Alto Professional APX1000

1000W 2-Channel Class D Digital Power Amplifier


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Product Features

  • 2-Channel Class D Digital Power Amplifier
  • RMS Power Rating:
    • 8 ohms: 250 watts x 2 chan.
    • 4 ohms: 500 watts x 2 chan.
    • Bridged, 8 ohms: 1000 watts x 1 chan.
  • High-Efficiency low-noise switch-mode power supply
  • Lightweight, two rack-space design for easy integration into your existing equipment
  • Easy to read LED signal (green), protection (red) and clip (red) indicators
  • 1 Blue LED power indicator integrated with power switch
  • Touch-Proof binding posts and Speak-On jacks
  • Low-Noise cooling fan to prevent overheating and high-current toroidal transformers
  • Balanced combo input jacks
  • 4-Way System Protection circuitry (On/Off, Mute, DC Fault, Load)
  • Input Sensitivity: 1 Volt
  • High-Pass filter (30 Hz)
  • Low-Pass filter
  • Input Impedance: 10k ohm unbalanced
  • Voltage Gain: 32 dB
  • THD (Total Harmonic Distortion): <0.5%
  • Signal-to-Noise Ratio: 110 dB
  • Frequency Response: 20-25,000 Hz
  • Dimensions: 11-1/4"D x 19"W x 3-1/2"H
  • Also Found as: apx1000 APX-1000
  • 1-year Manufacturer's warranty

Power Specifications

Number of Channels
This is the number of channels that the professional amplifier is designed to power.
2 Channels
Continuous Power @ 8 ohm
This is the continuous (RMS) power output of the amplifier at an 8 ohm impedance.
250 watts x 2 channels
Continuous Power @ 4 ohm
This is the continuous (RMS) power output of the amplifier at an 4 ohm impedance.
500 watts x 2 channels
Continuous Power @ 8 ohm (Bridged)
This is the continuous (RMS) power output of the amplifier at a bridged 8 ohm impedance.
1000 watts x 1 channels
Total Continuous Power
This is the total continuous power rating (RMS) that the amplifier is able to output.
1000 watts

Amplifier Specifications

Amplifier Class

An amplifier increases the power of the signal being fed to it by taking energy from its power supply and matching the signal but increasing its amplitude. Amplifiers use many different methods for converting these electrical signals and have been categorized into classes.

Class A/B: Greater than 50% of the input signal is amplified while the other percentage is “off”. These amplifiers have a small amount of current flowing through the output transistors all the time which almost eliminates crossover distortion. Class A/B has great sound quality but is not as efficient as class D. These amps are most commonly used to drive speakers.

Class D: Also known as switching amplifiers, class D amps have output transistors that are completely turned “on” or “off”. This means that when the transistors are on, there is almost no voltage across them but when they are off there is significant voltage but no current flowing through it which makes these amplifiers very efficient at the cost of sound quality. These amps are most commonly used to drive subwoofers.

Other Classes: You may see classes such as GH, bD, X, FD, etc. by some manufactures. These amplifiers tend to be either class A/B, D or a hybrid of the two but with improvements to their designs that can make them more efficient or offer better sound quality.

Signal-to-Noise Ratio
This spec compares the strength of the signal to the level of background noise. A higher value indicates less background noise.
110 dB
Frequency Response
The range of frequencies the amplifier will reproduce (lowest frequency to the highest). Bigger is better, meaning the wider the range, the better. The optimal range is 20 - 20,000 Hz (which is the range of human hearing).
20 - 25,000 Hz
Input Sensitivity
This is the input sensitivity of the amplifier.
1 volts
THD (Total Harmonic Distortion)
The amount of change in harmonic content of the signal as it is amplified. A lower figure indicates less change and a more accurate amp. THD below 0.10% is inaudible.
Voltage Gain
This is the voltage gain of the amplifier measured in decibels.
32 dB
Cooling Options
These are the different cooling systems used in the amplifier to keep it cool.
Cooling Fan
These are the type of input connections that the amplifier has.
These are the types of output connections that the amplifier has.
Binding Posts

Physical Specifications

The height of the item, measured from top to bottom, in inches.
The width of the item from left to right (side-to-side) measured in inches.
The front-to-rear depth of the item, in inches. If the item is angled or slanted, this value is the bottom measurement.
Weight (Pounds)
This is the weight of the item in pounds (lbs).
12.1 lbs
Rackmount Spaces
This is the total number of spaces that the preamplifier will occupy when mounted on a rack.

Specials with this Item

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Warranty and Return Policy

Parts Warranty Duration
1 year
Labor Warranty Duration
1 year
Warranty Provider

Summary of Customer Ratings & Reviews

Rating Distribution

5 Star
4 Star
3 Star
2 Star
1 Star

Average Attribution Rating


Mount Morris, Illinois

Alto Professional APX1000

June 2, 2013

I boought this power amp to replace my very old Peavey CS 800, a channel went out plus other problems. The Alto is Class D which is light and easy to use. I have band rehearsals here every week and it is necessary. The sound is clean and clear at any volume and it never gets hot. Very quiet running. If I were to buy again I would opt for more wattage. I only use mic'ed vocals through the amp via an Alesis (Alto) 16 channel mixer which is on par with a Mackie VLZ. I have the amp volume maxed at all times and it has never reached clipping. I have never had any problems with Alto products.

5 of 7 found this helpful

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Sonic Electronix Wiring Guide

Wiring Diagram Legend

Warning: The image depicted shows the resistance change when wiring multiple subwoofer terminals. Please refer to your subwoofer's owner's manual for the proper wiring of its terminals. Sonic Electronix, Inc. is not responsible for damage caused to your audio system or vehicle due to improper installation. Please call tech support at 1-877-289-7664 if you require additional assistance.

Product Name: Alto Professional APX1000

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Alto Professional APX1000

1000W 2-Channel Class D Digital Power Amplifier


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