
transformer, and multi-layer military grade PCBs.
The dedicated port for in-ear-monitors carries a full range of volume controls ensuring
minimal noise. Despite its incredibly compact size, “Fireflies” is a power-house with the
capacity to drive almost any demanding audiophile headphones. To accommodate
different system setup needs, “Fireflies” can also be used as a stand-alone D-A
Converter.

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Features:
oHandmade output transformer with Nickel Alloy core
o32-Bit, 192kHz high resolution playback
oUltra-low jitter USB 2.0 runs on Asynchronous mode
oHigh and low impedance output facilitated via toggle switch on back panel
oOpen load protection will automatically engage to prevent the amp from damaging when
no headphones are plugged in
oMulti-functional switch for USB input, RCA input, and RCA output via D-A.
oThe RCA connectors can be used either as RCA analog inputs or USB DAC line-out
outputs.
oAll-aluminum chassis with no screws visible from any viewing angles
oHigh clarity tube protection glass
oMulti-layer military grade PCBs
oCustomized driver for Windows Vista/XP/7/8
oUSB Audio Class 2.0 is natively supported by Apple OS X version 10.6.4 and above
without installing driver

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Getting Started
What’s in the box?
①Umbilical Power Cord
②Chamois Polishing Cloth for glass and metal cleaning
③External Power Supply
④Tube Protection Glass
⑤WA7 Fireflies Amplifier
⑥6C45 Matched Pair Tubes
⑤
⑥
* USB and inter-connection
cables are not included.
①②
③
④

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Front Panel
Top Panel
Back Panel
7
8 9
⑦Volume control for headphone outputs
⑧3.5mm or 1/8” mini In-Ear-Monitors
headphone jack
⑨6.35mm or 1/4"headphone jack
⑩Tube sockets for 6C45 vacuum tubes
Please
p
a
y
close attention to vacuum
tube installation alignment marks!
⑪USB 2.0 digital input
⑫RCA analog input
⑬Input-output switch
RCA –RCA analog input
USB – USB 2.0 digital input
D/A – Digital to Analog output via RCA
⑭High and low headphone impedance
switch
HI-Z – High impedance
LO-Z – Low impedance
⑮Umbilical power cord socket (male)
⑯Power switch
I – ON
O - OFF
The RCA connectors can be used
either as RCA analog inputs or USB
DAC RCA line-out outputs.
11
10
12
16
15
14
13

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External Power Supply
DC power connection
Connections
The WA7 Firflies can be connected in one of the following ways.
Computer
RCA
⑪Umbilical cord socket (female)
⑫Power LED light
11
12
13
14
⑪AC power inlet
⑫Fuse box
slow blow fuse, 400mA@115V or
200mA@230V
RCA line-out to
active monitors
External Power Suppl
y
AC power connection
A
B
C
USB 2.0
CD player or analog source
RCA
USB 2.0
Digital-to-Analog Convertor
Computer
RCA
line-out to
power amp
IEMs Full-sized
headphones

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Quick Installation
Installing tubes
Umbilical Power Cord Installation
20
Ali
g
n the tube in
the tube socket
according to the
RED arrows
Hold the tube
firmly, slowly
inserting it down
into the socket.
Care must be
taken to only
apply force
perpendicular to
the tube socket;
never insert it at
an angle. Apply a
slight rocking
motion for the
tube which is
harder to insert;
but, never apply
circular motion.
Connectin
g
the Am
p
lifier unit
Align the female plug to the DC input
connector. The “arrow” marking on the plug
should face up when it is properly oriented.
Insert the plug into the socket and turn the
locking ring on the plug until fully tightened.
Connectin
g
the Power Su
pp
l
y
unit
Align the male plug to the DC input
connector. The arrow marking on the plug
should face up when it is properly oriented.
Insert the plug into the socket and turn the
locking ring on the plug until fully tightened.

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Installing the AC power cord (customer supplied):
Plug the power cord into the AC inlet; see ⑬in the above diagram. The AC inlet socket is a standard IEC
type. You will needto obtain the correct type for your region if it not supplied with your order.
Installing Tube Protection Glass:
Do not hit the tubes by the glass. The glass is heavy. Handle with both hands.
Powering Up
To power up on the WA7 Fireflies, flip the power switch ⑯to the “I”position. The LED on the
power supply will lit. Vacuum tubes should lit at the same time.
U.S.
European
U.K.



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Using the Asynchronous USB 2.0 port:
The WA7 Fireflies offers a USB 2.0 port ⑪,refer to the above diagram, which is compatible with
Windows or Mac OS computer.
Installing the USB driver
*These steps only apply for Windows 7.
1. Plug in the USB 2.0 cable to the WA7 Fireflies and your computer.
2. Install the WA7 Fireflies Driver from the downloaded file from
http://www.wooaudio.com/drivers/wa7-fireflies-driver-1.01.zip
3. Unzip the downloaded file. Locate setup.exe file and run it.
4. Follow on-screen instruction to complete the installation. Windows restart may be
required.
5. Set USBSpeakers as your default audio output.
Go to My Computer -> Control Panel -> Hardware and Sounds -> Sounds
-> Click USB Speakers -> Click Set Default
6. Now you're ready to enjoy music from your computer.
Configuring media player
TIPS: It is strongly recommended to use a media player that supports ASIO output
mode for the highest playback quality.
Changing Output mode
Example is given for JRiver Media Center.
IMPORTANT: In JRiver Media Center, disable “Use large hardware buffers” option by
unchecking the box. Buffering error will occur if this option is enable.
Tools -> Options -> Audio Output -> Output mode -> select ASIO
Tools -> Options -> Audio Output -> Output mode settings -> uncheck the box
below

