Mclntosh Laboratory, Inc. 2 Chambers Street, Binghamton, New York 13903 Printed

CONTENTSPerformance Specifications 3Notes 3Rear Panel 4Front Panel and Trim Parts List 4Section Locations 5-6Block Diagram 5-6Interconnection Diagram 6-9Input/Output (Left and Right) 10-12

Amplifier 11-14Control and Balance Control 14-18Treble 19Bass 20Speaker Switch 21AC Power Supply 22DC Power Supply 23Repacking Instructions 24

Performance Specifications

FREQUENCY RESPONSE+ 0, -0.5dB from 20Hz to 20,000Hz

RATED OUTPUT2.5V at MAIN and SWITCHED 1 and 2, andBALANCED OUTPUTS

MAXIMUM VOLTAGE OUTPUTMore than 8V at all outputs

TOTAL HARMONIC DISTORTION0.002% maximum IHF, 0.2% maximum from 20Hzto 20,000Hz at rated output

SENSITIVITYPhono: 2.2mV for 2.5V rated output, (0.45mV IHF)High Level: 250mV for 2.5V rated output, (50mVIHF)

SIGNAL-TO-NOISE RATIO, A-WEIGHTEDPhono: 80dB below 10mV inputHigh Level: 90dB below rated output

VOLTAGE GAINPhono To Tape: 41 dB at 1000HzPhono To Main: 61 dB at 1000HzHigh Level To Tape: 0dBHigh Level To Main: 20dB

INPUT IMPEDANCEPhono: 47K ohms and 65pF CapacitanceHigh Level: 22K ohms

TONE CONTROLSBass and Treble stepped, 20dB boost to 20dB cut

AC POWER OUTLETS4 switched and 1 unswitched, Total capacity 1400watts

POWER REQUIREMENTS120V, 50/60Hz, 37 watts

DIMENSIONSFront Panel: 16 inches (40.6cm) wide by 5-7/16inches (13.8cm) high. Chassis depth behind mount-ing panel, including clearance for connectors: 14inches (35.6cm). Knob clearance required in front ofmounting panel: 1-1/2 inches (3.8cm).

FINISHAnodized gold and black front panel, chassis is black.

WEIGHT16 pounds (7.3Kg) net, 25 pounds (11.4Kg) inshipping carton

Notes

1. The four types of heavy lines on the schematicsdenote the primary signal path in the followingmanner:

= LEFT CHANNEL= RIGHT CHANNEL= LEFT BALANCED= RIGHT BALANCED

2. Unless otherwise noted, all voltages indicated onthe schematics are measured under the followingconditions:a. AC input at 120 volts, 50/60Hz.b. All voltages are ±10% with respect to

ground. A high impedance (10 megohm)voltmeter must be used.

3. Unless otherwise specified:a. Resistor values are in ohms.b. Capacitor values are in microfarads (uF).

4. The voltages enclosed in a box are signal voltagesthat are measured with a 2.2mV, 1kHz signalconnected to both channels at the PHONO 1INPUT JACKS.

FRONT PANEL CONTROLS are set at:BALANCE CENTER DETENTBASS and TREBLE CENTER DETENTINPUT SELECTOR PHONO 1LOUDNESS NORMALMODE STEREOPOWER ONVOLUME CLOCKWISETAPE MONITOR 1 and 2 NORMALRUMBLE and HF FILTERS FLATSPEAKERS 1&2

5. On PC Board Drawings, Square Pad Indicates:a. Polarized Capacitors - Positiveb. Diode - Cathodec. Others - Pin 1

6. WARNING:Parts marked with the symbol have criticalcharacteristics. Use ONLY replacement partsrecommended by the manufacturer.

3

Rear Panel

Fig. 1 Rear view

FRONT PANEL and TRIMPARTS LIST

Symbol

016340016334018511018512018520018521C22-FrontPanel090242090243090244101035104143104144

Description

Indicator GlassFront Panel GlassTop Panel ExtrusionLower Panel ExtrusionEnd Cap LeftEnd Cap RightFront Panel Complete W/GlassInput/Mode KnobBalance/Volume KnobBass/Speaker/Treble KnobScrew, 4-40 x 5/16 Fill HeadFelt Washer 3/4" DiaFelt Washer 5/8" Dia

4

5 6

Block Diagram

Section Locations

INTERCONNECTIONPARTS LIST

Symbol Part Description

CAPACITORSC1.C2 061276 DISC CAP, .0047uF,

400VAC

JACKSJ2,J3 117563 Phone JackJ4,J5 117437 XLR Connector, Male

LIGHTING DEVICESDS1.DS2 058138 Lamp Fuse StyleDS3.DS4 058137 Lamp Disc Indicator

SWITCHESS1-S6 148068 Slide Switch (SPDT)

