Melntosh C32 PREAMPLIFIER SERVICE INFORMATION STARTING WITH SERIAL NG. AY1001 McINTOSH LABORATORY ‘NC. BINGHAMTON, NEW YORK 13903 039-075132 PERFORMANCE LIMITS FREQUENCY RESPONSE 40 to =.5d8 From 20H2 to 20,000H2 Equalizer Out: #0 to -148 from 10Hz to 00, 000%2 DistorTioN. 05% maximum at rated output level, 20H2 to 200007 INPUT SENSITIVITY AND IMPEDANCE Phono 16 2: 2 millivolts at 47k 65pF Buxiliary: Tuner, tape 1, tape 26 tape 3 250° mil ivoits ot SOKt HUM AND NOISE Buxiliery, Tuner, tape !, tape 2 and tase 3- THF” io0é8;" Gnweighees' =30¢8, Phono | & 2: INF 908; unweighted 8008 below 10 millivole input or eduivelent to less than I microvolt at the input terminals. OUTPUT LEVEL AND IMPEDANCE Main Output: 2.5 volts with rated input to operate into 5,000 ohm or greater, load, Output source impedance 220 ohms Tope Output: 250 millivoles with cated input Fo_gperece into 5,000 ohns\or greater Monitor, Headphone, Line Output: 12 watts per Channel gone iauous Inco Bae less than’ siz tocal harmonic distortion 20k to 20,000Hz or 5 volts RMS Into 600% line Tevel controls proviced. PROGRAM EQUALIZER 1208 of boost or cut at 30, 150, 500, 1500 and 10, 00H2 VOLTAGE AMPLIFICATION In Decibels with all equalizers and filters input ___nwin_1T383 Mar Messetone gy howsTuer 204808 —<30d8 stan ots? aon ous 3008 eas tone 1 ads tad ess oro 2 62dp Sze TReB = T68 SEMICONDUCTOR COMPLEMENT 67 Transistors 35 Integrated circuits 62 diodes 2 Field Effect Transistors 1 Silicon controtes Rectifier (SCR) POWER REQUIREMENT 120 volts, 50/60H2, 25 to 85 watts MECHANICAL INFORMATION Size: Front, panel measures 16 inches wide {k0.64"'cm) by 51/16 inches deep (13'81 em). chassis measures 15. Inches wide. (38-1 en) by 5. inches high (12-7 em) By 13 inches deep (33.02 cm). Including PANLOG Shelf and back panel connectors. Knob clearance required is 1-1/2, Inches (SaiSem) in front of the mounting panel. Finish: Front panel is anodized gold and black with" Special gold/teal nomenclature TMlun- ination. Chassis is black: Hounting: Exclusive McIntosh developed profes sTénai paNLoc Weight: 26 pounds (11.8 kg) net, 36 pounds Ci7'2 ko)"in shipping carton. Shipping Carton Size: 21" x 21" x 11"TAPE 3 IN SAIN 4248 FEEDBACK Puono 1 O——+4 PHONO 2 Q——4 FET ANALOG. PHONO wire RIAA EQUALIZATION GAIN 0d rer ANALos RECORD BUSS wir FEEDBACK econo MONITOR swirce AC UNE TAPE 2.1% TAPE INO switen + fer i SUNAING FHONO our | at sreaxes |! OP ANE ounets | | cetee HOS) | conrsot |! SwiTeHes ! wm |! t ! Pro wanuag : ff 4 GAIN 048 ‘STH 2 7 rire 26 18¥ Auto Leone surety] Lrower sure. rum ox |} rower FEEDBACK cagcurt & [*}veansrormer ama RELAY Saal ea t owen surety Lower suercy] ee | I ~ switch tev aay suttls ‘OF ANE TUNER O- ux. PHOND 1 -—J PHONO 1 O—4 FET ANALOG PHONO. STH, PHONO, PREAMP ANALOG USTEN move swmrcH FEEDBACK RIAA EQUALIZATION GAIN 4248 RECORD MONITOR SWITCH ies SUMMING OF ANP FEEDBACK GAIN 046FEEDBACK ‘GAIN 1048 FEEDBACK ‘GAIN 1048 onmToP wonttor |_| monitor + sion iver Nene Lo} ae UE, or ae Suir ‘conTrot A 4 GAN 1888 am ode AW dt TARIRBLE PROGR TW 10W FLTeR Goalie tole oe One eae suree aunt weacting |} wonftever couauren cuntcer | wouMe nel OP AMP suit convo. I I i I seve \ aun swan | conrRoL ' I I ' \ sure couautes foe ae as oh volume Oe aM OF AMP Switch conto TaRABTE FICE melon nines Tatas nee FEEDBACK FEEDBACK GAN 180 Ga 048 GAN db “4 MonrToR montToR mote my OP AME, GAIN 1048, Trecvpace } FEEDBAC BACK MontTOR AMP INPUT Jo} AMP LEVEL ‘saiTcH CONTROL GAIN 