Power AmplifiersPower Amplifiers
Pass Labs XA-100.5 Pure Class A Monoblock Power Amplifier
- Written by John E. Johnson, Jr.
- Published on 04 April 2011
Most amplifier manufacturers produce power amplifiers that are biased as Class AB, meaning that they run a few watts in Class A and the rest in AB. This is usually a push-pull configuration, and the AB moniker refers to a slight overlap in the + portion of the waveform that is delivered by one section of the amplifier with the - portion handled by the other amplifier section.
Emotiva XPA-3 Three-Channel Power Amplifier
- Written by Ross Jones
- Published on 31 March 2011
The term "separates" was once reserved for the upper crust of the home theater world. Only those with the most discerning ears (and fattest wallets) considered purchasing a separate preamp/processor and multi-channel power amplifier. That time has long gone, thanks in part to the rise of Internet-direct firms such as Emotiva. They manufacture monoblocks (single-channel amplifiers) and multi-channel amplifiers, up to the XPA-5 which has five channels. The current review explores their three-channel amplifier, called the XPA-3.
Spectron Musician III Mk2 Class D Stereo Power Amplifier
- Written by John E. Johnson, Jr.
- Published on 21 October 2010
Spectron has been manufacturing Class D amplifiers since before most people even knew what they were. I remember meeting John Ulrick, Spectron's designing engineer, many years ago at a CES, and seeing his first model. I had no idea how it worked, but what impressed me was that it was extremely powerful, yet relatively small. Class D amplification technology has come a long way since then, but definitely, Spectron was a pioneer. In this review, we take a look at the Spectron Musician III Mk2, which will deliver 600 watts rms per channel into an 8 ohm load, and is rated into 2 ohm loads. The amplifier weighs 52 pounds.
Classe CA-M600 Monoblock Power Amplifier
- Written by John E. Johnson, Jr.
- Published on 21 February 2011
Classé updated their Delta power amplifier series in late 2010, including the CA-M400 which is now the CA-M600. The entire amplification signal passes on a single circuit board, and they have introduced a new cooling system called ICTunnel™, which utilizes a fan on the inside front panel of the amplifier that draws aire into the chassis and over some fins that absorb heat fromt the circuit boards. In use, I found the fan to be whisper quiet, with just a gentle breeze coming from the front amplifier port. This kept the entire chassis cool, but also, the temperature of the circuit board is electronically controlled by adjusting the fan speed, to optimize the performance, which turned out to be stellar.
Earthquake Sound Cinenova Grande Multi-Channel Power Amplifier with Class A Bias
- Written by John E. Johnson, Jr.
- Published on 01 October 2010
We reviewed the Earthquake Sound Cinénova Grande multi-channel amplifier several years ago, but it has gone through some changes in the circuitry, including significantly higher output, so we thought it was time to revisit this legendary product. It is available with up to seven amplifier modules, each capable of delivering 360 watts RMS into 8 ohms. Our review unit came with five modules.
Mark Levinson No 53 Monoblock Power Amplifier
- Written by John E. Johnson, Jr.
- Published on 06 December 2010
Mark Levinson is a state-of-the-art brand, whose products are purchased by consumers whose bank accounts are also state-of-the-art. Levinson makes no apologies for their prices, nor do they have to justify them. The axiom is simple: If you want the best, it costs a lot. The latest addition to their power amplifier line takes a huge leap from the previous designs, which were Class AB, and which usually were biased well into Class A operation. The Mark Levinson No 53 is a monoblock power amplifier that is a switching design, i.e., the output stage is operated in switching mode, but it is unique in that it interleaves eight switchers to produce a fully balanced output, at a realized switching frequency of 4 MHz.
Bryston 3B SST2 Stereo 150 Watt per Channel Power Amplifier
- Written by John E. Johnson, Jr.
- Published on 13 September 2010
Following on our review of the Bryston 14B SST2 stereo power amplifier, we now take a look at its smaller brother, the 3B SST2, which delivers 150 watts rms x 2 into 8 ohms. Although it won't necessarily rattle the wall studs like the 14B can, it provides good solid power at very low distortion.
ADCOM GFA-555se Stereo Power Amplifier
- Written by Rick Schmidt
- Published on 02 December 2010
The original ADCOM GFA-555 stereo power amplifier hit the market in 1985. Standby for math calculation. That's 25 years ago. Enough time for a digital music revolution (maybe peaking now). Enough time for the Rolling Stones to release 11 new records (28 for Neil Young). Enough time for most rock bands to burn out, fade away and then stage a comeback. And, enough time for a hifi manufacturer to come and go as well. Here, we review the latest iteration fo this classic, called the GFA-555se.
Mystere pa21 Stereo Tube Power Amplifier
- Written by John E. Johnson, Jr.
- Published on 21 June 2010
Durob Audio is a company in the Netherlands that markets PrimaLuna tubed audio components, including integrated amplifiers, power amplifiers, and a CD player that has a tube-based clock. It also has a discrete output stage with triodes running in pure Class A. Conventional CD players use op-amps in the output stage. Although the tube output stage and op-amp output stage sound different, one doesn't necessarily sound "better" than the other, although tubeophiles would all opt for the "better". We reviewed the PrimaLuna DiaLogue Two integrated amplifier in December, 2009.
With the introduction of Durob Audio's Mysterè line, we now review the Mysterè pa21, which is a 55 watt per channel stereo tube power amplifier. The Mysterè line goes beyond the PrimaLuna line with larger transformers, more power supply capacitance, and an auto-bias circuit that lets the consumer choose between using KT88's or EL34's as the output tubes.
Wyred4Sound SX-1000 Monoblock Power Amplifier
- Written by Stephen Hornbrook
- Published on 08 November 2010
Wyred4Sound has entered into the high end audio market with plenty of experience behind its doors. Born from the skilled minds and hands of EJ Sarmento and Rick Cullen of Cullen Circuits, these two have been providing high end components for the audio industry for years. Rick used to be the production manager for PS Audio, until in 1990 he started Cullen Circuits- a provider and consultant to companies such as PS Audio, Genesis Technologies, Camelot and more. In this review, we take a test drive with their SX-1000 Class D monoblock power amplifier.
Bryston 14B SST2 Stereo 600 Watt per Channel Power Amplifier
- Written by John E. Johnson, Jr.
- Published on 03 June 2010
Bryston, renown manufacturer of amplifiers with a 20 year warranty, markets products with a full gamut of power output ranges. The 14B SST2 is a stereo power amplifier rated at 600 watts per channel output into 8 ohms. That's a lot of power. Is all that power useful? Is it necessary? Read our review and discover.
