Class D Amplifiers

ICEpower // Products // Class D Amplifiers

The AS Series

The AS Series consist of intelligent audio amplifier power solutions designed for highly competitive consumer and professional audio applications. The key distinguishing qualities of the modules in the AS Series are excellent audio performance, reliability, application convenience, flexibility, and a wide array of features.

The ASX Series

Take audio reproduction to the next level with the ICEpower ASX Series. These ultra-compact, lightweight class D audio amplifiers with integrated power supplies are designed as highly competitive modules in terms of low cost and carefully chosen features. The four modules in the ASX Series can be combined as application building blocks to generate a wide variety of 1-8 channel audio applications in consumer or professional audio products.

Class D Amplifiers, what they are, and what they can do for you

 

The audio power amplifier plays an essential role in every system that generates audible sound. For decades, amplifiers have been produced using analog (Class A and AB) designs, which are very inefficient and result in voluminous, heavy, and rather expensive products. The innovation cycle of analog audio power conversion has come to its maturity and hardly any innovation can be made there. This is where class D amplifiers come into play. Switching or Class D amplifier techniques are only at the beginning of their development. These technologies carry a large potential for delivering much higher efficiency and audio performance, making audio products more reliable, of higher quality, smaller size, and involving lower costs.

 

Instead of linear power regulation used in Class AB amplifiers, which leads to energy losses in power transistors, Class D amplifiers use switching transistors that operate only at two stages – “on“ or “off”. Nearly no energy loss occurs at the transistor and nearly all the power is carried to the transducer. While audio amplifiers using class D technologies are only at their beginning, class D technologies have actually been around for decades. Until the 1990s their design and integration characteristics had not been developed to the level necessary for achieving high performance in quality audio and hi-fi applications. It was only in the 1990s that the semiconductor and digital technologies developed far enough to enable enhancement of Class D technologies. ICEpower has pioneered the development of new technologies to enhance Class D amplifiers and bring the audio quality to the level accepted by audiophiles and discerning professionals. This allowed for the subsequent introduction of amplifier power modules for a wide range of audio applications; Active Speakers for both live sound and home listening, ultra-lightweight bass, and guitar amplifiers, energy-efficient subwoofers, and multichannel audio for both commercial and residential installations

1200AS2
125ASX2
300A1

Audio Amplifiers

What can you do with an ICEpower Audio Amplifier

Active Speakers

Active Speakers icon

The days of scratchy audio out of a wall-mounted intercom that looks twenty years out of date are over. Dedicating your best audio amplifier to the listening room or the living room while limiting yourself to a clock radio in the bedroom is a thing of the past. Over the last twenty years, it has become more and more common for houses to be built with speaker wire running to every room of the house. Originally this was done with big and inefficient class AB audio amplifiers with big and heavy toroidal transformers. Running audio all over the house required a huge amount of dedicated rack space that soaked up a lot of power, even when in standby mode.

With today’s best class D amplifiers, what used to take up four rack spaces, a hundred pounds and enough excess heat generated to warm your basement can now be achieved in a highly efficient, single rack space power amplifier.
With today’s modern processing and DSPs combined with best class D amplifiers, you don’t even need multiple preamps or processing units, you can even have one processor provide audio to a whole household. The efficiency of class D power amplifiers allows manufacturers to combine the processing of audio with the audio amplifier inside the same box, without the worry of excess getting in the way of the performance of either. The switch-mode power supply, while generally helping efficiency over toroidal transformers may make its biggest impact by simply being smaller and lighter than a traditional toroidal power supply. The benefits of a smaller size are evident in allowing manufacturers to fit more amplifier power modules or more functions into the same space. The benefits of weight savings of lighter switch mode power supplies are less obvious for products that get installed and likely never moved but are nonetheless significant. Lightweight switch-mode power supplies mean the chassis can generally be of less bulky material. The significant weight savings cuts down on the sturdiness needed for shipping boxes and reduces the cost of the actual shipping itself. This all leads to significant cost savings for the manufacturer, the dealer, and the end customer themselves.

