Mark Levinson No. 436 Monaural Power Amplifier 
Home Theater Power Amplifiers Mono Amplifiers
Written by Bryan Southard   
Wednesday, 01 January 2003

Introduction
When purchasing automobiles, you are presented with a selection that varies from simple low-cost transportation merely designed to supply the most basic features and a means from point A to point B, to vehicles that are the very essence of performance and artistic expression. When purchasing audio/video products, you have an equally enchanting array of choices, designed to fit every budget and performance desire. The Mark Levinson No436 is a product designed for the audio/video enthusiast who demands nothing short of the highest performance that money can buy.

Madrigal is no stranger to this level of performance with lines that include Revel and Proceed and are no stranger to me, as I own and use Revel Salon loudspeakers and the Mark Levinson No32 line-stage preamplifier in my reference system. The No436 is a rack-mountable 350-watt Class AB monaural power amplifier that measures 15.5 inches in width, 20.5 inches in depth and nearly a 4 RU high rack height of six-and-three-quarters inches. Each amplifier weighs 85 lbs. and has a retail price of $6,250.

The importance of the power amplifier is paramount in an A/V system as it is the last link in your electronics chain and the power plant needed to drive your favorite (and often demanding) loudspeakers. It is responsible for taking the low-level signal from either your line stage or A/V preamp, and making it powerful enough to drive your loudspeakers – not a trivial task. Monaural amplifiers can have many sonic benefits over a stereo amplifier. Firstly, a mono amplifier is designed to drive a single speaker. It doesn’t share power supplies and transformers, so they are capable of supplying more instantaneous current to your speakers. Mono amplifiers also eliminate any potential interaction between audio channels. In a multi-channel audio/video system, this becomes an enormous advantage, as you can connect an amplifier to each discrete audio channel.

When selecting a power amplifier, perhaps the most important consideration, other than cost, is the amount of power that your loudspeakers needs to perform at your desired volume. The lower the sensitivity of your loudspeakers are and the larger your room gets, the more power you will need. For instance, my Revel Salons are rated at 86dB SPL (sound pressure level) @ one watt. What this means is that your speakers will need one watt of power to produce 86 dB of sound at one meter. For instance, my Revel Salon’s are rated at 86dB SPL (Sound Pressure Level) @ 1 Watt. What this means is that your speakers will need one watt of power to produce 86 dB of sound at 1 meter. For each 3dB increase you will need double the power. In my case, this calculates to 256 watts of necessary power to rev my Revel Salons to 110dB of SPL, a volume that my system hears during nearly all of my energetic listening sessions. As an audio enthusiast rule, if you can afford the abundance of power, go for it. Power provides more than just volume – it provides sonic control and ease along with system protection. It is much harder to blow drivers with a system that is not distorting – even at high levels.

The Mark Levinson No436 is packaged in a newer, sleeker suit than earlier amps like the Mark Levinson No336 stereo amplifier. With the surge of multi-channel entertainment and the need for more than a single stereo amplifier, the No436 mono amplifier was produced with space savings in mind. Its minimalist package is sized to fit in a rack and take up as little rack space as possible. The front of the chassis has two aesthetically-pleasing silver aluminum wings that are connected to the main black-colored chassis via standoffs. Additionally, the Mark Levinson logo and the power and standby buttons finish off the front panel. At the rear of the amplifier are handles to assist you in moving the amplifier, inputs for both balanced and single ended cables, and a variety of communication connections. Gone are the oversized external heatsinks that once identified a Mark Levinson amplifier, replaced by a much more sophisticated heat exchange/thermal management system. A row of slots perpendicular to the face plate are visible only from the top of the chassis. At lower temperatures, these slots cool the amplifier with natural convection. As the temperature of the amplifier rises, fans draw air through the cross-cut heat sink, which forms an isolated tunnel, thereby preventing dust from being drawn into the amplifier which could ultimately compromise performance and reliability. These thermally controlled fans adjust their speeds based on necessary cooling requirements. Because the fans run at their highest speeds when you are driving the amplifiers the hardest, you are virtually assured that they will never be heard. I could never discern the sound of the fans in my system, whether the amplifiers were operating or idle.

Features
The No436 employs Madrigal’s proprietary Adaptive Biasing Output Stage. This philosophy was originally introduced in the Mark Levinson No33 Reference Monaural Amplifier many years ago and has since found its way into the 300 and 400 series amplifiers. Although all Class AB amplifiers have a biasing stage, Madrigal’s has been designed to greatly extend the amount of available Class A amplification. With the No436, the devices are turned off gradually, eliminating the risk of reverse biasing and allowing for much reduced crossover distortion.

The No436 is a fully balanced design. It utilizes 16 output transistors to control the power flow to the loudspeakers. This provides eight matched sets per amplifier. Internally, the No436 uses pure oxygen-free copper buss bars for power distribution, to alleviate noise and power inconsistencies seen with typical wire harnesses.

For control and automation, the No436 provides a DC trigger input, allowing for external control of its power and standby modes. There are also DC trigger inputs, allowing you to control multiple amplifiers from a single control source. The No436 supplies link-ports for communication and automation between the No436 and other Mark Levinson components.

Additionally, the No436 provides PHAST and RS-232 communication ports for compatibility with other external control systems. The No436 provides several operating stages: Off, Sleep, Standby and On. These pre-listen stages provide a variety of readiness conditions, each with a different level of power consumption. In standby mode, your amplifiers will need minimal warm-up, although they will consume more power than that in the sleep and off modes.

