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Audreal PA-20 Class-A Power Amplifier Reviewed
Can a relatively unknown and inexpensive amplifier impress Terry London? Turns out there's lots to recommend with Audreal's latest offering. Read More
Musical Fidelity AMS50 Amplifier
Terry London went looking for "that tube sound" and found a true Class-A operation amplifier from the U.K.'s Musical Fidelity. The AMS50 brings the warmth of tubes but with the control of solid-state. Read More
Wyred 4 Sound mAMP Amplifier
Amplifiers are a necessary piece of equipment, but do they need to be so big? Steven Stone investigates this question with his review of Wyred 4 Sounds's mAMP mono amplifier. Read More
Home Theater Review's Best of 2013 Awards
It's that time of year again. The HomeTheaterReview.com staff has discussed all the products reviewed over the year and decided which ones rated the best. Check out our list of the best of 2013. Read More
Melody Valve HiFi PM845 Mono-Block Amplifier
Terry London takes a look at the Melody Valve HiFi PM845 mono block amplifier. London puts the amplifier through its paces to see if the piece is more than simply audiophile eye candy. Read More
Audio Space AS-6M (300B) Push/Pull Tube Mono-Block Power/Integrated Amplifier
Readers asked Terry London about trying a 300B-based amp in their systems, but not an integrated amp. Terry now has an answer with his review of the Audio Space AS-6M (300B) mono block amplifier. Read More
Melody AN 300B Integrated Amplifier Reviewed
Terry London reviews the Melody AN 300B integrated amplifier. During the course of his evaluation, Terry discovers how your assumptions of how a piece will sound can be totally wrong. Read More
ModWright Instruments Inc. KWA 100SE Power Amplifier Reviewed
HomeTheaterReview.com reviewer Terry London takes a look at Dan Wright's ModWright KWA 100SE power amplifier and puts it to the test to see what this amplifier is really made of. Read More
Red Dragon Audio M500MkII Monaural Amplifier Reviewed
Red Dragon Audio is yet another consumer electronics company to emerge from Utah. Andrew Robinson takes the M500MkII monaural amplifier in for review to find out if this is another Utah success story. Read More
Wyred 4 Sound mINT Mini-Integrated Amplifier Reviewed
Wyred 4 Sound has offered a DAC, preamplifier, and amplifier in one package with the mINT integrated amplifier. Andrew Robinson received the unit for review. And he put it to the test to see what the mINT could do. Read More
Home Theater Review's Best of 2012 Awards
It's that time of year again. The Home Theater Review staff has looked over all of the year's impressive offerings - of which there were many - and narrowed it down to what they believe to be the best of 2012. Read More
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Everything You Need To Know About Audiophile Amplifiers1.0 Overview
2.0 Types of Power Amplifiers
1.0 Overview of Stereo Power Amps for Home Theater
2.1 Class A-B Amplifiers
2.2 Class A Amplifiers
2.3 Tube Amplifiers
2.4 Class-D Digital Amplifiers
2.5 Monoblock Amplifiers
2.6 Power Regeneration
Power amplifiers boost the signal from a preamp to levels that a loudspeakers system can use to make a powerful audio experience. There are various technologies of amplifiers that are use. Most amplifiers are stereo amps thus can boost the amplitude of a stereo audio signal. Mono or monoblock amps are one channel amplifiers and are found mostly on the high end of the amplifier food chain.
2.0 Types of Power Amplifiers
2.1 Class AB
Class AB amplifiers are considered to be a traditional amplifier. They can be either a tube or solid state design. They can be balanced (XLR) or unbalanced in operation. In solid state designs are known for their heat sinks, large torioidal transformers and overall weight. Class AB amplifiers are still the preferred choice of audiophiles because of their powerful, clean sound but digital amplifier designs have made significant improvements in the past few years. At the ultimate level, there are now hybrid audiophile grade class AB/digital amps.
2.2 Class A Amplifiers
Class A amplifiers were at one point the audiophile's choice but their low power, ultra-high heat output, often large size and huge incoming power requirements (240 volt is best for class A amps) have seen them fall out of favor. Their pure sound is hard to argue with but they don't easily keep up with the needs of film sound track playback. They also sound best when "warmed up" for hours. They also have no real ability (by design) to do anything but to run at full power thus their draw from the wall is as strong as you can find. The analogy used by many to describe a Class A amplifier is that it is like a faucet that is turned all the way on.
2.3 Tube Amplifiers
Tube amps are the most alluring and sexy of the amp technologies. The glow of the vacuum tubes, the warm analog sound and the overall musicality make a tube amps something every audiophile should own at least once in his life. Tubes have many drawbacks once you get past the siren song of their appeal. They create a lot of heat. They have very little power compared to solid state (class AB) designs for the same money. Tube amps need constant biasing or adjustments or they will perform poorly in a matter of weeks. They need time to warm up to sound good. They need to have the tubes carefully replaced every few hundred hours of operation.
2.4 Class D Digital Amps
Digital Amplifiers are all the rage these days -specifically ones based around the Bang and Olufsen ICE chip. These amps are ultra-quiet and very low distortion. They are small, create barely any heat yet pump out incredible volumes of power compared to more traditional class AB and tube amps. Digital amps are popular in powered subwoofers and even in some receivers. The downside to digital amplifiers is that they tend to lack the musicality and weight of a traditional amp. They are just missing the musical gravitas at this point of their development. Hybrid digital amps like the Mark Levinson No. 53s are showing some new twists that hope to bridge the two designs to provide the best of both worlds even if it costs $25,000 per channel of amplification.
2.5 Monaural (Monoblock Amplifiers)
Monoblock or mono amplifiers are often the preferred choice of audiophiles and used in the most demanding home theater playback systems. Mono refers to the idea that one physical amplifier is designed to power one audio channel. The main advantage of mono amplifiers is the concept that each channel of audio gets its own power supply thus can provide more accurately and effectively the power needed in an audiophile or 7.1 speaker system as the source material demands. Some audiophile brands make dual or even tri-mono amplifiers which house multiple mono amps in the same chassis yet retain the advantages of the mono design. This normally comes at a significant cost premium. Monoblock amplifiers are commonly found in all varieties of amplifier including tube amps, solid state amps and even class D "digital" amplifiers.
2.6 Power Regeneration Inside High end Amplifiers
The highest end amplifiers on the market today offer their own internal AC power regeneration right inside of the amplifier. You do not need a PS Audio or Audiophile APS Pure Power device for your monster audiophile amplifiers. Top amps from the likes of Krell and Mark Levinson are coming with power regeneration right in the amp itself and the results allow for the last level of extreme performance and refinement for the world's most expensive amplifiers.