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Operations
NOTE: Only one headphone output is operational at a time. When both headphone
jacks are plugged in, only the ¼” output is operational.
DO NOT
oTurn on the amp before properly installing ALL tubes and power supply.
oBlock vent holes of the power supply.
oUse tubes that are not approved by Woo Audio.
oAlign the male plug to the DC input connector. The arrow marking on the plug
should face up when it is properly oriented. Insert the plug into the socket and
turn the locking ring on the plug until fully tightened.
oRemove any tubes or the umbilical power cord while the amp is operating.
oTouch tubes (they are extremely hot) after warm-up.
oLeave the amp running unattended. (We suggest a maximum of 8 hours of
continuous use, allowing the tubes time to cool before using again)
DO
oPlace the amp away from any wireless or frequency-emitting devices such as
mobile phones, PDAs and radios, to avoid noise interference.
oKeep away from water or excessive moisture.
oTurn off the amp if its sound is abnormal.
oAllow a minimum of 2 inches of air clearance for heat dissipation.
oAllow approximately 3 minutes of warm-up.
oAllow the tubes to cool down before replacing them.

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FAQ - Frequently Asked Questions
Computer cannot find the WA7 Fireflies USB DAC.
oCheck USB cable connection and make sure the cable is USB 2.0 compatible.
oSee “Installing USB driver” section for configuration.
No sound is coming out of the headphone jack.
oCheck you have selected the correct position of the Input-Output switch. Check input connection.
Check computer USB output setting if USB input is used.
No sound is coming out of the mini headphone jack.
oOnly one headphone is operational at a time. Disconnect headphones from the ¼” jack to enable
output of the mini phone jack.
There is static noise, or one channel is dropping out.
oRe-seat all tubes. Make sure that all tubes are securely installed.
The LED does not light.
First check if the AC cord is installed. Next, check if the umbilical cord is securely attached between the
amp and the power supply. If the fuse is burnt, see the following instruction on how to replace a fuse. The
fuse type is 400mA@115V or 200mA@230V, slow blow type.


Insert a small flat
screwdriver into the
fuse door located on
the AC inlet.
Pull the fuse door
to open it.
The fuse holder
may be released
from the AC inlet.
Replace the burnt
fuse with a new one


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Warranty and Service
Woo Audio warrants this product free from defects in materials and workmanship for
one (1) year from the original date of purchase. The tubes are warranted for 30 days
unless otherwise stated. In the event that your Woo Audio product requires servicing,
please contact us directly to receive return instructions. Please do not discard original
packing materials. If for any reason, the equipment is to be shipped back to Woo Audio,
please use the original packaging, including a copy of sales purchase documents and a
detailed explanation of the problem(s).
Send service inquiry to [e-mail]
Any modification not authorized by WOO AUDIO will void this warranty.

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Product Specification
Model: WA7 Fireflies
Headphone amp design Single-ended, class-A, transformers output
Power supply Linear external high-performance power supply
Tubes used One matched pair of 6C45, one tube per channel
USB receiving chipset: C-Media 6631
DAC chip TI PCM5102A 32-bit chip
Sampling Rate: Up to 32-Bit, 192kHz
Inputs: 1 Asynchronous USB2.0, 1 RCA
Outputs: 1 1/4" and 1 1/8" headphone outputs, 1 RCA (same
connector as the input)
Headphones impedance 8-600 Ohms
RCA input impedance 100 Kilo-Ohms
Max Output: Approx. 1 watt @ 32 ohms
Frequency response: 11Hz to 27kHz, +/-0.5dB
Distortion: <0.03%
S/N: 95dB
Power consumption 25W max
Mains Supply: 100-120V, 220-240V, 50/60Hz, user selectable
Fuse slow blow fuse, 400mA@115V, or 200mA@230V
Amp body and PSU finish Anodized Aluminum
Dimension: AMP: 4.8" L x 4.8" W x 5.1" H with glass
PSU: 7" L x 3.5" W x 2.2" H
Weight: AMP - 5.3 lbs / 2.4kg, Glass - 3.3 lbs / 1.5 kg
PSU - 2.8 lbs / 1.4 kg

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Reviews
The WA7 is one of the few home headphone amps that sounds great with full-size and
in-ear headphones. - Audiophiliac
This is possibly the most linear DAC and headphone amp I've heard.
-Positive Feedback
The Woo reaches DEEP, and is POWERFUL. It’s everything you want it to be and just
a tad more … because it’s so damn sexy you feel like you stole it from the future
somehow. -Humanovation
Appreciable about the WA7 was that whatever headphones or IEMs I used with it, the
performance was consistent. -Currawong @ head-fi.org
the WA7 is practically a steal in terms of sound quality and physical presentation. - HP
Soundings

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Woo Audio is committed to continuously improve its products.
We therefore reserve the right to improve on our design without notice.