McIntosh MC 275 Service Manual
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Extracted text from McIntosh MC 275 Service Manual (Ocr-read)
Page 1
600 A/70.7 OUTPUT RECEPTICAL CONNECTIONS PIN 1-GROUND, 70.7 V RETURN, AND 600 A C.T. PINS 1 AND 7- LEFT 70.7 V OUTPUT PINS 2 AND 3 - LEFT 600 A OUTPUT PINS 1 AND 8 - RIGHT 70.7 V OUTPUT PINS 4 AND 5- RIGHT 600 A OUTPUT SINGLE CHANNEL (MONO) OUTPUT NOTE FOR SINGLE CHANNEL OUTPUT PARALLEL OR SERIES CONNECT THE L AND R OUTPUTS TO OBTAIN DESIRED OUTPUT IMPEDANCE. * 5% TOLERANCE RESISTORS A FOLLOWING COMPONENTS ARE MATCHED TO 1%: R11 AND R36 R13 AND R38 R24 AND R27 R49 AND R52 VOLTAGE AND RESISTANCE CHART "This resistance measured with condenser C25A shorted to ground. "This resistance measured with condenser C24B shorted to ground. High impedance VTVM is used to measure the operating voltages. Resistance in Ohms Unit Off AC Volts at rated output DC Volts No. Signal Pin No. Tube 160K* 1M 3.3K 0 160K* 1M 3.3K 2.1 .47 .44 0 2.1 .47 .44 6.3 100 0 .95 0 100 0 .95 0 1 2 3 4&5 6 7 8 9 12AX7 (VI) 37K* 160K* 18K 0 40K* 2.4M" 18K 0 12 2.1 .96 0 12 0 .96 6.3 240 100 106 0 240 84 106 0 1 2 3 4&5 6 7 8 9 12AU7 (V2 or V5) 12K* 210K 2.7K 0 12K 210K 2.7K 0 152 12 .7 0 152 12 .7 6.3 365 22 40 0 365 22 40 0 1 2 3 4&5 6 7 8 9 12BH7 (V3 or V6) 38** 1M 170K 0 38** 1M 170K 0 112 152 149 0 112 152 149 6.3 205 -57 -57 0 205 -57 -57 0 1 2 3 4&5 6 7 8 9 12AZ7 (V4 or V7) 0 38 260 170K 6 15 0 or 6.3 116 112 149 6.3 or 0 116 0 450 450 -57 0 .6 1 2 3 4 5 6 7 8 KT88/6550 (V8, V9, V10.V11)
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SC 125-109 C