Sansui AU 70 Owners Manual
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Extracted text from Sansui AU 70 Owners Manual (Ocr-read)
Page 1
This amplifier has a maximum output of 50 watts (25W-25W) and features an amazingly lo w distortion factor of not more than 0.15% at 20W. A high- quality amplifier with many exci ting features, it is delivered to you with Sansui's fullest confidence. This booklet explains the steps necessary for operating and caring for your new the . AU-70 . Read an the instructions carefully and retain for future use. CONTENTS FEATURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3, 4 SPECIFICATIONS ..... ... .. ... ... . .. ... ... .. . ... ..... ........... . 5 CHARACTERISTICS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 CONNECTIONS.......................................... ...... .... 7, 8, 9, 10 SWITCHES AND CONTROLS ........ ...... .......... .... ...... 11, 12 OPERATIONS.... ................ .... .... .... ...................... 13, 14 HI NTS ON USE ................ ................ ................ .. 15, 16 SERVICE NOTE ................ .......... ...... ...... ............ 17, 18 PA R TS LIST ...... ...... ....... .... ......................... .... .. 19, 20, 21 SC H EMATIC DIAGRAM .......... ........ ... . .......... ....... . 22 PARTS LAyOUT ... ..... . ... ... . ............ ... .. ..... ....... ... .. . 23 SUI STEREO CONTROL AMPLIFIER AU-70
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FEATURES 7189A P.P. PRODUCES 40W WITHOUT PISTORTION (MAX . 0.95 % AT 30 CPS AND ·0.15 % AT 1,000 CPS ) The 7189A power tubes operate in class AB,P .P. (fixed bias) Jor high-fidelity reproduction. Their combined . maximum output is limited to 50 W. The amplifier incorporates a multiplex feedback circuit (total negative feedback: 26 dB) for the first time in this class of amplifiers in Jilpan. This makes it extremely low in distortion over th e w hole frequency range. Total harmonic dis tortion at 1 kc is 0.15%. At 30 cps, a very low frequency at which it is extremely difficult · to minimize ha rmonic distortion, the distortion is limited to not more than 0.95% . This is quite a feat for a 50-watt amplifier. Another remarkable feature is the damping factor of 18, a figure which is lower than that of triode power tubes ' coupled in P .P . This is why bass sounds come out with such clarity . - 3 NFB USED IN ALL AMPLIFIER CIRCUITS , FROM PREAMP TO POWER AMPLIFIER The low distortion of the power amplifier is meaningless if the preamplifier generates distor tion s. Your AU-70 uses a three -stage amplifier circuit in its interm ed iat e or cpntrol amplifier unlike conventional one-stage control amplifiers and has all its circuits in a single negative -feed back loop. These make your AU - 70 free from noise and distortion. SUPER-PRECISION TRANSISTOR PREAMP LIFIER ELIMINATES HUM AND NOISE The exclusive Sansui four-transistor preamplifier, which features a transistor circuit factor of 4-as compared with conventional 5-1O-al1d a transistor noise factor of 2 dB-as compared with conven tional 5 dB, eliminates hum and noise, the enemy of high -fidelity reproduction. The amplifier has a much better S IN ratio and a gain three times larger than vacuum-tube amplifiers. EACH CHANNEL CAN BE OPERATED IN DEPENDENTLY EQUIPPED WITH TONE DEFEAT Each channel has independent tone contro ls for bass and treble. This makes fine adjustment possible. Moreover, each channel is eq u ipped with tone defeat which cance ls the tone control circuits. You can easily obtain a flat frequency response without causing any undulation in response or redu ced gain in bass and treble as in the case of conventional mechanical control by means of a tone volume knob. Therefore, you ca n get an accurate, perfectly flat response from your AU-70 just by flipping a switch. BLEND CIRCU IT PERMIT CONTINUOUS SHIFT FROM MONAURAL . TO STEREO As you turn the "BLEND" sw itch clockwi se, y our AU - 7 0 gradually shifts from monaural to stereop honic repr~duction. This feature enables you to get full stereophonic effect by compensa ting program sour ces which give a, particularl y s tron g effect of the conce rt ha lL EA SY-T O - READ THREE -RAN GE OUT PUT LEV EL METERS Each output level meter can be switched ove r t o a n y of the three scale s of 5, 10 and 25 watts. The meters not only give direct readings of both ch anne ls , but a lso indicate any lack of balance between the right and left outputs. These pro ve ve ry useful in balancing the outputs . THREE -DIMEN SIONAL PERFORMANCE POSSIBLE WITH CENTER -CHANNEL OUTPUT TERMINAL Y~ur AU -70 ha s an ou tput terminal for the center -c h annel amplifier. Connect it to your monaural amplifier to produ ce a three-dimensional effect. EQUIPPED WITH ADVANCED , HIGH PERFORMANCE ACCESSORY CIRCUITS Your AU -70 is equipped with various advan ce d acc ess ory c ir cuits such as loudness control, low an d high filters, tape monitor, tone defeat, pre sence, blend, spe ak er sw itch and headphone jack . - 4-