Madrigal Audio 23.5 User Manual

1
Unpacking and placement
Unpack your Nº23.5 amplifier and keep all packing materials for future
transport. Because of the weight of the unit, handles are provided
front and rear so that two people may lift and carry the amplifier
comfortably and without risk of injury.
Carefully inspect your Nº23.5. If you find any damage or flaws, see
your Mark Levinson dealer immediately.
To keep speaker cables as short as possible, locate the Nº23.5 as close
to the loudspeakers as practical.
The Nº23.5 should be located at least three feet away from the
turntable and preamplifier. Otherwise, the Nº23.5 may induce hum into
these sensitive components.
The Nº23.5 may be placed in a cabinet or on a shelf, but adequate
ventilation must be provided to prevent overheating. The clearance
provided by the unit's feet must be maintained to allow unrestricted air
flow across the heat sinks and through the vents in the bottom of the
chassis (placing the Nº23.5 on thick carpeting, for example, may
reduce or eliminate the clearance provided by the feet). Clearance
above the unit must also be maintained to allow air circulation and to
prevent heat buildup.
The Nº23.5 incorporates thermal sensors located near each group of
output devices. If heat-sink temperature becomes excessive, these
sensors will shut off the amplifier before damage results. After a brief
cooling period, the amplifier can be reactivated via the switch on the
front panel. If this occurs regularly during normal use, it indicates that
the ventilation provided for the amplifier is inadequate. If there's
adequate ventilation and the problem continues, see your Mark
Levinson dealer immediately.
For custom installations and cabinetry, this information may be useful:
■ All temperature measurements are made at the top of the heat
sink, 3.5" behind the front plate.
■ Normal heat-sink temperature at idle after warm-up, with
unrestricted airflow at 22°C (72°F) ambient temperature: 36.5°C
(97.7°F).
■ Maximum permissible heat-sink temperature before thermal
protection is activated: 80°C (176°F).
For exact dimensions, see "Dimensions."
For your protection, review "Important safety instructions" before
you install your Nº23.5.
Unpacking
Placement
Ventilation
Custom installations
PRECAUTION

Madrigal Audio 23.5 Specifications

General

Brand	Madrigal Audio
Model	23.5
Category	Amplifier
Language	English

Summary

Unpacking and placement

Unpacking

Instructions for unpacking the amplifier and using handles for safe lifting.

Placement

Guidance on positioning the amplifier near speakers and away from sensitive audio components to prevent hum.

Ventilation

Details on ensuring adequate airflow around the unit to prevent overheating and activate thermal protection.

Custom installations

Information relevant for custom installations and cabinetry, including temperature measurements.

Voltage selection

Voltage selection

Ensuring the amplifier is set to the correct AC operating voltage for your location.

AC mains fuses

Information about the type and rating of fuses used in the amplifier and replacement precautions.

Signal connections

Connectors

Description of RCA-type and XLR-type connectors for audio signal input on the amplifier.

Cables

Recommendation for specific interconnect cables for connecting the amplifier to a preamplifier.

Connection methods and operating modes

Overview of operating modes: single-ended/balanced and normal/inverting.

Single-ended normal (non-inverting) operation

Instructions for connecting the preamplifier to the amplifier's RCA inputs for normal operation.

Single-ended inverting operation

Single-ended inverting operation

Guide for inverting operation using XLR inputs to achieve absolute phase at the loudspeaker.

Balanced normal (non-inverting) operation

Balanced normal (non-inverting) operation

Instructions for connecting the preamplifier's balanced outputs to the amplifier's XLR inputs.

Speaker connections

Output connection precautions

Warnings against connecting outputs to non-loudspeaker devices, short-circuiting, or cross-connecting channels.

Lug connection

Recommended methods for connecting speaker cables using spade or hook lugs.

Pigtail connection

Detailed procedure for preparing and connecting speaker cables using a pigtail method.

Connecting the speakers

Connecting the speakers

Step-by-step guide for connecting speaker cables to the amplifier and loudspeakers for each channel.

Power connection

Connecting the AC power cord

Instructions for connecting the AC power cord to the amplifier and the mains outlet.

Performance tips

Advice on initial warm-up time and optimal performance after extended use.

Protection circuitry

Explanation of the amplifier's protection circuitry and how to reset it after activation.

Bridged operation

Balanced bridged operation

Instructions for balanced bridged operation, requiring a special three-ended cable.

Single-ended bridged operation

Single-ended bridged operation

Steps for single-ended bridged operation using XLR-type input connectors.

Single-ended bridging cable

Single-ended bridging cable

Guidance on fabricating or obtaining a single-ended bridging cable.

Care and maintenance

Cleaning

Recommendations for cleaning the amplifier cabinet and connections.

Fuses

Information on fuse types and the importance of removing AC power before replacement.

Specifications

Technical Specifications

Detailed technical specifications for the amplifier, including power, frequency response, and dimensions.

Dimensions

Physical Dimensions

Diagrams and measurements for the amplifier's top and side views.