Alto Professional APX2000 User manual

APX2000
QUICKSTART GUIDE
ENGLISH ( 2 – 6 )
GUÍA DE INICIO RÁPIDO
ESPAÑOL ( 7 – 11 )
GUIDE D'UTILISATION SIMPLIFIÉ
FRANÇAIS ( 12 – 16 )
GUIDA RAPIDA
ITALIANO ( 17 - 21 )
KURZANLEITUNG
DEUTSCH ( 22 – 26 )
SNELSTARTGIDS
NEDERLANDS ( 27 – 31 )

2
QUICKSTART GUIDE (ENGLISH)
BOX CONTENTS
APX2000
Power cable
Quickstart Guide
Safety & Warranty Information Booklet
QUICK SETUP
1. Make sure all items listed in the BOX CONTENTS section are included in the box.
2. READ SAFETY & WARRANTY INFORMATION BOOKLET BEFORE USING THE PRODUCT.
3. Study the connection diagram in this guide.
4. Place all devices in an appropriate position for operation.
5. Make sure all devices are turned off and all faders and gain knobs are set to "zero."
6. Connect all sound sources' outputs to amplifier inputs as indicated in the diagram.
7. Connect the amplifier outputs to speakers.
8. Plug all devices into an appropriate power source.
9. Switch everything on in the following order:
•Sound sources (i.e. microphones, turntables, CD players, etc.)
•Mixer
•Amplifier
•Speakers
10. When turning powering down, turn everything off in the following order:
•Speakers
•Amplifier
•Mixer
•Sound sources
CONNECTION DIAGRAM
Do NOT make any connections
when any device is powered on.
Note: Please see the SPEAKER
CONNECTION section for important
setu
p
information.
STEREO
+
-
CH3
CH3
CH4
CH4
CH4
CH4
CH3
CH3
CH1
CH1
CH2
CH2
CH2
CH2
CH1
CH1
+
-
AMPLIFIER
MIXER
SPEAKERS
POWER

3
WARNING!: Do not adjust the
STEREO/MONO BRIDGE SWITCH when the
amplifier is on.
How do I know if my 1/4" cables
are balanced?
BALANCED
UNBALANCED
REAR PANEL DIAGRAM
CH3
CH3
CH4
CH4
CH4
CH4
CH3
CH3
CH1
CH1
CH2
CH2
CH2
CH2
CH1
CH1
33
33
4
42
2
1
5
555
55556
1. COOLING FAN- This fan secures cooling for the amplifier. The airflow is from front to rear. The fan speed is
electronically regulated depending on the temperature of the power devices. Do not block these fan grills or
mount the amplifier in an enclosed rack, which could cause the amplifier to overheat.
2. LOW PASS FILTER – This switch activates the built-in low cut filter. All audio below 30 Hz will be removed
from the output signal.
3. BALANCED COMBO INPUTS – Connect your mixer to the balanced XLR
or balanced 1/4" input for that channel.
4. OUTPUT MODE SWITCH – The APX2000 presents three operating
modes:
Stereo Mode
In this mode, CH 1 and CH 2 operate independently (as a normal stereo amplifier) The CH 1 input signal will
be output from the CH A output connector, and CH 2 input signal will be output from the CH 2 output
connector.
Parallel Mono Mode
In this mode, CH 1 input signal will be output from the
output connectors of both channels.
Bridged Mode
In this mode, CH 1 input signal will be output from the
bridge-mono output connector.
5. CHANNEL OUTPUTS – Connect your speakers' input
jacks to these outputs.
•For the binding posts, red is the positive signal and
black is the negative signal. Please make sure to
respect the speaker polarity when using binding
post. Turn off the unit before connecting an audio
signal to the binding post to avoid any electric shock!
•The SPEAKON* outputs are specifically designed to connect to high power speakers. The correct
polarity is secured automatically. They prevent shock hazard and they lock-in securely.
6. POWER IN – Connect the cable to a standard wall outlet. Be sure the supplied voltage matches the required
voltage of the amplifier. Do not connect the amplifier to an outlet that does not match the required voltage;
doing so could damage the amplifier.
* Speakon is a trademark of Neutrik® AG, registered in the U.S. and other countries.
WARNING!: Do not allow any wires of
adjacent terminals to come in contact with each
other. Also, do not connect either positive
(red) output to chassis ground.

