Woo Audio WA7d User manual

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WOO AUDIO WA7d Fireflies Duo
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 5
CONNECTION OPTIONS 8
QUICK INSTALLATION 9
OPERATIONS 13
FAQ - FREQUENTLY ASKED QUESTIONS 14
WARRANTY AND SERVICE 15
PRODUCT SPECIFICATION 16

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Overview
Thank you for choosing a Woo Audio product. WA7d “Fireflies Duo” Amp/DAC is a
combination of a high performance vacuum tube headphone amplifier and a USB
Digital-to-Analog Converter (DAC). WA7d is a pure tube design, utilizing a pair of 6C45
tubes in a class-A, single-ended topology with transformer-coupled outputs. There are
no semi-conductors used in the entire signal path. The internal advanced DAC is
capable of processing up to 32 bit/192k sampling rates. The latest asynchronous USB
technology is employed to maintain data transmission purity. WA7d features a pair of
Nickel Alloy core output transformers, multi-layer military grade PCBs and a linear
power supply. To ensure the highest level of performance and noise rejection, we
housed the custom Toroidal power transformer in an external chassis. Despite its
compact size, WA7d Fireflies Duo is a powerhouse and can drive the most demanding
audiophile headphones available. WA7d can also accommodate the most sensetive in-
ear-monitors (IEMs) via an ultra quiet, dedicated 3.5mm output port. With care, WA7d
Fireflies Duo will deliver many years of musical enjoyment. Please take a short time to
read this manual in its entirety to familiarize yourself with the features and connectivity
options of your WA7d.
Features:
oHandmade output transformer with Nickel Alloy core
oUp to 32-Bit, 192kHz high resolution playback
oAsynchronous ultra-low jitter USB 2.0
oSelectable high and low impedance output
oOpen load protection will automatically engage to prevent the amp from damaging when no
headphones are plugged in.
oMulti-functional switch for Optical input, USB input, and RCA input.
oAll-aluminum chassis with no screws visible from any viewing angles
oMulti-layer military grade PCBs
oA thick block of high clarity tube protection glass
oAvailable in anodized Black and Silver color
oCustom driver for Windows Vista/XP/7/8
oUSB Audio Class 2.0 is natively supported by Apple OS X version 10.6.4 and later without drivers

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Getting Started
What’s in the box?
①Umbilical DC Power Cord
②Micro-fiber Polishing Cloth for glass and metal cleaning
③Anti-slip silicone rubber glass pads (4pcs)
④WA7p External Power Supply
(not included when WA7tp tube power supply is purchased)
⑤Tube Protection Glass
⑥WA7d Fireflies Amplifier
⑦6C45 Matched Pair Tubes
⑤
⑥
* USB, AC power cord,
and inter-connection
cables are not included.
①
②
④③
⑦

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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 pay close attention to vacuum
tube installation alignment marks!
⑪USB 2.0 digital input
⑫RCA analog input
⑬Optical digital input
⑭Input-output switch
Optical – optical digital input
RCA –RCA analog input
USB – USB 2.0 digital input
⑮High and low headphone impedance switch
HI-Z – High impedance
LO-Z – Low impedance
⑯Umbilical power cord socket (male)
⑰Power switch
I – ON
O – OFF
11
10
12
16
15
14
13
17

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⑪Umbilical cord socket
(Female)
⑫Power LED light
11
12
13
14
⑪AC power inlet
⑫Fuse box
Slow blow fuse,
400mA@115V or
200mA@230V
External Power Su
pp
l
y
(
WA
7p
solid state
p
ower su
pp
l
y)
Optional WA7tp
V
acuum Tube Power Supply is
available for WA
7
and WA
7
d am
p/
DAC

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Connection Options
AM/FM tuner, XM Sirus satellite radio
Turntable (with Phono stage)
iPod, iPad, MP3 player
PC and Mac
CD player
Super Audio CD player/SACD
Blu-ray player, DVD player
Game consoles
*Compatible, but not limited to.
Appropriate cables and adaptors may
be required.

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Quick Installation
Installing tubes
Umbilical Power Cord Installation
20
A
lign 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 harder
to insert tubes,
never apply
circular motion.
Connecting the Amplifier 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.
Connecting the Power Supply uni
t
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 need to 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.
U.S.
Euro
p
ean
U.K.



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Powering Up
To power up on the WA7d Fireflies, flip the power switch ⑰to the “I”position. The LED on the power
supply will light up ⑫. Vacuum tubes should also light up the same time.
Using the Asynchronous USB 2.0 port:
The WA7d Fireflies Duo offers a USB 2.0 port is compatible with Windows or Macintosh OS computer.
Configuring Mac
Open AudioMidi and right-click on the device listed as “Speaker” in the device section on the
left pane. Ensure that “Use this device for sound output” is selected. “24bit Integer” should be
available in the drop down list on the right side.
Select the appropriate sample rate for
the music file t
yp
e.

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Installing the USB driver (Windows PC only)
*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 USB Speakers 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 may be 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 cell
phones, Wi-Fi routers and radios to avoid noise interference.
oKeep away from water or excessive moisture.
oTurn off the amp if the audio stream or unit sounds 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 removing them.

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FAQ - Frequently Asked Questions
Computer cannot find the WA7d Fireflies Duo USB DAC.
oCheck USB cable connection and make sure the cable meets USB 2.0 specifications.
oSee “Mac OSX 10.9 does not recognize USB device” for Apple Macintosh computers
oSee “Installing USB driver” section for Windows PC
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 (spare fuse included).
Mac OSX 10.9 does not recognize USB device
On some Macs with USB 3.0 running OS X Mavericks 10.9, WA7 and WA7d Fireflies can occasionally lose
connection to the Mac. If this has happened to you, please give the following a try.
- Use a good quality USB cable
- Disconnect all USB devices connected to your Mac
- Remove all audio plug-ins from Mac
- If you have Apple Cinema Display powering your MacBook via Thunderbolt, please disconnect as well.
With the Mac AND WA7d powered ON, disconnect the USB cable. Wait a few seconds.... reinsert the
USB cable. Next, following instruction on “Configuring Mac” section.
Lastly, try a powered USB hub like the Belkin F4U040v


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 [email protected]
Any modification not authorized by WOO AUDIO will void this warranty.

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Product Specification
Model: WA7d Fireflies Duo
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 6631A
DAC chip TI PCM5102A 32-bit chip
Sampling Rate: Up to 32-Bit, 192kHz
Inputs: 1 Optical (Toslink), 1 Asynchronous USB2.0, 1 RCA
Outputs: 1 1/4" and 1 1/8" headphone outputs
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, Amp available in Black and Silver
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
Woo Audio is committed to continuously improve its products.
Features and specifications are subject to change without notice.