QHW Audio THE BOX II User manual

THE BOX II
Owner's manual

THE BOX II
Owner's manual
2
Index
This manual has the following sections:
 Safety warnings
 Welcome
 Rear panel description
 Installation and connections
 Setting gain
 Operation
 Troubleshooting

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Owner's manual
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Safety warnings
NEVER OPEN THE EQUIPMENT: There is a risk of
electric shock inside. Only qualified personnel
should open the device. There are not user
serviceable parts inside.
DO NOT EXPOSE THE EQUIPMENT TO MOISTURE
OR WATER: Exposing the equipment to moisture
or water can lead to a risk of electric shock or fire.
If, due to any circumstance, the device gets wet in
such way that water could reach the interior, take
it to a technician before connecting it again in
order to verify it didn't suffered damage which can
lead to danger.
DO NOT USE THE EQUIPMENT NEAR WATER: This
equipment must not be used near water,
bathtubs, wash tubs, swimming pools or any other
you can imagine. If the equipment gets wet or
water it should lead to a risk of electric shock
and/or fire, and get permanently damaged.
DO NOT PLACE THE EQUIPMENT NEAR HEAT
SOURCES: Keep a reasonable distance between
the equipment and heat sources for it not getting
direct heat from heaters, candles, fireplaces, air
conditioners or any other appliances which can
send out heat, as computers or power amplifiers.

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Owner's manual
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Do not place the equipment blocking ventilation
outlets from other equipment.
CLEANING: Disconnect the appliance from mains
before cleaning it. Use a clean and dry cloth. Do
not use aggressive cleaning chemicals, as glass
cleaners, because it could damage painting.
This apparatus meets the requirements found in
European Council directives 2006/95/EC,
2004/108/EC, 2009/125/EC y 2002/95/EC.

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Owner's manual
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Thank you
Thank you very much for purchasing a
QHW Audio product designed by sound lovers for
sound lovers and congratulations for your
intelligent decision. This is an electronic
instrument designed for accomplish its task with
great precision and fidelity for many years. This
manual will help you in your new equipment
installation and will give you information about its
working. Please, read it before using it.

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Owner's manual
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Rear panel description
1. DC power input.
2. Audio RCA inputs.
3. Audio RCA outputs.

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Owner's manual
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Installation and connections
For installing The Box II in your audio
equipment you will need two stereo audio wires
(or four, if you want to use wires which doesn't
come by pairs) with RCA connectors.
Before making any connection,
make sure that The Box II is
unplugged from mains and any
other equipment taking part in
connection is powered off.
Connect outputs form equipment sourcing
signal to The Box II input to the input terminals
[number 2 in description drawing] in the device
rear panel and paying attention to channels LEFT
and RIGHT order.
Connect outputs from The Box II [number 3
in description drawing] in device rear panel, to the
inputs of the equipment which The Box is sending

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Owner's manual
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its signal to, paying attention to channels LEFT and
RIGHT order.
Following drawings show a generic
connection schema and some examples for setting
up The Box II in your system:

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Owner's manual
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Owner's manual
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Owner's manual
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Owner's manual
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The Box II comes with an external DC
power supply with can handle an input from 100 V
to 240 V AC from 50 to 60 HZ and gives an output
of 36 V of DC with a maximum of 1 A of current.
QHW Audio only warranties its specifications when
you are using the supplied power supply. The DC
input is connected internally in the way that
positive goes to center pin and negative to sleeve.
Once all audio wires are connected,
connect the DC power supply, putting firmly the
connector in the rear panel DC input connector of
The Box II [number 1 in description drawing].
Make sure that mains cable of
DC power supply is disconnected
from mains outlet before
connecting DC power supply to
The Box II.
Now connect the mains cable to the mains
outlet using an outlet that provides a safety earth
connection.

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Owner's manual
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The power supply supplied by
QHW Audio uses safety earth
and must be connected to an
outlet which provides it.
If cable included with The Box II does not fit your
region plug, you will need one complying with
IEC60320 C14 in The Box II external power supply
end.
Setting gain
The Box II features a configurable by user
gain. This gain can be set to 0.8, 3, 6, 9.5 or 12 dB
to suit your needs and tastes. Configuration is
done by setting the microswitches accessible from
the bottom of unit. Each switch has two positions,
OFF and ON. To change each switch you can gently
use a little screwdriver or your finger tip. Pay
attention that configuration is the same in both
channels.

