Mark Levinson No. 33H Mono-blocks

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Capable of a Prodigious 150W per channel of instantaneous and continuous power into 8 Ohms.

£30,000.00 £8,990.00

Call Choice Hifi on 020 8392 1959 or to enquire about this product!


While the No33H Monaural Power Amplifier is straightforward in everyday use, it includes several design features that are responsi- ble for its outstanding performance. In particular, it defies the accepted wisdom that it is impossible to design a large, powerful amplifier that also has all the finesse of the finest smaller ampli- fiers.

The No33H features a 3.47 kVA low-noise toroidal transformer in a fully balanced power supply—a design that provides separate power supplies for the amplifier’s inverting and non-inverting halves. In addition, each No33H uses four 60,000 μF low-ESR capacitors.

Heavy bus bars enhance the efficiency of power distribution with- in the amplifier and eliminate variances introduced by the wiring harnesses commonly found in even high-performance amplifiers. High-frequency power supply bypass is accomplished using indi- vidual PC boards that use 32 components of several different film types. The resulting uniformly low power supply impedance seen by various circuits within the No33H lays the foundation for mas- sive power and extraordinary finesse.

The detrimental sonic effects of noisy, unbalanced AC power supplies are widely known. Commercially available passive AC line conditioners provide some measure of AC power filtering and surge protection for line-level components such as preamplifiers and digital audio processors. However, these line conditioners cannot handle the large, instantaneous currents that power ampli- fiers require. In effect, the line conditioner becomes a bottleneck in the otherwise free flow of power through the amplifier and loudspeakers, greatly reducing the dynamic impact of the signal.

To avoid these performance bottlenecks, the No33H uses built-in line conditioning techniques. When AC power is delivered to the No33H, it is rectified, filtered, and regulated into positive and neg- ative DC voltages. A portion of this DC power is used to drive an oscillator circuit that regenerates a pure 60 Hz sinewave. This sinewave is then used to power a separate power supply dedicated to all voltage gain stages. The dedicated power supply benefits from a truly balanced source as well as the total elimination of AC noise and fluctuations. As a result, the No33H’s critical voltage gain stages operate in a truly optimized environment, passing a musical signal with outstanding low-level resolution and detail.

A truly balanced input topology eliminates the need for an input buffer amplification stage, allowing the first stage differential amplifier to be driven directly by the source. Matched impedances are presented to the source and both signals travel through identical circuit paths.

Meticulous attention to the layout of the amplifier, including careful mirror-imaging of circuits to cancel magnetic fields, was essential to minimize magnetic field distortions that can occur with such a massive power delivery system. The input signal remains balanced, and rejection of common mode noise and distortion is achieved in the loudspeaker’s voice coil.

The No33H operates like a true voltage source—maintaining the appropriate voltage at a given time (based on signal demands) without particular regard for the current demands of the associated loudspeakers. Whether the loudspeakers require a 1 or 50-amp cur- rent, the No33H will deliver.

Forty output transistors distributed throughout the four main heat sinks conduct and control the flow of power to the associated loudspeakers. Ten complementary pairs of output transistors are used in both the inverting and non-inverting output stages.

No known high-quality loudspeaker can continuously absorb the full power of the No33H; but many loudspeakers require these extreme bursts of power on a short-term basis when reproducing music at realistic levels. The No33H provides these short bursts without creating power supply sag or altering sonic performance. Its imperturbable nature is reflected in the authority and control with which it reproduces musical signals.

Brand: Marjk Levinson

Model Name/Number: No.33H Mono-blocks

Price (RRP): £30000

Choice Hifi Price: £8990

Product Information:

Rated power output:

• 34.6 Vrms (150 W) @ 8Ω

• 34.6 Vrms (300 W) @ 4Ω

All of the above power ratings were measured as continuous (rms) power from 20Hz–20kHz with no more than 0.3% THD.

Frequency response:• Within 0.2 dB from 20Hz to 20kHz

Signal-to-Noise ratio:• –75 dB CCIR

Input impedance:• 100kΩ (balanced) • 50kΩ (unbalanced)

Voltage gain:• 26.8 dB

Input sensitivity:• 1.59V (full-rated output)

Power consumption:• 360W in idle; 130W in standby

Mains voltage:• Determined by the requirements of the country for which the unit was manufactured; cannot be reset by dealer or user

Overall dimensions:• See “Dimensions”

Shipping weight:• 220 pounds (100 kg)

Connector complement:

• Four custom binding posts
• One 3-pin XLR balanced input connector
• One RCA input connector
• Two 1⁄8″ mini-jacks for remote turn-on
• Two Mark Levinson communications ports on RJ-11

• One captive high-current AC receptacle

Output impedance:• Less than 0.05Ω from 20–20,000Hz

The correlation between published specifications and performance is unreliable. Measurements of your amplifier yield excellent results by any standards. However, only those specifications that apply to its actual operation are included here.

All specifications are subject to change at any time.

User Manual here:


Age: 15

Condition: 9/10

Voltage: 220/240/50Hz

Finish/Colour: black/ Silver

Packaging? Yes

Accessories? Yes

Item Location: In Stock

Status: Second Hand

Dimensions 5708473 cm