4
FRONT PANEL DIAGRAM
CH3 CH4
1
2
4
35
66 6 6
7
7
7
7
1. POWER SWITCH – Turns the amplifier on/off.
2. POWER LED – Illuminates when the amplifier is on.
3. LED METERS – Indicates the audio signal level. This LED will light up when the signal at the output is at least -
20 dB.
4. CLIP – The red "Clip" light indicates the signal is distorting or "clipping," which occurs when the volume
exceeds the amplifier's maximum output. This LED will flash when distortion reaches a level of 0.5%.
Consistent clipping can damage your amplifier and speakers. If the signal is regularly clipping, reduce the
volume of the amplifier. If it is lit about half the time, the amplifier channel's thermal protection will cause the
channel to shut down within a few minutes.
5. PROT – The red "Prot" light indicates the output for that channel has turned off to protect your amplifier and
speakers, which can be damaged by excessive volume resulting in clipping. If the meters' red lights are
illuminating, decrease the levels of your CHANNEL GAIN knobs.
6. CHANNEL GAIN – This knob controls the channel's output signal.
7. COOLING VENTS – These vents help to cool the internal parts of the amplifier when in use. Do not block
these vents, and keep the vents clean at all times.
SPEAKER CONNECTION
SHORT CIRCUIT PROTECTION
Output short circuit protection protects the output devices of the amplifier from short circuits and stressful loads. If
your speaker lines short, the amplifier automatically detects this problem and discontinues operation for that channel.
(If one channel's short circuit protection is activated, the other channel will continue to operate normally.) During short
circuit protection, the "Clip" and "Protect" LEDs will light simultaneously, and all output from that channel will stop.
Short Circuit Protection can often be traced back to the signal output line (i.e., the speaker line). Check the line from
the output terminal of the amplifier to the speaker. If this line is still good, check the internal speaker connections and
components. (A short circuit can often be traced to a bad cable or a bad speaker component and is rarely traced to
the amplifier itself.)
Bare Wire Connections:
When connecting your speakers to the amplifier using bare wires, follow these
steps:
1. Unscrew the red and black caps of the binding posts. (Be sure not to
completely remove or unscrew the red and black caps.)
2. Strip back the wire insulation 1/2" (13mm).
3. Insert the bare wire into the hole exposed under the binding post cap.
4. After inserting the wire, screw the binding post cap down on the wire.
Spade Connector:
When connecting your speakers to the amplifier using spade connectors, follow these steps:
1. Unscrew the red and black caps of the binding posts. (Be sure not to completely remove or
unscrew the red and black caps.)
2. Insert the spade connectors into the binding posts.
3. Tighten the caps down on the spade connectors.
Banana Connectors:
When connecting your speakers to the amplifier using banana connectors, follow these steps:
1. Be sure that the red and black caps of the binding posts are tightened completely.
2. Insert the banana connectors into the caps of the binding posts. Be sure that the connectors are inserted
securely.
WARNING!:
•Do not make any connections when any device is powered on.
•Do not allow the wires from terminals to come in contact with each other.
•Do not connect either
p
ositive
(
red
)
out
p
ut to chassis
g
round.

