Quest Engineering QX-4150 User manual

QX-4150 USER MANUAL | 01QUESTAUDIO.NET QUESTAUDIO.NET
QX-4150
USER MANUAL

QX-4150 USER MANUAL | 02QUESTAUDIO.NET
PRODUCT OVERVIEW
The Quest Engineering QX-4150 is a 4 channel 1RU power amplier suited for any application requiring
superior performance and reliability. Ideal for multiple zone applications providing commercial sound
installations with clean and reliable power. The QX-4150 provides 150 watts per channel of operation into
4 and 8 ohm loads and can bridge channel outputs that can be congured to deliver full channel power
to either low- or high-impedance loads. High and Low pass lters, limiters and standby are available per
channel with fast 1ms wake up time. For high end commercial, AV or domestic applications, the QX range
of ampliers provide superior class D performance with proven reliability without compromise.
SAFETY PRECAUTIONS
•Please read the instructions in this section carefully before use.
•Ensure all instructions in this manual are observed as all information contained within is very important.
•It is also highly recommended that this manual is retained for future reference.
SAFETY SYMBOL & MESSAGE CONVENTIONS
The safety symbols described are used in this manual to prevent bodily injury and property damage which
could result from mishandling. Before operating this product, please read this manual rst, in full so you
that you are thoroughly aware of any risks.
Indicates a potentially hazardous situation which,
if mishandled, could result in serious personal injury or death.

QX-4150 USER MANUAL | 03QUESTAUDIO.NET
•Do not expose the unit to any moisture
whether rain, water, or other liquids. Exposure
to moisture could result in damage to internal
components or electrocution\circuit failure.
•Do not cut, kink, or otherwise damage or
modify speaker cable. Ensure a speaker cable
with a core diameter of at least 0.75mm2is
used for specied performance.
•Do not install or place speaker cables or
this device near heaters, high trac areas
or any area where the cables or device can
be damaged.
•Avoid installing or mounting speaker
boxes, ampliers, electronics or cabling
in unstable locations.
•In the event of storms and/or lightning, ensure
all devices are disconnected from mains power
in order to prevent damage to any of the units
in the system.
•When cleaning the unit, ensure it has been
disconnected from any power source and that
only a dry cloth is used. Do not use any aerosol
or liquid-based cleaners.
•Ensure all electronics are electronically
grounded (earthed) to a safety ground
terminal in order to avoid electric shock.
Do not ground any device to a gas pipe as
this may result in re.
•Servicing of all electronics should only be
carried out by a certied Quest technician.
Please consult your original place of purchase
to nd the location of your nearest Quest
service centre.
•When installing ampliers and/or other
electronics only use the hardware specically
designed for this product.
GENERAL CAUTION

QX-4150 USER MANUAL | 04QUESTAUDIO.NET
FRONT PANEL CONTROLS
CH1
CH2
CH3
CH4
Rotary gain control
A
Blue: Amplier active
Orange: Amplier is in standby mode
POrange: Amplier is in protect mode
SGreen: Signal is detected
L
Orange: Amplier is limiting signal or muted if in standby
mode
Red: Amplier is clipping
HPF
O: Amplier passing full range signal
On: 80Hz High Pass Filter Active (24dB/Oct)
LPF
O: Amplier passing full range signal
On: 100Hz Low Pass Filter Active (24dB/Oct)
LIMIT
O - Amplier will not limit
On - Amplier will limit to prevent clipping
A-STBY
O - Amplier will not enter power saving mode
On - Amplier will enter sleep mode after 25 minutes of
no signal
BRIDGED-MONO
O: Amplier operating as 2 individual channels
On: Amplier operating in bridged mono mode

QX-4150 USER MANUAL | 05QUESTAUDIO.NET
REAR PANEL CONNECTIONS
CH1 Input
CH2 Input
CH3 Input
CH4 Input
Phoenix/Euroblock
CH1 Output
CH2 Output
CH3 Output
CH4 Output
Phoenix/Euroblock
Mains Connection IEC
Blank Plate for Expansion Module (optional)

QX-4150 USER MANUAL | 06QUESTAUDIO.NET
BASIC OPERATION GUIDELINES
Due to the advanced power saving feature of the QX-4150, the amplier has been designed to power
from the mains with no additional switch. The amplier has a removable grille on the front panel. The
grille is held in place magnetically and can easily be removed without tools to access controls to engage
a number of modes which are described in the next section. High Pass and Low Pass lters can also be
activated to provide basic frequency dividing functions, these are most commonly used in a system with
sub-woofers.
To avoid harm to connected speakers it is important to not clip the amplier for extended period of times.
Clipping occurs when the input signal is excessive and overloads the input or output of the amplier.
To avoid clipping reduce the level of the input. The amplier has a selectable limit option which can be
engaged to help avoid clipping and it is recommended that this mode is used if the potential exists for
extended periods of overdriving.
The amplier has a protection circuit which activates when a fault condition exists. The LED will stay
illuminated until the fault is resolved. The protection circuit activates to help prevent damage to the
amplier and connected speakers. Common causes can be shorted wiring or faulty speakers. If the
Protect light illuminates disconnect the amp from power and then disconnect the speakers. Reconnect
the amp to mains and check the status of the protect LED, if the LED has not turned back on then check
the speakers and cabling for faults.
If the amplier is to drive high impedance speaker loads (70 or 100v) then Bridge mode must be enabled,
it is possible to have half the QX-4150 running high impedance loads and the other half running low
impedance loads, e.g. Ch 1&2 Bridged 70/100v and Ch 3&4 connected to separate 4/8 ohm loads or
bridged to 4/8 ohm or 70/100v.

