2
Thank You from all of us at McIntosh
You have invested in a precision instrument that
will provide you with many years of enjoyment.
Please take a few moments to familiarize yourself
with the features and instructions to get the
maximum performance from your equipment.
If you need further technical assistance, please
contact your dealer who may be more familiar with
your particular setup including other brands. You
can also contact McIntosh with additional questions
or in the unlikely event of needing service.
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, New York 13903
Technical Assistance
(607) 723-3512
Fax (607) 724-0549
Customer Service
(607) 723-3515
Fax (607) 723-1917
Website
www.mcintoshlabs.com
Please Take A Moment
For future reference, you can write down your serial
number and purchase information here. We can
identify your purchase from this information if the
occasion should arise:
Serial Number:
______________________________
Purchase Date:
______________________________
Dealer Name:
______________________________
Copyright © 2021 by McIntosh Laboratory, Inc.
Table of Contents
Safety Instructions. .. .. .. .. .. .. .. .. .. .. Separate Sheet
Important Additional
Operation Information Guide
General Information . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 2
Connector .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 3
Introduction .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 3
Performance Features .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 3
Installation . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 4
Installation of Side Rack Mount Brackets . .. .. .. .. .. 4
Dimensions .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 5
Audio Input for Each Amplifier Channel .. .. .. .. .. .. 6
Making All the Right Connections .. .. .. .. .. .. .. .. .. 7
Output Plug Connection.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 8
Connect From a Multichannel Zone Preamp . .. .. .. 8
How to Operate .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 9
Front and Rear Panel Displays. .. .. .. .. .. .. .. .. .. .. . 10
Specifications .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 11
Packing Instructions . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . 11
General Information
1. For additional connection information, refer to the
owner’s manual(s) for any component(s) connected
to the MI1250.
2. The MI1250 mutes the speaker output for approxi-
mately two seconds when first turned on.
3. Included with the MI1250 and located in the
Owner’s Manual Packet are two Side Rack Mount
Brackets and screw fasteners. Refer to page 4 for
installing the Side Rack Mount Brackets.
4. For the best performance and safety it is impor-
tant to always attach a single Loudspeaker with
Important Safety Information is supplied in a separate document “Important Additional Operation Information Guide
”
an 8 Ohm or 4 Ohm impedance to the Channel
1 - Channel 8 output terminals. Refer to “How to
Connect” pages 8 thru 10.
Note:
The impedance of a Loudspeaker actu-
ally varies as the Loudspeaker reproduces
different frequencies. As a result, the nomi-
nal impedance rating of the Loudspeaker
(usually measured at a midrange frequency)
might not always agree with the impedance
of the Loudspeaker at low frequencies where
the greatest amount of power is required.
Contact the Loudspeaker Manufacturer for
additional information about the actual im-
pedance of the Loudspeaker before connect-
ing it to the McIntosh MI1250.
5. In the event the MI1250 Channels overheat, due
to improper ventilation or Loudspeaker Imped-
ance, the protection circuits will activate. The Front
Panel Channel LED will change color and the au-
dio will be muted. Refer to page 10. When the unit
has returned to a safe operating temperature, the
Channel(s) normal operation will resume.
6. If it becomes necessary to replace the Loudspeaker
Connection Plugs used on the MI1250 Rear Panel,
order part number 31065800 from the McIntosh
Parts Department.
7. For additional information on the MI1250 and
other McIntosh Products please visit the McIntosh
website at www.mcintoshlabs.com.
