Plinius M-15 Brochure

PLINIUS M15 LINE PREAMPLIFIER

Thank you for buying a Plinius product. This Preamplifier has been carefully designed
and manufactured by hand and under normal circumstances will maintain its present
high level of performance for many years to come. Please read this manual fully before
you attempt to use the Model 15 as it does require some familiarisation before you add
it to your music system.

Serial Number:

Date of Manufacture:

Final Test Certified by:

PLINIUS M15 Instruction Manual Page 1

INTRODUCTION

The Plinius Model 15 Preamplifier is a continuation of the design philosophy embodied
in all Plinius Amplifiers and involves the use of assymetrical circuit topology as
opposed to the more normal symmetrical approach. The Model 15 is a minimalist
design using recently designed circuitry based on the SA Series of Power Amplifiers.

The Model 15 uses an "on board" power supply which consists of a large value
toroidal transformer and a tightly regulated initial power supply system. The main
power supply occupies a large circuit board located along with the toroidal transformer
in a cabinet beneath the main circuit board and is isolated by an aluminium and Custom
Wood shelf. This shelf is a sandwich construction 10mm thick and provides a high
mass low resonance structure for the main circuit board.

The M15 Chassis is constructed in the main from 10mm aluminium with a 12mm
aluminium front fascia. We have designed the chassis to be as resonant free as possible
and this has great bearing on the 'sound' of the preamplifier.

CIRCUIT DESCRIPTION

The power supply consists of a low noise custom made toroidal transformer feeding a
conventional diode bridge and capacitor input filter. The output of this is taken by a set
of three terminal regulators which provide clean raw power for the main regulators.
The main regulators are separated into those for the left and right channels. These
regulators use a very sophisticated shunt system combined with a high impedance
source. This allows a large degree of rejection of power supply borne noise. The
output maintains a low impedance over a wide range of frequencies.
Remote sensing of both supply rails and grounds ensures that the stages are provided
with ideal conditions.

The Output section is an elegant balanced-bridge amplifier using a circuit topology
close to that of the Plinius SA series of amplifiers. This circuit provides both In and
Out of Phase signals to allow Phase switching and Balanced Output.

Every component used within the Model 15 has been chosen for sonic excellence and
all signal cable is by Siltech. All switching is done by coin quality silver contact
switches and the coupling capacitors are manufactured for Plinius by Hovland.

CONTROLS.

The volume control is an ALPS type and will accurately convey the source signals to
the high level amplification stages.

PLINIUS M15 Instruction Manual Page 2