Harman’s Mark Levinson Introduces 523 Preamp Harman’s Mark Levinson has introduced its 523 preamplifier.RS Staff ⋅ May 16, 2016 Harman’s Mark Levinson has introduced its 523 preamplifier. With precision control including a discrete, balanced R-2R Ladder volume control, Class-A Phono stage, and Class-A Main Drive Headphone output, the 523 preamplifier delivers performance regardless of analog source. Six line-level analog and phono inputs travel through the Mark Levinson proprietary Pure Path discrete, direct-coupled, dual-monaural signal path in class A. Housed in a cold-rolled steel and 6000-series aluminum chassis, the 523 is designed and handcrafted in the USA. “The 523 preamplifier offers unprecedented levels of purity and precise performance,” said Jim Garrett, director of marketing and product management, Harman. “With every stage operating purely in class A, from Pure Phono and line inputs to the main drive headphone and line outputs, you’ll discover what you’ve been missing.” The basis of many volume controls is an analog potentiometer—a device with a number of performance drawbacks. Rather than attempting to improve upon this flawed design, Mark Levinson engineers abandoned it for a complex circuit architecture called an R-2R Ladder. In the R-2R Ladder, a string of resistors, all with identical resistance (R), form the side of the ladder, with another set of resistors forming the rungs, all identically with double the resistance (2R). An R-2R Ladder has no mechanical contacts to wear out. Because the 523’s R-2R Ladder uses low-value, precision resistors throughout and operates in current-output mode, the bandwidth and transient response of the volume control are remarkably consistent regardless of the volume setting. The 523 offers five line-level analog inputs: two balanced (XLR), and three single-ended (RCA) in addition to the Pure Phono (RCA with grounding pin) input. The preamplifier delivers its signal to balanced (XLR) and single-ended (RCA) stereo outputs, as well as a 1/4-inch (6.3mm) main drive headphone output integrated into the front panel metalwork—a first for Mark Levinson. A selectable, fourth-order, 80 Hz high-pass filter enables seamless integration of subwoofers for full-range performance. Newly developed for the 523 and 526 preamplifiers, the Mark Levinson Pure Phono stage features fully discrete, low noise gain stages, with RIAA equalization implemented using a combination of active and passive filter circuits. Four gain settings, multiple resistive and capacitive-loading settings, and an infrasonic filter are adjustable from the preamplifier’s front panel and remote control for powerfully optimizing performance for virtually any turntable and cartridge. System integration connectivity includes Ethernet/IP control, RS-232, USB for monitoring and configuration via web page, plus DC triggers and an IR input. The 523 preamplifier and its sibling 526 preamplifier with Precision Link DAC will be available from authorized Mark Levinson dealers worldwide in summer 2016.