Multi-Channel Audio for the Home

Active Speakers icon

The days of scratchy audio out of a wall-mounted intercom that looks twenty years out of date are over. Dedicating your best audio amplifier to the listening room or the living room while limiting yourself to a clock radio in the bedroom is a thing of the past. Over the last twenty years, it has become more and more common for houses to be built with speaker wire running to every room of the house. Originally this was done with big and inefficient class AB audio amplifiers with big and heavy toroidal transformers. Running audio all over the house required a huge amount of dedicated rack space that soaked up a lot of power, even when in standby mode.

With today’s best class D amplifiers, what used to take up four rack spaces, a hundred pounds and enough excess heat generated to warm your basement can now be achieved in a highly efficient, single rack space power amplifier.
With today’s modern processing and DSPs combined with best class D amplifiers, you don’t even need multiple preamps or processing units, you can even have one processor provide audio to a whole household. The efficiency of class D power amplifiers allows manufacturers to combine the processing of audio with the audio amplifier inside the same box, without the worry of excess getting in the way of the performance of either. The switch-mode power supply, while generally helping efficiency over toroidal transformers may make its biggest impact by simply being smaller and lighter than a traditional toroidal power supply. The benefits of a smaller size are evident in allowing manufacturers to fit more amplifier power modules or more functions into the same space. The benefits of weight savings of lighter switch mode power supplies are less obvious for products that get installed and likely never moved but are nonetheless significant. Lightweight switch-mode power supplies mean the chassis can generally be of less bulky material. The significant weight savings cuts down on the sturdiness needed for shipping boxes and reduces the cost of the actual shipping itself. This all leads to significant cost savings for the manufacturer, the dealer, and the end customer themselves.

Musical Instrument Amplifiers

Active Speakers icon

Traditionally, musical instrument amplifiers for both bass and guitars involved big, heavy toroidal transformers combined with either tubes or class AB output sections. The best sounding, most powerful bass guitar amplifiers weighed in between 40 and 80 pounds. Today, with the advent of the switch-mode power supply and the newest and best class D amplifiers, bass players can enjoy the volume and sound quality in a power amplifier that weighs a tenth of those behemoth ancestors of the past. An amplifier that can fit in the front pocket of a gig bag is a wondrous thing. Small size and lightweight have other benefits, especially when combined with the latest neodymium driver technology. An eight-pound power amplifier combined with a forty-pound speaker that can keep up with an old SVT and hundred-pound “fridge” speaker cabinet turns what was once several trips back and forth from the car to the stage, possible to do in one trip!

For class D amplifiers and guitars, the match was not love at first sight. The compression and distortion created by tubes in a traditional guitar amplifier have always been key to the sound of rock and roll and left little room for switch-mode power supplies and even the best class D amplifiers. While this distortion remains key to some of the best historical guitar sounds, modern technology has led to the development of new, highly capable, digital signal processing, which has enabled skillful developers to model these traditional tube-driven sounds with shockingly high levels of accuracy. What does this mean for guitar players and class D amplifiers? It means that guitar players are no longer limited to the one amp they can fit on stage. It’s being able to choose the best amp for each song! Important to achieving this superior audio quality from the power amplifier. A powerful yet transparent amplifier is needed to get the most out of all the hard work that went into properly modeling those historic guitars amps. The best class D amplifiers are transparent do not impart their own identity on the sound, which makes them ideally situated for bringing these modeling techniques to life.

Class D Amplifiers for Commercial use

Active Speakers icon

Commercial audio shares a lot of common DNA with multi-channel audio for the home, but can at the same time be more complex and somewhat simpler. Commercial audio amplifiers of the past were not always focused on performance. Given the generally lower quality of speaker technology being used in places like grocery stores or shopping malls, channel counts and cost were usually prioritized over sound quality and power, so power amplifiers were more about getting the job done at the lowest cost possible. Modern commercial audio speaker technology has come a long way, in some cases using 2 or 3-way speakers. With this has come a need for the audio amplifier to catch up. The best class D amplifiers match up with commercial audio needs in a variety of ways.