1048 FEEDBACKC32 [0 tare 1 our are *) inteRtocks [-——O TAPE 20uT O Tare 3 0UT GAIN 248 FEEDBACK exoanoee ourur osmcieo SwiteHes FO SMITCHED GAIN 048 wen, qT ON I @ LOW FILTER FEEDBACK EXPANDER DELAY 1 O main OUT L0G AMP AND ayrass. UNE EQUALIZER maTCHING }-——ONe out DEFEAT EXPANDER NETWORK T MONITOR L ‘SWITCH ee MATCHING -———© LINE OUT ‘HI & LOW FILTER) LOG AMP: DELAY MAIN OUT GAIN OdB lee |___g swurcueo outer wc SPEAKER SHECHES. [-——O SITEHED EXPANDER BYPASS FEEDBACK GAIN 248 = mre 3 our 7 O TAPE 2 OUT wntetocas [>———O Tare 1 ouT BLOCK DIAGRAMPower suppuy ‘048-120 wt INTERCONNECT32 LEFT meyr smcronme eran IGHT INEUT SWITCHING 00 Se SBS, we RECORD SWITCH ‘048-380 LISTEN MoD, SWITCH ‘O45 117 ve32 EXPANDER et 10 SEE Bh nes ur anf S HEADPHONES : : : i pore "SB SEE! 5 EE Forme 5 see dias E fg Pr oe anaaadaad owe cre Tie momo tee PEPELEEPEE ae. 085122 I cana Hieee hy Yn BEE IB ewes po ofbae 3 oe PUSH eupaugmren hi et : £ Fye ede [ seer ar 230 a EH Of. gty bed a ek 4 Load cgesdeediiie! Gilee:z ai <8 3 Reg S225 sb ee ses FEE ESE gy mmr ommanfey a aaa? citidds B TTTy Ta a* Oy 2 C ay TONE FuLTER nn stmt soo Sean's d 9. oSCHEMATIC NOTES oe Unless ovvervise specified: Resistance values are in ohs, 1/4 yatt, and 5% tolerance eapset Sts woluek sual ise: enn’ sre’ fo'microrarads” (Or) capeel cance’ valess grecter’ than 1 sre"Gntgleorarade (pE3: snasetors gre in microhenries an). Funbsrs ground the dotted fines, correspond to the hurbers’ an the PC Bosrd layouts, we 1"! Petia cee tee ee eel The terminal nunbering of rotary switches is for reference only. All voltages indicated on the schenatles ore measured under the folloring condi tions 8. Use of an 11 megohm input impedance VIVK b. All voltages + 10g wieh respect to chessis ground. e+ We signet at input terminals €. AG Input ot 120 voles, 50/40 We. ©. Front pane! controls at: Listen Aux ( Record oe ode Selector stereo Equelizer Free cencer detent Volume cow Exponder orf batence enter detent Loudness Flas bush Switches out ower switch on AIl other controls at normel positions. 4 Ja units with Serial Ho's below AY2076 0200, 0201, 0202, ¢ 9203 are used i In units with Serial Ho's below AY1295 R943 and ROW ore not used. In units with Serial wo's below AY3O00 RBI3, RBI4, A621 ond 8622 are S600 unk wish Seria! No below £13000: CD and CESD ore .005HF, C&S, 6632, C633 ond e638 Lunds wish serial No « below A¥2000; A508, A510, RSIS an A514 ore Gi 4307 ond SOE Io units with Serta! Ho's below AY2076: 9301, 0302, 0303, 6301, £382, and C303 are not sed j In units with Serial No's Below AY3000: R310, R3IT and R312 are not used. eo In units with Serial No’s below AY2289 C4002 is not used. {5 with Serig] No's below AY3000: R913 and RBI4 are 15K; R925 and R926 are 3300; C911 ‘ee W7uFs COIS and C916 are 220uF and R927 and A928 are used.eT Hite 2, LEFT INPUT SWITCHING 045-149LEFT INPUT SWITCHING. ‘eas i89) LEFT INPUT SWITCHINGRIGHT INPUT SWITCHING€ a aay, “teTone FuLteR ‘Oas 008 TONE FILTERC32 C32 HEADPHONE AMP.HEADPHONE AMP (048-272é ik vO T ioe | 2 Mi EE cml ae { UL Foe © Edd | © eee 2(32 a O on om GQ a i fs (asa = “om ae Chews Opfent ‘ar Sar = EXPANDER PC BOARD 045031 ae ”PUSHBUTTON SWITCH a.o)T PUSH BUTTON SWITCH PC BO, 045-090 ee aa 1 iM 11 ai rai 41 a EF) 11 ¥1 ¥1 [SayEXPANDER /BALANCE/LOUDNESS eae ere aeEXPANDER, BALANCE & LOUDNESS PC BOARD 045-169 32| | | | | | | | | | | | | 44 LISTEN /MODE SWITCHLISTEN-MODE SWITCH PC BOARD 045-117AUTO TURN ON RECORD SWITCH 32Te “hy Be | ae Og B.