Featured Articles

We've all seen amplifier companies tout that their amps are "high instantaneous current". Using the very basic principle governing electricity called Ohm's Law (V=I*R), how could it be possible that 100 watt amp has "higher current" than another 100 watt rated amplifier? This very subject has come up on numerous audio forums including the Audioholics forum, and this article explores that topic as well as the history of how the term "high current" became popularized by some manufacturers. We do some basic calculations to illustrate just how nebulous this specification often really is.

There has been much discussion on the major audio forums lately regarding A/V receivers and multi channel amplifier power output capabilities as well as their abilities to drive low impedance loads. Much of the controversy steams around the infamous "All Channels Driven Test" which simulates a best case test load in a worst case environment and by all intents and purposes an unrealistic real world scenario. As a result, we have come up with a standard for measuring amplifier performance that deals with various types of power tests as well as other metrics that directly affect sonic performance and how the amplifier can sound powering various types of speaker loads.

This article explores why the impedance switch exists on some A/V receivers and its intended purpose, including tradeoff’s when following the manufacturers recommended settings. Know the facts when purchasing and setting up home theater equipment. Most importantly, step back and evaluate how you are using your system and make adjustments accordingly to avoid robbing your speakers of power.

Ever wonder how an amplifier works at a very fundamental level? Alan Lofft, Resident Expert of Axiom Audio takes us on a tour of traditional linear amplifiers as well as the newer more sleek Class D designs. Various types of Class D design approaches are discussed including feedback topologies and their implications on audio performance and efficiency. The similarities and differences of traditional Class D amplifiers compared to Axioms new A1400-8 multi channel amplifier is reviewed. Learn what makes these amplifiers tick and why it’s cool in more ways than one to get your hands on the future of high end audio amplification that is powerful, efficient, and lightweight compared to their analog predecessors.

It’s been a few years since our controversial release of “Attack of the Clone Processors” and we felt it was time for a sequel to our blockbuster hit editorial. Engineering a product from the ground up, especially one as complex as a switching amp, takes time and money with the end result often not being as good or cost effective as what can be bought off the shelf like these ICE modules from Bang & Olufsen. I can count the number of manufacturers producing their very own Class D designs and still have a finger left to point at all the copycats. Overall this seems to be a good design approach for manufacturers unwilling or unable to do their own developmental work if cost and full disclosure of performance is kept in check. It’s up to you the consumer to decide if paying a premium price for name brand, exotic accessory parts and cosmetics is worth the investment. Just don’t let anyone tell you that regardless of price, you are buying anything other than a clone amplifier, albeit a reasonably well engineered one.

Ever wonder why the boom box you bought at Best Buy has a higher power rating than your dedicated two-channel power amplifier? Amplifier power ratings are usually honest in Hi-Fi equipment, but become very silly when it comes to the 'mass market' systems and even some of the latest Class D amplifier offerings. Few amps have a dynamic headroom of better than 1 or 2dB, and the greater the headroom, usually the cheaper the power supply for the rated power. This article explores the history of power ratings for consumer audio and also busts the myth about 'RMS' power.

With new A/V receiver models being released by the major manufacturers every 8 months or so, consumers flock to them for promised improved performance and features. But are you really getting better performance with the newer models? Or are you trading amplifier quality for features? This article will be primer for what’s to come in our verification testing to better answer these questions. Stop and think if the model you currently have meets the performance vs feature balance that is right for your needs and how the newer so called “improved” model fits into that equation. All the features in the world can’t replace clean undistorted dynamics which we believe makes up most of the WOW and magic in the newer HD audio formats.

Alan Lofft, Axiom Audio's Resident Expert, took a series of the most commonly asked questions he received about amplifiers, and transformed his answers into an informative editorial. In this article you will find answers to the importance of amplifier weight and how it relates to quality, how an amplifier works, what the different classes of amplifiers are (ie. class A, A/B, D, etc), and the most important attributes of amplifiers that govern their real world performance.

Can Your Amp Truly Deliver What It Claims? Just how valid is the All Channels Drive (ACD) power test that many home theater publications use to measure amplifier power? This article cuts through the nonsense of this hotly debated (and often misunderstood) topic. We explore exactly how print magazines and manufacturers are rating their amplifiers power output with all channels driven, the relevancy of these tests and how it impacts real world performance.