Introduction to Amplifier Reviews

Amplifiers can be considered in three subcategories: Preamplifiers, Integrated Amplifiers and Power Amplifiers.

Preamplifiers handle small signal switching and gain or attenuation (volume control). In many cases, these products have balance controls, equalization or even automated room correction. Preamplifiers may also contain phono preamps, DACs, video switching, headphone amps and streaming/playback of digital files to name just a few additional features you may encounter. There are several different circuit topologies on the market, some are quite simple and others very complex. Preamplifiers do not have amplification to drive speakers and for this purpose you will need to add a separate power amplifier.

Integrated Amplifiers : take a preamplifier, add a stereo amplifer in the same chassis and you have an integrated amplifier. Though more convenient, this is widely regarded as less desirable than having a separate preamplifier and power amplifier as this isolates the small and large signal sections far better than with integrated amplifiers. Integrated amplifiers can have all the features of preamplifiers. They are also available in solid state, vacuum tube or hybrid designs.

Power Amplifiers provide the power to drive your passive loudspeakers. Like all the other amplification components, they can come in a variety of styles. It is of the utmost importance to select an amplifier that is compatible with your speakers and with sufficient power to fill your room with music.

All our reviews feature breakdowns of the product design, product setup and notes on the performance with subjective listening impressions. Most of our reviews also include our own objective bench tests which tell you how much distortion an amp has, its frequency response and, in many cases, its maximum power output, irrespective of manufacturers' claims.

Review Categories

Amplifier Reviews

Pass Labs INT-150 Integrated Stereo Amplifier

Pass Labs is renown for their high end preamplifiers and power amplifiers, but they also have integrated amplifiers as well, which include the INT-30A and the INT-150. Here, we review the INT-150, which, as you can imagine from the model number, outputs 150 watts x 2 (into 8 ohms). It has the same massive build quality as the other Pass components I have reviewed, and also, its own distinctive sound, as I have found with the others.

Bryston BP17 Stereo Preamplifier

Bryston is the only high-end audio company I know of that offers a 20 year warranty on its products. They manufacture some very expensive preamps and power amps, but even the least expensive product carries that warranty. Why? Because they have massive build quality. The BP17 stereo preamplifier exemplifies that approach, and it is in the middle of their preamplifier line-up, which includes the BP6 and BP26.

Funk LAP-2.V3 Preamplifier

It is becoming increasingly popular for high end audio buffs to use pro studio gear in their home systems. This preamp from a German manufacturer that makes pro gear is in keeping with this trend. As a matter of fact...

Burson Soloist Headphone Amplifier

Burson Audio hails to us from Australia, bringing its own design philosophy, "Less is More," to high-end headphone amplifiers. They gained notoriety with the successful HA-160 headphone amp, a pure class A design with an output of 250mW. Here, we review the Burson Soloist Headphone Amplifier, with a specified output of 4 watts.

Parasound Halo A 31 Three-Channel Power Amplifier

Parasound has been making their Halo line of products for quite a few years now, but they are not one to make updates for the sake of change. Their A21 and A51 amplifiers have been unchanged since they debuted and remain a mainstay. The A 31, reviewed here, is a three-channel (250 watts x 3) power amplifier.

Pass Labs XP-10 Stereo Preamplifier

 In the past, we reviewed the Pass Labs XP-20 and XP-30 stereo preamplifiers. Now, we come full circle with a review of the remaining member of their preamplifier trio, the XP-10, which is the least expensive model. It is fully balanced, and has a slightly different sound character compared to the other two, which also sound different from one another. All three are great products, so you can choose based on price and/or sound characteristics.

 

 

NAD M3 Integrated Stereo Amplifier

If you look at the specs of most stereo integrated amplifiers, the rated RMS power output is between 60 watts and 120 watts per channel. This is lower than the power output of outboard power amplifiers, which typically are about 125 watts to 300 watts per channel. Monoblocks go all the way up to 2,000 watts output. One of the main reasons for this is that in an integrated power amplifier, the preamplifier circuit is situated very close to the power amplifier. Keeping the high voltage, high current power amplifier signal from inducting noise into the preamplifier circuit is difficult. NAD apparently has solved this problem with the introduction of their M3 Integrated Amplifier, which has a rated output of 180 watts per channel, at 0.004% THD+N, and clipping (1% THD+N) at 220 watts.

Anthem P2 Two-Channel Power Amplifier

Anthem's statement multi-channel power amplifiers are called the P series. They come in two versions, a five-channel (P5) and a two-channel (P2). My home theater test lab has a 200 watt x 5 amplifier which works great for the majority of applications, but it is driving electrostatic speakers (ESLs), and for a handful of Blu-ray movies, the amplifier will go into protect mode when at high volume, because ESLs typically have a very low impedance (1 ohm) in the high frequency range.

Classe CP-800 Stereo Preamplifier

Classé's new CP-800 is a high performance ("High-End") stereo preamplifier, but it is not just yet another preamp with minor changes from previous models. This one has the option of switching in some DSP that adds several EQ bands and dedicated stereo subwoofer outputs. If you don't use the DSP, it's not in the signal path, and you can still call yourself a "purist" audiophile. Have no doubts; this is a very unique product, and the performance is stellar.

Pass Labs X1000.5 Monoblock Power Amplifier

We have reviewed several Pass Labs products in the past, and I finally decided to get a pair of what they call "Room Heaters", i.e., the X1000.5. These monoblock power amplifiers are rated at 1,000 watts rms into 8 ohms. They are similar in physical design to the XA200.5, but the XA200.5's are biased into Pure Class A, while the X1000.5's are biased about 80 watts into Class A, with the rest as AB.