Mark Levinson No. 536
Mark Levinson No. 536
Mark Levinson No. 536

Mark Levinson No. 536: Discrete Pure Path mono amplifier

The Mark Levinson No. 536 is a fully differential, fully discrete Pure Path mono amplifier that can effortlessly drive virtually any speaker with impeccable fidelity, musicality, and openness. Signal path with direct connection; highly linear design with low feedback; The voltage gain and main gain stages operate in Class A mode, while Ethernet, RS-232 and USB connections for monitoring and control provide the integration features required by a modern system. Housed in extruded 6063-T5 aluminum alloy, the Mark Levinson No. 536 amplifier features exceptionally high precision assembly with astonishingly tight tolerances. Housed in 6000 Series aluminum alloy, the No. 536 amplifier, like all Mark Levinson equipment, is designed and assembled by hand in the USA.

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The audio circuitry in the Mark Levinson No. 536 amplifier is optimized for the best possible performance in open-loop operation. As a result, the need for negative feedback is very small, and its magnitude can be adjusted to achieve certain measurable or subjective results. The open-loop gain and bandwidth of the circuit were carefully tuned using precision resistors and compensation capacitors, and then additional precision resistors were used to provide the feedback network.

The Mark Levinson No. 536 amplifier features balanced and unbalanced inputs that allow it to be used with virtually any preamp or source playback device with variable output. For reliable, tool-free speaker connections, the 536 features two pairs of gold-plated screw terminals with Mark Levinson Hurricane locking screws, allowing for both standard and bi-wire speaker connections. In the USA and countries other than Europe, cables with banana plugs may be used. System integration is possible via Ethernet/IP networking, RS-232 port, USB connection for control and configuration from a web page, and 12V triggers.

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Mark Levinson components are developed within the framework of the Pure Path amplifier circuit design concept, which actively uses a circuit design element called “cascode”. The cascode was originally invented to expand the bandwidth of tube circuits in radios, and Mark Levinson engineers use cascodes in Pure Path circuits to both increase the operating frequency range and improve linearity across the entire range. The cascode consists of two transistors combined in such a way that they operate as a single component device, like a single transistor, which has the desirable characteristics of each of the constituent transistors, but which eliminates the undesirable properties of each of them.

Mark Levinson engineers began designing the amplifier stage with pairs of junction field effect transistors (JFETs), selected for their low noise and high gain. JFETs realize these advantages, in part due to their large size, but their size also introduces gain nonlinearity—that is, distortion. To compensate for these, bipolar junction transistors (BJTs) are added to the circuit. BJT bipolar transistors feature extremely low input impedance with very high output impedance, resulting in excellent bandwidth and linearity. By creating a cascode based on JFETs and BJTs, engineers were able to incorporate the best characteristics of both types of semiconductor devices into the circuit.

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They then connected the output of the cascode to another transistor of the opposite “polarity” (complementary). Current flows through it in the opposite direction, so that the direction of the signal current is “reversed”. This special circuitry is called a kink or broken cascode—and it is the hallmark component of Pure Path circuit design that provides high gain with low noise, wide dynamic range, and excellent linearity.

Specifications Mark Levinson No. 536

Output power 1 x 400 W (8 ohms, 20 Hz – 20 kHz, THD less than 0.3%), 1 x 800 W (4 ohms)
Minimum load impedance 2 ohms
Slew rate 100 V/µs
Frequency response 10 Hz – 20 kHz (+ 0/ – 0.2 dB)
Signal-to-noise ratio over 85 dB (2.83 V)
Input impedance 60 kΩ (XLR), 30 kΩ (RCA)
Voltage gain 26 dB
Ratio harmonics less than 0.02% (1 kHz)
Inputs balanced XLR, unbalanced RCA
Other switching interface RS-232 (RJ11), Ethernet port (LAN), USB port (designed for connecting a USB drive with software updates or for importing setup configurations) , MicroUSB port (designed to connect the device to a computer to access the internal web page), trigger connectors (input/output)
Speaker output 2 pairs of gold-plated screw terminals with Hurricane fixing screws
Power supply shielded toroidal transformer (1800 VA), 16 discrete fast-acting Schottky rectifier diodes TO-220 (40 A, 250 V), 36 electrolytic filter capacitors, which ultimately provides a capacity of 169200 μF
Transistors discrete bipolar output transistors TO-264, 24 pcs. (15 A, 260 V, 200 W), discrete bipolar transistors TO-220, 24 pcs. (230 V, 70 MHz, one for each output transistor)
Power Consumption 350 W (power on, no signal), 65 W (standby), 5 W (power-saving standby), less than 0.5 W ( eco-standby mode)
Dimensions (WxHxD) 438x197x533 mm
Weight 45.4 kg