Moerch Minuet

Digital audio signal sources have become more and more popular in the high end Hi-Fi market. The CD player, which appeared in the early eighties, has been followed by the DAT recorder, satellite radio, and recently by Mp3 players, the MiniDisc and DAB radio.

Digital audio has great advantages, but it does leave one particular sensitive spot: The conversion of the digital data to an equivalent analog signal must be done with ultimate precision, if the sound quality contained in the digital material is to be achieved.

The design of the Minuet

Fundamental to the Minuet is a sound mechanical construction: The circuitry is divided into modules, each module screened by a heavy aluminum frame. Thus the digital parts, known to be a potential source of noise, are kept completely separated from the analog parts. These in turn are divided into modules for each channel, Left and Right.
The modularity allows for easy future upgrading.

To further eliminate digital noise, the complex IC's in the digital module and the sensitive converter IC's in the analog modules, have all been wrapped in thick silver foil.
The Minuet comes in a single ended as well as in a truly balanced version.

Power Supply

The supply of power within the Minuet is done without compromise: Analog and digital supply are kept completely separate, right down to the mains line, which is filtered.
There are two levels of voltage regulation, with a total of 25 regulators (41 in the balanced version). Bypass capacitors are high quality polypropylene throughout the analog supply.

The Signal Path

The digital circuit uses an eight-times oversampling filter, which interpolates the 16-bit audio data with 20-bit precision.
The analog circuit is based on the new Burr-Brown PCM1702P converter IC, in the especially selected "K" version. This converter has 20-bit resolution, and is based on the technically superior Advanced Sign Magnitude architecture.

The analog signal path is DC coupled and it is kept as simple as possible using the best discrete components like high voltage polypropylene capacitors and special non-magnetic resistors. To ensure the necessary protection of amplifiers and speakers and to prevent the converter from influencing the working conditions of amplifiers and speakers a low pass filter is built around two Analog Devices AD845KN operational amplifiers.

The low pass filter is of the soft "Bessel" variety, which has a constant time delay up to and beyond 100 kHz. In combination with the digital oversampling filter this means that the phase response is virtually the same. as it would have been without filter.

The standard single-ended Minuet has one converter IC per channel. In the balanced version, the phase-splitting is done digitally, and there are two identical analog circuits for the positive and negative phase. Thus, the balanced Minuet uses four converter IC's totally.


The Minuet has a one-of-four input selector. The inputs are equivalent, and can be connected to any digital source: CD, DAT, DCC, MiniDisc, Mp3 players or digital radio. The converter switches automatically to the appropriate sampling rate. The chosen input input is copied to the digital output for recording purposes.
The standard Minuet uses high quality non-magnetic gold-plated BNC connectors for the digital signals, but other options are available: AT&T ST-type optical connectors offers the best possible optical link, while TOSLINK optical connectors, and RCA electrical connectors are compatible with a wide range of products, eliminating the use of special cables.
The use of BNC connectors however are recommended as to RCA connectors for the digital inputs.

The analog outputs are high quality RCA sockets from WBT for the single-ended version. The balanced version uses professional XLR sockets from Neutrik.
A phase inverter, working in the digital domain, is present as well. This is for adjusting the absolute phase. Whether this should be done depends on the recording.


Housed in an elegant slim-line case, with a black front, and round gold-plated buttons with red LED indicators, the Minuet goes very well with the Moerch tonearms, as well as most third party equipment. On special order, a luxurious all-gold front or chrome front is available.

Copyright © 2006 H.H. Moerch

Moerch DP-8/DP-6/UP-4 Patents: United States No. 4,257,615, United Kingdom No- GB 2 035 656 B