Whirlwind Qbox Manual

Q Mic/Line Tester
Ses
The Qbox is a multipurpose testing device used for
checking audio lines. The Qbox can send or receive audio
signals at either mic or line levels, as well as detecting
the presence of phantom or intercom voltage on the
whirlwind
THEORY OF OPERATION
The Whirlwind Qbox is a dual function testing device
that combines an audio signal source with a monitor
amplifier. Connections to both sections of the Qbox are
made through a set of male and female XLR jacks which
are parallel wired and electronically balanced. A TT
jack is wired in parallel with the female XLR. Pin 2 is tip
and pin 3 is ring. An XLR split switch will break the
parallel connection providing independent source and
speaker sections. A separate Tip/Sleeve jack is also
included with a DC blocking cap, wired to pin 2 and pin
1 of the XLRs. This jack typically is for passively
monitoring line level with TV IFB type high impedance
mono earpieces (2 K ohms).
The source section of the Qbox provides two options for
sending a test signal down an audio line; tone or mic.
One three position switch selects the balanced output
of either a 440Hz sine wave oscillator or an internal
electret condenser mic and also turns on the power to
the unit. A second three position switch sets the output
level at full +4dBm balanced or attenuated to -20dBm
or -50dBm.
The internal mic is an omnidirectional electret
condenser mic and can pick up most sounds within 10
feet of the Qbox. It is not necessary to talk directly into
the INT MIC hole. Electret mics can easily be damaged
by water, therefore if using the Qbox in rainy
conditions, cover the INT MIC hole with tape. Should
the element need to be replaced, it is available from
Whirlwind.
The speaker section of the Qbox allows the user to
listen to audio signals through either the internal
speaker or stereo headphones. The input is balanced
and will accept mic or line level signals up to +14dBm. A
three position monitor switch allows the selection of
the balanced input or unbalanced pin 2 or pin 3 to be
monitored through the speaker section.
Due to an input impedance of 40K Ohms, looping
through the Qbox will not affect audio quality. The
speaker volume control turns on the power and acts like
an attenuator. The amplifier circuit provides up to 60dB
of gain and only draws significant power when audio is
present. Using the speaker at full volume continuously
will draw 100mA DC from the battery and wear it down
quickly (1/2 hour). When troubleshooting, turning the
volume up with no audio present will not wear down the
battery. The speaker used in the Qbox is a 2.25" 8 Ohm
1/2 Watt type with a paper cone which can be damaged
in severely wet conditions. A replacement is available
from Whirlwind. The 3.5mm TRS headphone monitor
jack turns off the speaker when utilized. The headphone
driver is mono and drives both earpieces on headphones
with 8 to 600 Ohm impedances. To use mono Tip/Sleeve
earpieces with this jack, an internal jumper must be
changed, which disconnects the ring to prevent shorting
of the driver. The small black header jumper is located
on the front corner of the circuit board and is easily
accessible by removing the back of the enclosure (see
diagram).
The Qbox also featues green and yellow LEDs which
detect the presence of positive DC voltages from 9 to 48
Volts relative to pin 1 of the XLR jacks. The green LED
monitors pin 2 and the yellow LED monitors pin 3. Ared
power LED illuminates when either the source or speaker
section is turned on.
Since the Qbox has both a mic and a speaker, it is possible
to turn both of them on and get feedback. The Qbox was
configured this way so 2 units can be used as a 2 way
intercom. Headphones must be plugged into the
headphone jack so that the internal speakers are off.
A 9V 100mA battery eliminator with battery clip
connector can be used to power the Qbox. Do not use a
power source greater than 9 Volts, as it will damage the
speaker driver circuit.
FACE
INT MIC ` TT O
(E)sourCE SPEAKER
VOL
OLTAGE STEREO 4 й
-20dB TONE VOLUME
OFF OpPIN 2
-50dB INT ON
MIC O
OFF
1 23 4 5
1. ATTENUATOR SWITCH selects output level at the XLRs and
unbalanced 1/4 inch JACK.
2. TONE/INTERNAL MIC SWITCH turns the unit on and selects
source sent to XLRs and unbalanced 1/4" JACK.
3. PIN 2 and PIN 3 LEDs sense phantom or intercom power
presence. ON LED indicates either source or speaker side is
turned on.
4. VOLUME CONTROL turns the unit on and adjusts the signal
level to either the headphones or the speaker.
5. STEREO PHONES JACK allows the use of stereo or mono
headphones and disconnects the speaker.
6. TT JACK wired in parallel with the female XLR. When the XLR
split switch is in the connected position, the TT jack will accept
input signal to the Qbox, or will output the mic or tone.
7. XLR JACKS are parallel wired and located on the front of the
unit with 1/4" Tip Sleeve JACK wired to PIN2 and PIN 1.
8. XLR SPLIT SWITCH breaks the XLR parallel connection
providing independent input and output sections.
9. MONITOR SELECT SWITCH chooses the signal sent to the input
of the speaker section.
CHANGING THE JUMPER FOR
MONO EARPIECE USE
To change the JUMPER you will first need to remove the four
screws and the rear panel. The JUMPER is located in the front
left corner near the face plate. Lift straight up on it to change
positions, taking care not to bend the pins. When reassembling,
make sure that the speaker lies flat beside the two built in
STANDOFFS on the rear panel to prevent puncturing of the
speaker cone. Also, speaker CONTACTS need to be resting on top
of the INSULATING FOAM covering the back of the circuit board.
CONTACTS
STANDOFFS
JUMPER
OFF + RING
MONO a
OFF — €
—
RING
ON 7 J
ON + RING
HEADPHONES
INSULATING FOAM
SPECIFICATIONS
40K Ohms balanced
+14dBm balanced
100 Ohms balanced
+14dBm balanced
Input Impedance
Maximum Input Level
Output Impedance
Maximum Output Level
Pad Range -50 and -20 dBm
Range of Speaker
Volüme Control 60dBm
Headphone
8 to 600 Ohms
9V alkaline battery
(Duracell MN 1604
or equivalent)
requirements
Power requirements
REPLACEMENT PARTS
ITEM PART NUMBER
Electret Mic Element MICQ
Speaker SPKRQ
Battery Door BBQDOOR
WARRANTY
This product is guaranteed for one year from the date of
purchase against manufacturing defects. For warranty service,
return the unit, along with the original sales receipt, to:
whirlwind, 99 Ling Road, Rochester, NY 14612, postage prepaid.
We will repair or replace the unit at our option and pay the
return postage.
Specifications subject to change without notice
whirlwind
99 Ling Road
Rochester, NY 14612
585-663-8820
whirlwindusa.com