@ at Ea fl@lges AUTO-ON PC BOARD 7 045-121 RECORD SWITCH PC BOARD 045-33032 Twoicaror oaectTs I I I | | 1 | 1 i ! i i Lo INDICATOR POWER SUPPLY (045-120 Ss UT OOCOmmnny le CCC] —-— POWER SUPPLYSWITCHED OUTPUTLEFT SWITCH OUTPUT PC BOARD 045-122 = el 4 = ounat ovtewr# ae RIGHT SWITCH OUTPUT PC BOARD 045-123,REPLACEMENT PARTS sto SSL PR AIEEE an Ierlacengigenren te stoned en oreed tas Fee etn rome {Selene eS SII ci. Number Description Number 204, 205 or Bridge 070-044 9206, 207 ova. at2 tener tw encom ank.27 228,229 Zener V2v 070-099 232,233 ou.) tener I ero ah ou. 31 snl lat oroky—— au67 Oe 285 si. sign diode creat) 0.202 0816227 51. sign diode oroaky ov8.439 shit a crosoy ae ose, 30 6.2 Togas. 68 vos tar 2 opoaes to. ows te av o7mons ta vied seer sav epoots s.r O10 102 cross a. 91081006 ome cron) a5. 56 2105106 cress 2107188 ed top crowns aonsio D100) Ae top crowns gral wn Bridge Rectifier Si, Rectifier s ser = Rectifier TRANSISTORS NPN St NPN si PNP Si NON Ss NON Si PNP si NPN Si Transistor Transistor Transistor Transistor Transistor Transistor Transistor Junction FET NN si NON St NN si NPN Si NPN Si NON Si NPN Si NON Si NN Si NON Si NON Si NPN St NON st st NPN st NPN St NPN si NPN Si NPN Si PNP si PNP st PNP Si NPN st PNP si PNP si PNP Si NPN si NPN NPN Power Transistor PHP Power Transistor Si pNP Transistor Transistor Transistor Transistor Tran Tran stor Transistor Transistor Transistor Transistor Transistor Transistor Transistor Darlington Dartington arlington Dartington Darlington Darlington Darlington Transistor Transistor Transistor Transistor Transistor Dartington Transistor Darlington 32 070-044 070-031 070-059 131-008 132-093 132-093 132-096 132-096 132-098 132-096 132-034 132-170 132-093 132-093 132-093 132-098 132-093 132-093 132-093 132-093 132-093 132-093 132-098 132-093 132-093 132-090 132-090 132-00 132-00 132-090 132-182 132-182 132-096 132-093 132-096 132-056 132-056 132-030 132-149 132-167 132-166 132-182INTEGRATED CIRCUITS e101 Regulator + 18y 133-045, tcioz Regulator - 18v 133-044 1€200,201 Integrated circuit 133-082 1€202,203 Integrated circuit 133-042 1C204,205 Integrated circuit 133-051 1€206,207 Integrated Circuie- > 33-043 1¢208,209 Integrated Circuit 133-051 16210,211 integrated cireuie 133-043 1c501,502 Integrated cireuie 133-066 e601 602 Integrated cireuie 133-043 16603, 604: Integrated Circuit ++, 1133-003 1cBd17802= * Frtegrated- circu 2 133,068 1e803,804 Integrated Circuit” ~ “133-068 1¢805,808 Integrated circuit 1¢807,808° * Tntegrated circu 1¢809,810 Integrated circuit 1C811,812 Integrated circuit 1ea13 Integrated Circuit 1c901,902 Integrated circuit ‘CABRCITORS, 3.4 Elect 4700uF 30v KI Relay SPst 087-020 201,202 heed Reley 087-023 203,204 eed Relay 087-023 205,206 Reed Relay 087-023 801, 092-. - Raed Redoy ao 087-088 901 feed Relay 087-029 > St oven yon fend net Re “olune control 13h-305 85017 Sbatdnce/Loudséss wisi ‘R502 Expand 134-313 R601,602 . Equdlizer Frec + 136-316 603,604 Equalizer Freq. 34.316 R605. afgualizer Frege ge ..2 3h-316 8909,910 Right/tert Goin 134-306 R9h7 Level hatch 134-306 capaci ons C34 Elect 4700uF 300 066-276 039-075 066-276 3301 shot shor $501 s701 SwiTeHes Record Switch 146-187 Listen switch 146-187 Mode Selector 146-186 Bypass Switch 134-310 Pushbutton Switch 150-024 FUSES Fuse 1A Norm Blo 089-002 TRANSFORMERS Power Transformer 5-342 Lawes Front Pane! #634 058-043 FRONT PANEL 6 TRIM Front Pane! Glass 016-153 End caps 018-160 Knob Listen 