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Owner's manual
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Gain goes as described in table:
SW1 SW2 SW3 GAIN
OFF OFF OFF 0.8 dB
ON OFF OFF 3 dB
OFF ON OFF 6 dB
OFF OFF ON 9.5 dB
OFF ON ON 12 dB
Rest of positions are not officially
supported, nevertheless The Box II will sound and
work without any problem with values of gain
between or above the listed ones.

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Owner's manual
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You can set gain with The Box II powered
on or off. If volume is too high or The Box II is
connected to a very sensitive power amplifier,
small noises can be heard when switching gain at
no signal and if there is a signal present while
doing it, take in consideration increasing gain will
result in louder sound at your speakers. Therefore,
be careful with results.
Operation
During operation, LED light in frontal panel
will be on. This light is not direct and comes from
interior of enclosure, so depending on angle you
are viewing it from you will see it brighter or
dimmer. This has been made this way to avoid LED
to disturb you when in darkness in your Home
Theatre watching a movie, in example.
When The Box II powers up you can hear a
small noise, especially if it is connected to a very
sensitive power amplifier. This is normal behavior,
The Box II does not have mutting relays or

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Owner's manual
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transistors at its outputs because a precise DC
servo keeps starting up “thumps” under control.
It is not needed you power off The Box, its
consumption is low, lower than 9 watts and is
protected against overcurrent and overvoltage
from mains. Keeping it always on or to power it on
and off each time you use your system is your own
decision.
As any electronic appliance, it is
recommended to unplug it if you are going to
spend a long time out from your home, like, for
example, for holidays or if there is an electrical
storm.

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Owner's manual
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Troubleshooting
Frontal LED does not light.
 Check DC power cable is firmly set.
 Check mains cable of external DC power
supply is firmly set into supply.
 Check, plugging another device, that the
mains outlet has current.
Sound is distorted, especially when the level
rises.
 Check all audio cables are firmly put in their
terminals.
 Try another cable, it may be some damage
not visible in an apparently right cable,
create distortion and strange noises.
 Lower the input level (source level) to The
Box II because it, due to gain, it was doing
and excess of signal level (clipping) in the
device connected to its output.
 Try to connect your system without The
Box II for discarding trouble source is in
another equipment.

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Owner's manual
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A loud or annoying hum is heard.
 Check all audio cables are firmly put in their
terminals.
 Try another cable, it may be some damage
not visible in an apparently right cable,
create distortion and strange noises.
 If possible, try to use another mains outlet
to see if noise disappears.
 Unplug and disconnect from audio chain all
equipment except those essential to see if
noise source is a device not working in that
moment.
 Try to connect your system without The
Box II for discarding trouble source is in
another equipment.
Never disconnect earth
connection from supplied power
supply as solution for hum. That
can be a safety risk for persons.

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Owner's manual
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Technical specifications
Input impedance: 50 KOhm
Output impedance: 10 Ohm
Maximum output level: 9.5 V RMS
Residual noise: < 1 uV RMS (input terminated with
47 Ohm)
Signal to noise ratio (referred to 1 V RMS): 126
dB or better
EIN: < -123 dBu (input terminated with 47 Ohm, +6
dB gain)
Total Harmonic Distortion at 1 KHz, 20 Hz – 20
KHz passband: < 0.0006 % (at any gain, up to 4 V
RMS of output on 10 KOhm load)
Intermodulation Distortion (19 KHz, 20 KHz): <
0.0006 % (at any gain, up to 4 V RMS of output on
10 KOhm load)
Frequency response: 20 Hz – 20 KHz better than
±0.1 dB
Power supply: output 36 V DC 1A, input 100 – 240
V AC 50 – 60 Hz
Dimensions (L x W x H): 155 x 109 x 45 mm

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Owner's manual
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QUALITY HI-FI WORKS AUDIO, S. L.
THE BOX II OWNER’S MANUAL. VERSION 1.0.
ENGLISH.
Madrid, 15 de marzo de 2021.
MADE IN SPAIN.
© 2021 Quality Hi-Fi Works Audio, S. L. Puerto
Serrano, 12. 28045 Madrid. Tel: [phone]
email: [e-mail]
THE BOX II - Owner's manual - ver. 1.0.1 EN – 290521 -
Specifications subject to change without prior notice.