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 N^o 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.

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.

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.

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.

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.

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.

Over the past decade, a lot has changed on receivers that we buy for home. We've gone from S-Video to Component to HDMI for video, replaced 6 RCA cables for 5.1 audio with a single digital cable, to having it integrated in the HDMI signal along with video. Receivers have added all sorts of new functions with better on screen menus, room correction, Ethernet ports for streaming media and firmware upgrades, and we have also moved from 5.1 channel audio, to 6.1, then 7.1, and now all the way to 9.1 or greater when using Dolby ProLogic IIz or Audyssey DSX. However, one thing on receivers has barely changed when I look back over the spec sheets: weight.

Bryston is known for building some of the most sought-after, powerful and dependable amplifiers in the business. For over 40 years, they have provided an incredible 20 year transferable warranty, practically unheard of in this or any industry. If you find one (that is if you can find one) on the used market, chances are it will still be under warranty. Their rare appearance on the used market has as much to do with their sound quality and dependable (high) power delivery as it does with their warranty. Here, we review their 9B SST², which is a five-channel (5 x 140 watts) power amplifier.

PrimaLuna is a Dutch-based company that released its first products, the ProLogue One and ProLogue Two integrated tube amplifiers in 2003. Then, in 2006, they released the ProLogue Three preamplifier, and ProLogue Five, Six, and Seven power amplifiers. Late in that same year, the PrimaLuna DiaLogue series hit the market, which had the DiaLogue's basic features, but with upgraded parts and additional capabilities. Here, we review the DiaLogue Seven, which is a monoblock power amplifier, capable of delivering 40 watts RMS in triode mode, and 70 watts RMS in ultra-linear mode (see review for an explanation of what this means). The bottom line is that the PrimaLuna DiaLogue Seven monoblock is more than capable of delivering a clean, detailed, and lush sound (ah, those tubes are responsible for that).

What do a 30 watt stereo solid-state amplifier and a 500 watt solid-state monoblock have in common? A lot, it turns out. The seemingly diminutive Pass Labs XA30.5 weighs 75 pounds, has an enormous toroidal power transformer, and uses 20 output transistors to deliver 30 watts of pure class A power. It turns out these specs are similar, or in some cases, better than my recently reviewed Emotiva XPA-1 monoblocks. The XA30.5 proves that rated power is by no means everything. In fact, if you have speakers of even moderately high sensitivity, the XA30.5 renders any discussion of power output irrelevant. When paired with the right speakers, this may be one of the best amplifiers there is, regardless of price.