User manual PIONEER SA-610 service manual

[. . . ] ff o'll , r*:(' EefvicecVlanual S \-Ci, lO S T E R E OA M P L I F I E R ()rrroruEErl' to o This service manualis applicable the KU type. CONTENTS I. SPECIFICAT|ONS 2. BLOCKDIAGRAM 6. LEVELDIAGRAM T. CTRCUITDESCRIPTIONS. . . . . . . . . 6 . . . . . . 8 . . . . . . . 8 . . . ' . . . . . . 10 9 6 P D 1 0 . C . B O A R D P A T T E R N SA N D P A R T S L I S T 1 0 . [. . . ] Turn the balance control to the left and adjust. Conversely, the soundappears be louderon the left, if to it meansthat the volume of the left channel is higher. Therefore, turn the balancecontrol to the right and adjust. swtrcH @ rorue Set this switch to ON when adjusting the bassand treble controls. When set to the upper (OFF) position, the tone control circuits are disengaged frequencyresponse and is flat. This function is convenient checkingphono carfor tridge and speaker tone quality and listening room acoustics. r @ powentNDtcAToR When the power switch is set to ON this lamp lights up, i n d i c a t i n gh e a m p l i f e r i s t u r n e do n . DISASSEMBLY Bonnet Case Removethe four screws o . Bottom Plate Removethe six screws O. \o. . oo/o' Bonnet case Front panel 4. PARTS LOCATION FrontPanelView o The !i, marh found on some component parts indicates the importance of the safety factor of the part. There' fore, when replacing, be sure to use parts of identical designation. m (t . J!g!r. - K n o b( B A L A N C E I AAB. 223 Leverknob ( L O U D N E S S , A P E2 ) T AAD. 2OO 6 siA-610 Front View with Front Panel Removed F l u o r e s c e n ti n d i c a t o r t u b e AAV-O06 V a r i a b l er e s i s t o r( B A S S . T R E B L E ) ACT-127 Slide rotary switch (FUNCTION) A S X - I1 3 sl ide rota ry r*i t"tr -------]-=---. ' (SPEAKERS) : I" ASE-oo3 I L e v e rs w i t c h ( P O W E R ] | , , ll '!'tlr ' I o L:---Variable r e s i s t o r( V O L U M E ) 'l I tu " V a r i a b l er e s i s t o r( B A L A N C E ) ASK. 520 Headphones . jack AKN-023 ACT-130 -Lever s w i t c h( T A P E2 ) ASK. 172 Leverswitch ( LOUDN ESS) ASK-171 f L e v e rs w i t c h ( S U B S O N I C , O N E ) T A S K - 17 1 Top View with Bonnet Removed rl|r j Powertransformer ATT-667 A F a m p l i f i e ra s s e m b l y GWK. 144 Switch assembly GWS-215 Switch assembly GWS-216 Volume assembly GWX459 t- t Headphones ssembly a GWX460 Tonecontrolassembly GWG-138 I AC socker AKP. O32 RearPanel View 1i Power code ADG-023 T e r m i n a l{ I N P U T ) AK8. 064 T e r m i n a l( T A P E 1 ) AKB-063 Strein reliel AEC-327 Terminal(SPEAKERS) AKE-051 5. BLOCK DIAGRAM swtrcHEs: st Fu&trox luxEP-M-raPEI-AUX 32 t3 54 55 s6 se fAPE?ouoils Su6oirt(t5Hrl SPEAXERS &sR ioilE ON - 6F ox - gll Ox - 6 O'F-A-' ox -!Il or _lI! 6 . L EV E L DI A G RA M l}. tlJ"roo't (eo) xeai pnone AUX /TUNER 15OmV siA-61 cl n 7 . C I R C U I TD E S C R I P T I O N S Equalizer Amplifier The 54, -610 features a 3-stage direct-coupled equalizer amplifier for greater reduction of noise and distortion. Besides the use of an ultra low-noise transistor (25C26O2) in the first stage, the adoption of low impedance input resistance and equalizer circuit has contributed to an S/N ratio of at least 82dB (at 2. 5mV input, IHF-A). Power Amplifier This all stage direct-coupled pure complementaly SEPP circuit features a current mirror load differential amplifier in the first stage, and incorporates the tone control circuit in the NFB loop. Although the incorporation of the tone control circuits in the power amplifier stage reduces the number of elements that the signal has to pass through, and thereby further reduces noise, distortion, and cost, the power stage does require a higher gain and a higher degtee of stability. In the SA-610, this high gain and high stability are achieved by a cunent mirror load differential amplifier in the first stage and by the use of a constant current circuit for the load of the predriver stage. Furthermore, the tendency for the pre-driver stage capacitance impedance load to cause deterioration in the high end frequency responseis suppressedby inserting a capacitor (C) between the emitter of the pre-driver stage (Q2) and the baseof the constant current circuit (Q1) as shown in Fig. At frequencies where the reactance of this capacitor may be ignored, the push-pull action of Ql and Q2 servesto counteract the high end frequency response deterioration. The power amplifier stage is a complementary 2-stage' Darlington connection, resulting in an output power rating of 45W + 45W (8Q, 20Hz2OkHz\, harmonic distortion of less than O. O37o (20H2 20kHz at rated output), and output power bandwidth of 5Hz - 50kHz (0. O3% THD). Certainly a superb performance for an amplifier of this classis obtained. /. Constant circuit current rl I !f' Protection Circuit Besides protecting the speakers if a DC voltage should happen to appear at the power amplifier stage outputs, this circuit also mutes the signal path when the power switch is turned on and off (SeeFig. If for any reason a DC voltage (in excess of about tbV) should happen to appear in the output of the power amplifier stage, it is detected immediately by either Q23 or q24. [. . . ] t I I I D L 1 2 3 -l R5l 2. 2k D3 rs2075 c39 o. ot/ 500 l I S W I T C HA s s ' y - GWS -?15 _ I t- asE-oo3 '-^ i--T--i f c67 27p I 82P ol ts2076 2SC19r4A-G ; ??'?t I ---"J"-l F ttr-J 'o* 56 u'tt*' SB%, , l !* tok cto o. 00r2 Rrol 6 . 2t c68 27o l'" nea'6zr YFl, i. , I d l"F *^^-J R92 ilOk c6l roo, /so Q2 HAr20tO RzO lgk RzZ tO C48 ) L A s s ' y( 2 / 2 1 G W G- 1 3 8 _^. -J?rJ , r. 3i. R52 I az6 2scrass-R "ro A I o r rc e z s o AIC58 4A - O. 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