NAD Masters Series M3 User Manual

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and mono settings. Tone controls offer bass and treble

adjustment, as well as a ‘spectral tilt’ option that is highly

effective at correcting the tonal balance of many recordings

by simultaneously increasing the bass and decreasing the

treble (and vice versa) to create a warmer (or cooler) balance.

We have also included a second set of preamp outputs

and a switchable high pass ﬁ lter for the internal ampliﬁ er,

to allow easy implementation of an active subwoofer or

biampliﬁ cation.

The rugged chassis is built using thick 2mm mild steel

plates with a front panel employing extruded aluminum

and die-cast zinc in its construction. Special attention

was paid to the control of mechanical resonance, as this

can affect sonic performance. Special isolation feet use

aluminum and silicon rubber in a vibration damping

conﬁ guration. All signal connectors are heavy duty gold

plated types speciﬁ cally engineered for the NAD Masters

Series components. Finished inside and out, the M3 utilizes

powder coating and advanced automotive paint ﬁ nishes,

creating an enduring and elegant mechanical package.

PREAMP DESIGN

The preamp uses all discrete low noise high impedance J-

FET buffer amps and very high quality reed relay switches

at the preamp input. Special high current low output

impedance Class A gain modules provide tremendous

dynamic headroom and high output current, combined with

a exceptional S/N ratio in excess of -100dB (IHF).

The volume attenuator is very unique in that it uses discrete

1% precision resistors that keep impedance (and noise) very

low. It is arrayed in 3 stages to reduce the residual noise in

each amplifying stage and prevent the ‘cascade effect’ of

noise that is present in most preamp designs. This circuit

also provides the balance control, and as a result channel

separation is superb and inter-channel cross talk is virtually

eliminated. These resistor arrays are switched using 15

volt digital switches under software control, keeping all

attenuation at the ideal point in the circuit architecture.

Low impedance stepped tone controls provide +/- 5 db

of boost/cut in the bass and treble regions, or can be

conﬁ gured to provide variable slope, or ‘spectrum tilt’ at +/-

3dB per decade.

Biamp function allows the use of a second ampliﬁ er or

active subwoofer PreOut 2, and offers a high pass ﬁ lter

function on PreOut 1, with selectable 40Hz, 60Hz, 80Hz,

100Hz or Full Range options. These are analog 2nd order

ﬁ lters conﬁ gured around the low impedance differential

Class A output stage of the preamp. This output stage also

employs proprietary distortion cancellation circuitry.

A balanced line input is also provided using identical JFET

buffers feeding a discrete differential amp and yielding

common mode rejection in excess of 80dB.

Separately regulated DC supplies are derived from the

dual mono power supply. Copper buss bars and discrete

regulators keep circuit noise to an absolute minimum

throughout. The display and digital functions operate from

an independent power supply to prevent any interference

with the analog signal path.

POWER AMP HIGHLIGHTS

The M3 features a Dual Mono design with separate

unregulated, and discrete regulated supplies for different

stages of the 2 channels. The twin custom-made “Holmgren”

toroidal transformers use proprietary magnetic shielding

technology. High current rectiﬁ ers feed low ESR 105C ﬁ lter

capacitors.

NAD’s PowerDrive technology measures load impedance

continuously on each channel and adjusts the power supply

voltage for maximum undistorted dynamic power into the

connected speaker at all times and under all operating

conditions. The signal processor also continuously

measures temperature and average long term power and,

based on this information, chooses the optimum voltage.

PowerDrive allows the M3 to sound far more powerful than

its already impressive 180 watt per channel rating would

suggest. Totally effortless sound, even at elevated levels, is

the hallmark of the PowerDrive ampliﬁ er.

The M3 utilizes a wideband current-mode Class A voltage

amp featuring large open loop compensated bandwidth,

and running from low noise stabilised power supplies.

NAD’s patented current amp output stage starts with < 0.02

% static and dynamic distortion open loop (before feedback),

even into 3 ohms at 20-20k at all levels. By utilizing small

amounts of feedback the circuit returns distortion levels

at all audible frequencies that are at limit of measurement

– less than 0.002%!

The super rugged output stage features 4 pairs of 150W

discrete bipolar output transistors per channel, for 50A peak

undistorted output current. Massive heat sinking assures a

lifetime of trouble free operation.