TRANSFORMERST1 159248 Power Transformer

Interconnection Diagram

7 8 9

Input/Output, Left and Right

AMPLIFIER PCB 048474

1210 11

LEFT INPUTS/OUTPUTS PCB 048481AND

RIGHT INPUTS/OUTPUTS PCB 048476 AMPLIFIERPARTS LIST

Symbol Part

RELAYSK1-K4 087056

DIODESD1.D2 070102

TRANSISTORSQ1 132248

INPUT/OUTPUTPARTS LIST

Symbol Part Description

RELAYSK1,K7,K9, 087056 Form 1C, 5VDC, Reed,K11,K12 HE3321C0500

K2-K6.K8, 087050 SPST. 5VDC, Reed,K10,K13-K16 HE3321A0400

Description

Form 1C, 5VDC, Reed,HE3321C0500

Zener: 51V, 5%, 400mW

NPN, 300V, 2SC3790D or E

NOTE: Components and valuestoned in gray warrant yourattention; parenthesized valuesapply to serial numbersL K 1 0 0 1 - L K 1 9 8 9 . non-parenthasized values apply toserial numbers LK1990 andabove.

Amplifier

1413

Control and Balance Control

15 16

Control and Balance Control

BALANCE CONTROLPCB 048478

CONTROL PCB 048479

BALANCE CONTROLPARTS LIST

Symbol Part Description

RESISTORS and POTENTIOMETERSR1 134475 Balance Control

CONTROLPARTS LIST

Symbol Part Description

DIODESD1-D32 070047 SIG, 75V, 150mA, 1N4148

INTEGRATED CIRCUITSIC1 133189 Dual Op-Amp. MC33178PIC2 133108 5V Regulator MC7805CT

RELAYSK1-K3 087050 SPST, 5VDC, Reed,

HE3321A0400

RESISTORSR1 134476 Volume Control

SWITCHESS1 146238 Input SwitchS2 146239 Mode Switch

TRANSISTORSQ1,Q2 132224 PNP, MPS4126

17 18

Treble Bass

BASSPARTS LIST

Symbol Part Description

SWITCHESS1.S2 146240 Bass/Treble Switch

TREBLEPARTS LIST

Symbol Part Description

SWITCHESS4.S5 146240 Bass/Treble Switch

BASS PORTION OFPCB 0484772019

TREBLE PORTION OF

PCB 048477

21

SPEAKER SWITCHPORTION OF

PCB 048477

SPEAKER SWITCHPARTS LIST

Symbol Part Description

DIODESD1-D6 070047 SIG DIODE 1N4148

SWITCHESS3 146241 Speaker Switch

Speaker Switch

WARNING: Parts located in the belowshaded area have critical characteristics.Use ONLY replacement parts recommendedby the manufacturer.

AC POWER SUPPLYPORTION OF PCB 048471

AC POWER SUPPLYPARTS LIST

Symbol Part Description

CAPACITORC9 061276 Disc Cap, .0047uF, 400VAC

FUSESF1 089081 Fuse 1A, 2AG

RELAYSK1 087054 SPST,12VDC

22

DC Power Supply

NOTE: Components and valuestoned in gray warrant yourattention; parenthasized valuesapply to serial numbersL K 1 0 0 1 - L K 1 9 8 9 , non-parenthasized values apply toserial numbers LK1990 andabove.

WARNING: Parts located in the belowshaded area have critical characteristics.Use ONLY replacement parts recommendedby the manufacturer.

DC POWER SUPPLYPARTS LIST

Symbol Part Description

DIODESD1.D2 070044 BRIDGE, 400V, 2A

23DC POWER SUPPLY

PORTION OF PCB 048471

Repacking Instructions

In the event it is necessary to repack theunit for shipment, the unit must be packed exactly asshown below.

IMPORTANT - The four plastic feet mustbe attached to the bottom of the unit so they willlocate in the four holes of the bottom pad. Failure todo this will result in shipping damage.

If a shipping carton or any of the interiorparts is needed, please call or write the CustomerService Department of Mclntosh Laboratory. Orderparts from the accompanying list by part number.

Use the original shipping carton and interiorparts only if they are in good serviceable condition.

Qty.

12

111

444

1

Part No. Description

033870 Shipping carton only033884 Corner pad

033883 Inside carton only033885 Top pad033886 Bottom pad

017156 Plastic foot100160 #10-32 x 9/16" Screw104080 #10 Flat washer

033915 Shipping carton completewith all the above parts

INSIDECARTON

BOTTOM PAD

10-32x9/16"SCREW WITHWASHER (4)

BOTTOM COVER

UNIT WITH(4) FEET ON

TOP PADINSIDECARTON

CORNERPAD

SHIPPINGCARTON

C22 PREAMPLIFIER

Part No. 040354BE032003

Printed in U.S.A.Mclntosh Laboratory, Inc., 2 Chambers Street, Binghamton, NY 139O3Telephone (607) 723-3512