The Music
Throughout the audition period, I was impressed by the way these monstrously powered amplifiers could reproduce the seductiveness of vocals. An excellent example came from Tori Amos’s latest, Scarlet’s Walk (Epic). In the cut “Wampum Prayer,” the percussion intro was notably clear and airy. The piano, an instrument that is historically difficult to reproduce with accuracy, was placed distantly in the stage, yet sounded remarkably real. The No436 was able to reproduce both the strike of the hammers and the decay of this warm instrument as well as I have ever heard on any system with any recorded piano. Amos' vocals possessed fantastic inner detail and complex vocal timbres. In fact, I have yet to hear an amplifier that I felt recreated the complete vocal experience better than these amps. I have long loved tube amplification for its ability to breath life and midrange purity into my music. I was willing to accept the many compromises of tube amplification just to experience the sheer reality and seductiveness that tubes can provide. The No436 amplifiers had a quality that made me forget about the stereotypical differences inherent in the two designs, providing extremely transparent instrumental and vocal textures. In the song “Ms. Jesus,” Amos' voice was crisply detailed and infinitely resolute, down to the finite crunch in her vocal cords.

Moving from the clean side of vocal perfection to the awesomely filthy side of grunge, I loaded Mad Season’s Above (Columbia). In the song “Artificial Red,” the No436’s treated me to a unique combination experience of low-end authority and sweet yet transparent high frequencies. This recording is nasty enough that I was never wowed completely but it highlighted some specifically good characteristics of the No436s. The snare drum was tight, with a very natural ring and impending decay, and the guitar tone is simply infectious. In the song “Long Gone Day,” the saxophone was placed beautifully in the depth of the stage. Overall, this recording had better weight throughout the midband than I have heard from a solid-state amplifier. As I found with other recordings, Lane Staley’s vocals had a gloriously natural texture.

Off to some multi-channel music I went, with Lyle Lovett’s Joshua Judges Ruth (DTS Entertainment). For those enabled with the capability to play multi-channel DTS, this recording is truly special in every way, and perhaps the best sounding popular recording ever pressed to a disc of any kind. It unites the rare combination of a fabulous artist and performer, along with a beautifully done recording. The No436s had me listening to these tracks louder than ever before. In the opening cut “I’ve Been to Memphis,” the No436s were presented with the challenge of maintaining transparency and depth in the piano, yet providing power and low-frequency authority with the introduction of the drums. Even at volumes that could be heard three doors down, the instruments remained separated and without the slightest congestion. This recording through the No436 amplifiers was nothing short of sensational.

In Ridley Scott’s "Black Hawk Down" (Columbia/TriStar Home Entertainment), I put the 436s to the test. I listen to movies very loudly and what I have found with other high-powered, solid-state amplifiers is that the less than perfect soundtrack information could sound brittle in the upper frequencies. The No436’s didn’t. Many amplifiers sound great and lack annoying artifacts on well-recorded audiophile music, but to take something like a shoot-'em-up soundtrack that is played at extreme volumes yielding sweet and detailed sound is extraordinary. It made me want five No436s (one for each speaker) to truly realize the potential of the soundtrack. With the absence of a subwoofer, the helicopters still sounded surprisingly powerful and didn’t provide even the slightest signs of fatigue. Details such as the sound of copter blades piercing the wind and bullets flying by, were richly detailed, more so than with any other amplifier that I have auditioned to date. If I were to use more superlatives here, I might lose credibility with you. Just make sure to bring "Black Hawk Down" with you when you audition amps at this level and you’ll see what I am talking about.

My listening experience with the No436 amplifiers showed that they had an extremely quiet and richly detailed top end. They did not have the ultimate high-frequency transparency of the Linn Twin that I reviewed a couple moths back at $9,000, yet the No436s had an overall better balance. Although the No436s had less high-frequency information than the Twins, the high frequencies were nevertheless more pleasurable for my taste. The No436s didn’t have quite the sheer low-end power of the Pass X350, yet the No436s were more enjoyable than the Pass X350 in nearly every way. Taking all the techno mojo from the equation, the No.436s made me want to listen to real-world music and blockbuster movies more and at higher volumes.

The Downside
The high frequencies of the No436 could be on the soft side for adrenaline junkies (like AudioRevolution.com publisher Jerry del Colliano). The low frequencies are likewise a bit mellower, albeit very controlled and solid, unlike the Mack truck-slamming bass that the Pass and Krell amplifiers provide. For me, the No436’s response was exemplary and preferable to either of the aforementioned amplifiers.

As always, before laying out the hard-earned dough, give them all a listen

Conclusion
The amplifier is a simple component when compared to feature-laden A/V preamps and many digital products, yet they have the job of a mighty workhorse. They should not be the forgotten component, but rather the foundation of your A/V system. The Mark Levinson No436 mono amplifiers are the best amps I have heard in my system and, in my opinion, are the best-sounding amplifiers in their price class. Del Colliano might prefer the comparably-priced monaural Krell Mcx 350s, but for my system, I stand by my comments. Also note that I am backing up my superlatives with my wallet – I bought the pair for my reference system.

I could go on to say in detail why I made the purchase, but I would rather opt for the simple explanation that they made me enjoy every aspect of my listening experience more than I ever had before. They are infinitely involving and brought me closer to my music. Although expensive for the pair, and even more so for the five or seven if you are so inclined to obtain them all for your A/V system, they are worth every penny.
Manufacturer Mark Levinson
Model No. 436 Monaural Power Amplifier
Reviewer Bryan Southard





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