Mark Levinson ML-6 (c. 1970s)

Name: Mark Levinson ML-6
Brand: Mark Levinson

The ML-6 was the first of Mark Levinson's ML-series preamps. Mark Levinson himself designed it along with Tom Colangelo, with John Curl also involved per some accounts. It set the template the company followed for decades: a two-chassis, dual-mono design with the amplifier module in one chassis and the power supply in a separate box, built to a standard that ignored cost.

The record on exact production years is thin, but the ML-6 dates from the mid-to-late 1970s. The ML-6A was the first iteration, followed by the ML-6B as the final revision. The ML-7 was later designed to hit a lower price point. The ML-6A used discrete, class-A single-ended circuitry throughout - no op-amps - and was line-only, with a phono stage available only as an option. Output was single-ended (RCA). It weighed roughly 25 kg per chassis.

Period reviewers were clear about it. J. Gordon Holt in Stereophile called it one of the very best-sounding preamps he'd tested at the time. He found it neutral, with no euphonic colorations, and the measurements verified flat response and low noise. Robert Harley in The Absolute Sound later described it as "the reference product of its time" and noted that newer preamps were still being compared against it years after its production ended. A Hifi-Writer retrospective more than 40 years on found the ML-6A still a viable high-end preamp, within 0.1 dB of flat from 10 Hz to 50 kHz on the bench, with gain of 20 dB. The ML-6's hand-built nature was noted in Audio (November 1980, p.116), which observed that all units were literally handmade.

Known specs, such as they are documented:

- **Configuration:** Two-chassis (amplifier module + separate power supply), dual-mono

- **Gain:** 20 dB

- **Inputs:** Line only (phono optional)

- **Output:** Single-ended (RCA)

- **Circuitry:** Discrete, class-A single-ended; no op-amps

- **Weight:** approx. 25 kg per chassis

- **Dimensions:** 50 × 15 × 43 cm per chassis (W × H × D)

Owners note a few aging issues. The volume potentiometer gets noisy and may need replacement, electrolytic capacitors benefit from replacement, and the class-A output stages eventually need re-biasing. The ML-6A has a balance control but no mono switch. The later ML-6B dropped the balance control. No original price is documented, but used units have changed hands recently in the $6,500-$7,200 range for serviced examples, and at least one fixer-upper went for €1,500.