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First Watt SIT 2 Stereo Amplifier Reviewed
Terry London explores the SIT 2 stereo amplifier from Nelson Pass' First Watt lab. This $5,000 Class A solid-state amp uses a Static Induction Transistor to produce some of the sonic characteristics of SET tube amplifiers. Read More
Rogue Audio Pharaoh Tube Hybrid Integrated Amplifier Reviewed
Greg Handy reviews the Pharaoh integrated amplifier from Rogue Audio, which combines a tube preamp with a Hypex Class D amplifier and adds a tube headphone amp for good measure. How does this $3,500 integrated amp perform? Follow the link to find out. Read More
Yamaha A-S2100 Integrated Amplifier Reviewed
Bob Barrett explores the A-S2100 integrated amplifier from Yamaha's HiFi component line. This $3,999 90-wpc integrated amp has exceptional build quality and can accommodate a variety of sources. How does it perform? Read on to find out... Read More
Perla Audio Signature 50 Integrated Amplifier Reviewed
In the last year, several of my friends--whose "golden ears" I trust regarding which pieces of stereo gear produce superlative musical performance--came back from both the Newport Show and the Las Vegas T.H.E. Show raving about the virtues of the... Read More
Parasound 275 v.2 Stereo Amplifier Reviewed
Brian Kahn was recently on the hunt for a stereo amplifier to use with his audio distribution system. His search led him to the $595 Parasound 275 v.2, which delivered everything he needed and more. Read More
Krell Solo 375 Mono-Block Amplifier Reviewed
Brent Butterworth reviews Krell's Solo 375 mono-block amplifier, which is part of the company's iBias Series of amplifiers--designed to offer the performance of Class A in a smaller, less power-hungry form. Read More
Raven Audio Nighthawk Tube Integrated Amplifier Reviewed
Terry London explores the $2,295 Nighthawk tube-based integrated amplifier from Raven Audio and comes away highly impressed, with both the product's build quality and its performance. Read More
ATI AT6002 Stereo Power Amplifier Reviewed
Jerry Del Colliano reviews ATI's Signature Series AT6002, a two-channel, 300-watt Class AB amplifier that carries an MSRP of $3,995. To say that he came away impressed would be a huge understatement. Read More
Home Theater Review's Best of 2014 Awards
Home Theater Review presents its Best of 2014 Awards. We've surveyed all the products reviewed over the past year and selected the ones we think are the most compelling. Check out our list and see if your 2014 favorites made the grade. Read More
Pass Labs XA60.8 Mono-block Amplifier Reviewed
It took seven years for Pass Labs to come out with its new XA.8 Series of amplifiers. As Terry London discovers in his review of the new XA60.8 60-watt Class A mono-block amplifier, the wait was definitely worth it. Read More
Peachtree Audio nova220SE Integrated Amplifier Reviewed
Dennis Burger takes a look at the nova220SE from Peachtree Audio. This $1,999 integrated stereo amplifier has everything the audio lover needs, including a 24/192 USB DAC, in a beautifully built cabinet. 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.