New green initiatives like LEED certification mean efficiency in design needs to be achieved everywhere. It’s not just how efficient the heating and cooling of the building is, but all the potential power draws. A building that needs 128 channels of audio done with multiple older, inefficient power amplifiers, is not only going to consume a lot of power as it operates but waste a whole lot of energy while idling and waiting for activation. The best class D amplifiers and switch-mode power supplies can draw half a watt or less while in standby waiting to activate. Older power amplifiers with traditional technology will draw many times. Commercial audio is sometimes based on 70V or 100V constant voltage power amplifiers. With amplifier power modules capable of supplying these outputs as direct drive, the energy and audio performance losses related to the use of step-up transformers that were needed to power these systems can be a thing of the past. Even better, the best class D amplifiers made with the newest audio IC technology mean you don’t need to stock or purchase dedicated power amplifiers for each use case. Previously a company would need a 70V version, a 100V version, and a low impedance version of the same amp to support all use cases. Now, a commercial audio amplifier based on today’s best class D amplifiers can be made to handle high impedance at both 70V and 100V and deliver low impedance audio in one SKU, allowing one product to handle a wide variety of use cases.

Class D Amplifier Advantages

 

ICEpower® Class D amplifiers have the following advantages:

  • Audio performance on the level with or better than Class AB amplifiers
    • THD performance less than .1% in newest models
  • The significantly higher energy efficiency of audio products
    • ICEpower’s class D amplifiers approach 80% efficiency at just 33% of max power, class-AB amplifiers typically need to run close to max power to achieve similar efficiency 
  • Audio products can be made much smaller and lighter, external heat sinks can be eliminated
    • A 800-watt bass guitar amplifier with an ICEpower power amplifier weighs less than seven pounds, a class AB bass amp of the same power would weigh over twice that while being physically two times larger as well
  • Significantly decreased manufacturing costs
    • Using amplifier power modules from ICEpower simplifies your manufacturing process by allowing you to stock one part for your audio amplifier instead of hundreds of smaller components
  • Higher integration of components is possible
  • Resulting in more design freedom and more attractive products
    • Small, compact amplifier power modules allow for more creative uses of internal space inside speakers and traditional metal chassis
  • Due to the possibility of designing smaller products, more channels can be integrated into a single solution or audio product
    • It’s possible to put up to 16 channels in a 1u rack, which previously took a 2u if not 3u rack space
  • Higher quality of products
    • Increased efficiency means less excess heat, which increases the long term reliability of components like capacitors
  • The possibility of increasing the standard of existing products
    • Up the power and decrease the weight
  • All of this taken together benefits our environment in numerous ways and makes Class D amplification a “green” technology
  • For example, the 10-channel solutions that ICEpower created for Pioneer Electronics’ Susano A/V receiver could not have been developed without applying switching technologies – Class AB amplifiers could not sustain this amount of channels with high audio quality in a single product.

ICEpower Class D Amplifier Efficiency & Performance

Below is the graph of an ICEpower amplifier efficiency compared to the highest theoretically possible efficiency of a Class AB amplifier (the latter calculated under ideal conditions which can never be achieved in reality):

(Green graph: actual measured efficiency of the ICEpower Class D amplifier Conditions: mains 230V AC, load 8 Ohm, frequency 1 kHz sine, 1 channel driven – Red graph: the best theoretically possible efficiency of a Class AB amplifier)

Vice versa, below is the graph of energy loss in an ICEpower Class D amplifier vs. power loss in a Class AB amplifier with the best theoretically possible efficiency.