5
OPERATION IN STEREO MODE
The APX2000 provides three operating modes: stereo mode, parallel (mono) mode and bridged mode, you can
decide each specific operating mode according to your actual application circumstance.
STEREO
+
-
BREAKER
BREAKER
AC INPUT
AC INPUT
CH3
CH3
CH4
CH4
CH4
CH4
CH3
CH3
CH1
CH1
CH2
CH2
CH2
CH2
CH1
CH1
+
-
CHANNEL 1 CHANNEL 2
In STEREO MODE, channel 1 and channel 2 operate independently (as a conventional stereo amplifier). The channel
1 input signal will be output from the channel 1 output connectors, and the channel 2 input signal will be output from
the channel 2 output connectors.
OPERATION IN PARALLEL MODE
In this mode, the channel 1 input signal will be outputted from the output connectors of both channels. The channel 2
input jack is not used and the channel 1 and 2 volumes can be adjusted independently. Use Parallel Mode when you
want to drive two speakers with only one input signal keeping separate control of the volume of the two channels.
NOTE: Since you are not using the channel 2 input you can use this socket to "daisy-chain" to another amplifier.
PARALLEL
+
-
+
-
BREAKER
BREAKER
AC INPUT
AC INPUT
CH3
CH3
CH4
CH4
CH4
CH4
CH3
CH3
CH1
CH1
CH2
CH2
CH2
CH2
CH1
CH1
+
-
+
-
CHANNEL 3 CHANNEL 4
CHANNEL 1 CHANNEL 2

6
OPERATION IN BRIDGED MODE
In this mode, the channel 1 input signal will be output from the bridge output connectors. (The 2 binding posts) In this
case, use the channel 1 volume control to adjust the volume, keep the volume control of channel 2 turned
completely down (counter clockwise). Bridged mode is intended for driving loads with a total impedance of 8 ohms or
greater.
In Bridge Mode you will combine the power of both channels into one speaker. You will have a large amount of power
available so carefully check the power handling of your speaker before operation.
BRIDGED
+
-
+
-
BREAKER
BREAKER
AC INPUT
AC INPUT
CH3
CH3
CH4
CH4
CH4
CH4
CH3
CH3
CH1
CH1
CH2
CH2
CH2
CH2
CH1
CH1
RACKMOUNTING TIPS
•It is a good idea to mount this in the bottom of a rack frame. Supporting the back of the unit may be
necessary for portable or road use. The APX2000 mounts into a standard 19u rackmount.
•ALTO amplifiers are well shielded; however, mounting low-level electronics some distance away from power
amplifiers is common practice to reduce the possibility of electromagnetic interference into the low level
units, which may sometimes be unusually susceptible to picking up such interference.
•When wiring a rack, it is good installation practice to route all AC wiring along one side of the rack and all
audio wiring along the other side to avoid coupling AC-borne interference into the audio.

32
SPECIFICATIONS
POWER SPECIFICATIONS
•Continuous Power: 4 x 400 W at 4 ohms, 4 x 250 W at 8 ohms (0.5% THD);
2 x 2000 W at 8 0hms (Bridged mono mode)
ELECTRICAL SPECIFICATION
•Input Sensitivity: 1.0 V
•Input Impedance: 10 K Unbalanced
•Frequency Response: (at 10 dB below rated output power) 20 Hz - 25 kHz
(+0/-3 dB)
•Voltage Gain: 32 dB
•Distortion: (SMPTE-1M) <0.5%
•S/N Ratio: 110 dB
•Inrush Current at initial switch on: 23.68A
•Inrush Current after power supply interruption: 13.85A
GENERAL SPECIFICATIONS
•Protection: On/Off, mute, DC-fault, load
•Controls Front: Front Controls: AC power switch, 2 channel level control; –∞
to +30 dB
•Controls Rear: 30 Hz high-pass filter on/off, bridge/stereo/parallel mode
•Signal Indicators: Signal present (green LED), clip (red LED), protection (red
LED)
•Power Indicators: 1 blue LED integrated with power switch
•Input Connectors: Balanced XLR-F / ¼” combo
•Output: Touch proof binding posts and Speakon® NL4 connectors
•Power Supply: AC Power: 100 VAC, or 110 – 120 VAC or 220 - 240 VAC (50
/ 60 Hz)
DIMENSIONS
•(WxLxH): 19in x 14.8in x 3.5in (483mm x 376mm x 88.8mm)
•Weight: 17.6 lb (7.9kg)
MANUAL VERSION 1.1