090-156 Knob-Record 090-156 knob -Hode 090-159 knob -volune 030-170 knob-£q, Frequency 090-171 Knob -Expander 090-171 Knob-Balance 090-187 Knob-Loudness 090-186 MISCELLANEOUS Shipping carton 045-321 Mounting Temp #100 038-178 Hordwere Package 045-124 Front ene! Lew Grommet 078-005 Fuseholder 178-099 Line cord 170-019 hudio coble 170-015 15C011257-M8075-2 Vw32 $.8. No. | SERVICE BULLETIN CORRECT POSSIBLE SHORTING CONDITION MODEL: C 32 Preamplifier Serial No.: Below AYI295 PURPOSE OF MODIFICATION: To correct the condition where by the pre- amplifier's headphone amplifier channels are shorted together when plugging headphones into the top headphone jack. WHEN MODIFICATION SHOULD BE MADE: When any other service is performed on the unit. McINTOSH MODIFICATION KIT NO.: No kit available, PARTS REQUIRED: QUANTITY PART NUMBER DESCRIPTION 2 136453 Res. = 1002, 10%, IW ROK3, Qt PROCEDURE: 1, Remove top cover. 2. Make a sketch of the connectors connections to the head= phone monitor PC boards. 3. Remove the connectors from headphone monitor PC board and remove headphone monitor PC board from the chassi 4, Replace jump wire that jumps K901 to connector pin 28 with a 136453 1002 10% IW resistor. 5. Replace jump wire that jumps K901 to connector pin 24 with a 136453 1002 10% IW resistor. 6. Reinstall the headphone monitor PC board and replace top cover. TON "A'S ze 9 (OVER) Mcintosh Laboratary Incorporated 2 Chambers Street Binghamcon, New York 13903 Phone: Ares Code 607-723-3512REMOVE JUMPERS AND REPLACE WITH 1009 i IW RESISTORS. ; HEADPHONE. MONITOR PC BOARD INI 045-116 039-0614c 32 S.B. No. 2 SERVICE BULLETIN MODEL: ¢ 32 Preampli Below AY2076 " PURPOSE OF MODIFICATION: To eliminate.os record switch from any tape posit puts are in use, llatiof when switching the 9 to another when tape out- WHEN MODIFICATION SHOULD BE MAQ! hen, oscillation. PARTS REQUIRED: ~ QUANTITY PART: MBER _-- DESCRIPTION 2 066216 a 1dr, 36v Electrolytic . ~ Capacitor 3 070085 6. av Zener Diode PROCEDURE: Font 1, Remove front panel and bottom cover, 2, Remove record switch with PCB... ....- 3. Lift the base leg-of Bath tratsister (9301, 9302, and Q303) off the PcB. * 4, insert banded end of zener diode into holes on component side of PCB and solder other end to the transistor's base Teg. 5. Solder the capacitors from zener to emitter of each transistor on the foil side of PCB, Connect (+) terminal of capacitor to zener. 6. Install record switch, Insert and tape ribbon cable. 7. Replace front panel and bottom cover. e, 039-0668 8 Mcintosh Laboratory Incorporased ‘2. Chambers Street Binghamton, New York 13903 fone: Ares Code SU7-723.9812c 32 $.B. No. 3 SERVICE BULLETIN PREVENT FALSE TURN ON OF PREAMP MODEL: C 32 Preamplifier PURPOSE OF MODIFICATION: To prevent false turn on of preamp by auto ON" circuit. WHAT UNITS ARE AFFECTED: All units with Serial No's. below AY2289 WHEN MODIFICATION SHOULD BE MADE: When any other service is performed on the unit. PARTS REQUIRED: QUANTITY PART NUMBER DESCRIPTION 1 061113 Disc. Cap. O.1NF 100v +80 -20% (Dual) PROCEDURE: 1. Remove bottom cover, 2. Locate the 045121 - Auto-On PC board. 3. As indicated, solder disc. capacitor on to the foil-side of the PC board, between the cathode and gate of Scr 4001. 4, Replace bottom cover, 5. Check unit for normal operation AUTO-ON PC BOARD 045442) € °ON *a°S zwe2 039-092 Mcintosh Laborstory tncorporated 2 Chambers Street Binghamton, New York 13903 Phone: Area Code 607-723-3512