QX-4150 USER MANUAL | 07QUESTAUDIO.NET
OPERATION MODES
Active Mode is indicated by a Blue LED, the amplier is connected to power and ready to pass signal.
The Orange LED indicates the amplier is in Standby, a power saving mode. This mode can be enabled by toggling the under
panel A-STBY switch from O to On. In this mode if no signal is detected for 25 mins the amplier will “sleep” and wake within
660ms of detection of signal.
Mute mode puts the amp into a “light sleep” and occurs when the Standby option has been selected and no signal has been
detected for 10mins, if the amplier detects signal it will wake within 1ms. When no signal has been detected for 25 mins full
sleep mode will activate.

QX-4150 USER MANUAL | 08QUESTAUDIO.NET
QX-4150
QX-4150
QX-4150
QX-4150
INPUT/OUTPUT WIRING
Balanced Input Wiring Unbalanced Input Wiring
Output Wiring Bridged-Mono Balanced Wiring
If the amplier is to be used in Bridge Mono mode for low impedance speakers or to drive high impedance
loads (70-100v), the under panel Bridged Mono control switch should be in the On position and input
connection wired to input 1 for channels 1&2 and channel 3 for channels 3&4. This can easily be remembered
by noting the circle around the + and – signals on input connectors 1&3.

QX-4150 USER MANUAL | 09QUESTAUDIO.NET
SPECIFICATIONS
MODEL PER CHANNEL BRIDGED-MONO MODE
LOAD 8Ohm 4Ohm 70V
(22Ohm)
100V
(33Ohm) 8Ohm 4Ohm 70V 100V
Maximum Dynamic Power
(@1KHz, 1% THD) 4x 200W 4x 275W NA NA 2x 550W 2x 550W 2x 550W 2x 550W
Maximum Continuous Power
(@1kHz, 1% THD) 4x 150W 4x 150W NA NA 2x 280W 2x 260W 2x 250W 2x 240W
Features
Wake On Music, Auto-Mute
(1ms wake-up), Limiting on
High Temperature
Amplier Protection Systems
Thermal protection,
Over-Current Protection,
DC Protection, HF Protection
Mains Input Voltage Range 85VAC - 265VAC
Standby Power Consumption 3.8W
Muted Power Consumption 9.5W
Idle Power Consumption 16W
Standard Power Consumption
(Pink Noise@ 1/8th Rated
Power, 8Ohm)
75W
Output Connector 2-pin Phoenix (5.08mm pitch)
with a screw lock
Mains Connector Standard IEC C14
Dimensions (H x W x D) 44 x 482 x 344 mm
(1.75 x 19 x 13.5")
Weight 5.3kg (11.7 lbs)
Accessories Mains Cable, Feet, User Manual,
Phoenix Plugs
Frequency Response 20-20kHz (+/-0.3dB)
Peak Output Current 25A
Dynamic Range 104dB (A-weighted)
Noise Level -72dBu (A-weighted)
Distortion (1kHz@1W/8Ohm) 0.006%
Distortion (1kHz@50W/8Ohm) 0.006%
Crosstalk (1kHz@1W/8Ohm) -90dB
Gain 26dB/32dB
Maximum Input Level +24dBu
Input Type
Analogue Balanced 3-pin
Phoenix (5.08mm pitch) +
Optional Expansion Module
Input Sensitivity +7dBu/+4dBu
Input Impedance 10kOhm
Output Resistance 22.5mOhm/43.6mOhm
Front Controls
Volume Adjust, 80Hz HPF
Enable, 100Hz LPF Enable,
Bridged-Mono Enable, Limiter
Enable, Auto-Standby Enable
Indicators (LEDs)
Blue/Orange Active/
Standby
Orange Protection
Green Signal
Detection
Orange/Red Limiter/Clip
Cooling Fan cooled, temperature
dependent
* All specications were measured at 240VAC
** Quest Engineering reserves the right to make changes in
specications, or products without prior notice.
*** The gures shown above are ‘real world’, usable specications and
are conservative as a result. Quest Engineering does not believe in
portraying misleading or exaggerated specications.

QX-4150 USER MANUAL | 10QUESTAUDIO.NET
TECHNICAL DRAWINGS
QX-4150
345mm
Height
1RU
19"

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