(Green graph: power loss of an ICEpower Class D amplifier Conditions: mains 230V AC, load 8 Ohm, frequency 1 kHz sine, 1 channel driven – Red graph: power loss in a Class AB amplifier with the best theoretically possible efficiency)

Compare our portfolio of Power Amplifier Modules

Specification 50ASX2 125ASX2 250ASX2 ICEtheater7 80AM2 100AS1/2 300AS1 300A1 700AS1/2 1200AS1/2 Engine400
Power
(4Ω load, rated THD+N)
50 W (SE)
170 W (BTL)
120 W (SE)
450 W (BTL)
230 W (SE) 80 W (SE) 100 W 300 W 300 W 700 W 1200 W 400 W
Power
(8Ω load, rated THD+N)
25 W (SE)
85 W (BTL)
60 W (SE)
225 W (BTL)
120 W (SE)
500 W (BTL)
150 W 160 W (BTL) 50 W 150 W 150 W 350 W 600 W 200 W
Minimum Load Impedance 2 Ω (SE)
3 Ω (BTL)
3 Ω (SE*)
6 Ω (BTL)
3 Ω (SE)
6 Ω (BTL)
3.2 Ω 3.2 Ω (SE)
6.4 Ω (BTL)
3 Ω 2.5 Ω 2.5 Ω 2.5 Ω 2.7 Ω 2 Ω
Upper bandwidth limit (-3dB) 130 kHz @ 8Ω 120 kHz @ 8Ω 120 kHz @ 8Ω 100 kHz @ 8Ω 120 kHz @ 8Ω 50 kHz @ 4Ω 70 kHz @ 8Ω
55 kHz @ 4Ω
70 kHz @ 8Ω
55 kHz @ 4Ω
70 kHz @ 4Ω 50 kHz
(all loads)
100 kHz @ 4Ω
Dynamic range 120 dB(A) 120 dB(A) 120 dB(A) 115 dB(A) 110 dB(A) 109 dB(A) 113 dB(A) 113 dB(A) 117 dB(A) 129 dB(A) 124 dB(A)
Max. amplifier efficiency 94 % 90 %
Max. total efficiency
(amp.+PSU)
81 % 86 % 84 % 83 % 72 % 80 % 84 % 80 %
Power supply Built-in SMPS Built-in SMPS Built-in SMPS Built-in SMPS See notes Built-in SMPS Built-in SMPS See notes Built-in SMPS Built-in SMPS See notes
Supply voltage range 115/230 VAC 115/230 VAC 115/230 VAC 115/230 VAC 85-264 VAC 85-265 VAC 85-265 VAC 22-55 VDC 85-265 VAC 85-265 VAC ±(56-65) VDC
AUX voltage /current ±25VDC/±200mA ±25VDC/ ±250mA ±25VDC/ ±250mA N/A ±12VDC ±(16-21)VDC ±12VDC N/A ±15VDC ±15VDC ±(10-15VDC)
5V standby supply ÷ ÷ ÷ ÷ √ (with 400SM power) √ (7V-10V) ÷ ÷
Short-circuit protection (monitoring)
Temperature protection (warning)
Soft-clipping circuit ÷ ÷
Ext. clip indicator ÷ ÷ ÷ ÷ ÷ ÷ ÷
Ext. Disable / mute control ÷ ÷
Notes 2-channel SE module or 1 channel BTL 2-channel SE module can be bridged into 1 channel 2-channel SE module can be bridged into 1 channel 7 independent channels Part of ICEmatch with 400 SM, up to 16 channels, universal mains supply Powers 300A1 hanger Can be powered from 300AS1, 700AS1/2 and 1200AS1/2 Powers 300A1 hanger Powers 300A1 hanger Can be powered from AUX-plant, Motherboard-1 and mains power supply
Primary applications General-purpose, multi-way system General-purpose, multi-way system General-purpose, multi-way system Home Cinema
Systems / AV
Receivers
Installation amplifiers, multichannel amplifiers, active loudspeakers Active loudspeakers, active subwoofers, amplifiers, bass amps Active loudspeakers, active subwoofers, amplifiers, bass amps Active loudspeakers, amplifiers Active loudspeakers, active subwoofers, amplifiers, bass amps Active loudspeakers, active subwoofers, amplifiers, bass amps