Introduction; Front Panel; Controls; Indicators - Lyngdorf Audio SDA 2175 Owner's Manual

Introduction

Lyngdorf SDA 2175 is a compact, high-performance analog switch-mode amplifier utilizing
some of the circuit topologies originally developed for the Lyngdorf Millennium and M2150
amplifiers. Due to the switch-mode topology, with an efficiency of up to 85%, the SDA 2175
will provide its output power with minimal heat dissipation. A massive power supply with a
650VA toroidal transformer and more than 40000 microF capacitors ensures that the SDA
2175 can deliver the current to drive even the most demanding loudspeakers. The SDA 2175
has 2 gold-plated XLR connectors accepting balanced input signals and 2 gold-plated phono
connectors for unbalanced signals. The input signal is fed to the power amplifier circuit via an
AC-coupled true instrumentation type input amplifier. Except for the input amplifier, the SDA
2175 is fully DC coupled with no bypass capacitors or DC servos to degrade performance.
The protection circuitry in the SDA 2175 shuts down the unit in case of over-temperature, DC
voltage on the outputs and too high output current. The amplifier will resume normal operation
when the fault condition is no longer present. A trigger input and bypass on 3.5 mm minijack
connectors allow the SDA 2175´s standby mode to be controlled remotely.

Front panel

Fig 1: SDA 2175 front panel.

Controls

Mains switch
Turns the power to the unit on or off.

Indicators

OPERATE
Indicates the operational status of the SDA 2175.
Off The SDA 2175 is in standby mode (controlled via the TRIGGER input).
Flashing The SDA 2175 is in soft-start mode or the protection circuit is engaged.
On The SDA 2175 is operating normally.
POWER
Illuminates when power is applied to the SDA 2175 and the mains switch is ON.
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