Luxman-Rx-103-1983-09-3-Us 电路图 维修手册.pdf

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1、EQUIPMENT PROFILE LUXMAN RX-1 03 RECEIVER Manufacturers Specifications FM Tuner Section Usable Sensitivity: Mono. 10.3 dBf (1.8V/300 ohms). FiftydB Quieting Sensitivity: Mono, 16.4 dBf (3.611V/300 ohms). S/N: Mono, 78 dB. THD: Mono, 0.05% at 1 kHz, 0.06% at 100 Hz, 0.08% at 6 kHz; stereo, 0.06% at1k

2、Hz, 0.08% at 100 Hz, 0.10% at 6 kHz. Capture Ratio: Wide, 1.2 dB; nar- row, 3.3 dB. Image Rejection: 70 dB. M. Rejection: 100 dB. Spurious Response Rejection: 85 dB. AM Suppression: 65 dB. Alternate Channel Selectivity: Wide, 60 dB; narrow, 90 dB. Adjacent Channel Selectivity: Wide, 6 dB; narrow, 20

3、 dB. Stereo Separation: Wide, 55 dB at 1kHz. SCA Rejection: 60 dB. AM Tuner Section Usable Sensitivity: Loop, 550 ILV per m; external antenna, 15 ILV. Image Rejection: 40 dB. S/N: 50 dB. THD: 0.3%. Amplifier Section Power Output: 90 watts per chan- nel,both channels driven, 8 -ohm loads, 20 Hz to 20

4、 kHz. Rated THD: 0.018%. Input Sensitivity: MM phono, 2.5 mV for rated output; MC phono, 150 V for rated output; high level, 150 mV for rated output; main amplifier, 950 mV for rated output. Phono Overload: MM, 200 mV. S/N: MM phono, 86 dB; high level, 102 dB. Residual Noise: 0.5 mV. Tone Control Ra

5、nge: Bass, +7 to - 10 dB at 100 Hz; treble, +6 to - 10 dB at 10 kHz. Subsonic Filter: 30 Hz, 6 dB/oc- tave. HighCut Filter: 7 kHz, 6 dB/octave. Loudness Control: Volume at -30 dB, +8 dB at 100 Hz, +7.5 dB at 10 kHz. General Specifications Power Consumption: 120 V, 60 Hz, 3.1 A. Dimensions: 17.8 in.

6、(45.3 cm) W x 5.8 in. (14.7 cm) H x 17.9 in. (45.5 cm) D. Weight: 34.1 lbs. (15.5 kg). Price: $995.00. Company Address: Luxman Divi- sion, Alpine Electronics, P.O. Box 2859, Torrance, Calif. 90509. For literature, circle No. 95 80 AUDIO/SEPTEMBER 1983 RadioFans.CN 收音机爱 好者资料库 Cosmetically, the RX-103

7、 is a far cry from some of the earliest Luxman receivers to arrive in this country some 10 years ago when that 55 -year -old company first established its own subsidiary in the United States. Those receivers were widely acclaimed for the elegance of their styling (a senior engineer and director of t

8、he Lux Corporation of Ja- pan had the last word on product design and styling, and his sense of good taste was unerring) as well as for their excellent sonic and measured performance. Front panels were always somewhat understated and subdued, with col- ors carefully chosen, knobs painstakingly selec

9、ted to com- plement the rest of the panels accoutrements. One felt the overall appearance without was consistent with the superb electronic performance within. Let me say at the outset that the superb performance is still very much present in this latest round of receivers, if the top -of -the -line

10、 RX-103 is any indicator of the rest of the line. As for the styling, well, Im sure there are those who will love the RX-103s clear lucite-block pushbutton selectors, flash- ing LED indicators (which abound and, in actual use, do perform useful functions), its busy arrays of rotary knobs and pushbut

11、tons, and its four -tone color scheme (more, if you count the colors of the various indicator lights). Isus- pect that there are some who will even love Servo -Face. What is Servo -Face, you ask? Itis Luxmans name for its futuristic motor -driven section of the front panel. With power off, the right

12、 half of the panel rests flush with the front surfaces of the rotary bass, treble, balance, oudness and master volume controls, at the same time covering up seven small pushbuttons which handle secondary functions of tape monitor selection (there are two circuits here), tape dubbing, subsonic and hi

13、gh -cut filter activation, mono/FM muting, and MM/MC cartridge input selection. Push the power switch at the lower left of the panel and the gentle whirring of a motor is heard, as the Servo -Face section of the panel recedes so that you can get at the aforementioned knobs and buttons. I am informed

14、 that the practical purpose of Servo -Face (I just love that name, dont you?) is to prevent idle fingers from upsetting pre- ferred control settings when the master of the system is not present.Ifthatis so,it would seem to me to be more important that Servo -Face operate in just the reverse way- blo

15、cking access to the knobs when the receiver is turned on and working. As Isaid, you will either love it or think it a bit silly, but it should in no way detract .from an appreciation of the excellent audio and r.f. engineering which has gone into the RX-103. To the left of the Servo -Face section of

16、 The panel are several transparent lucite blocks which serve as program source selector buttons (FM, AM, Phono and AUX) and as Up and Down AM or FM tuning buttons for the frequen- cy -synthesized tuner. When a given program selector but- ton is pushed, subdued red lighting is emitted from behind tha

17、t button and is visible in front of the button. Blocks at the extreme left end of the panel serve as the power on/off switch and as speaker selector switches (one or two pairs of speakers can be connected to the RX-103). Just to the right of these are Store, Memory Scan, and eight preset station but

18、tons, plus a button labelled FM Memory A/B. With the aid of this last-named button, itis possible to store 0 -40 60 801 1020 ?HM ANTENNA TERMINALS 550 978 17405500 MONO S/N 78 dB STEREO S/N. 74dB STEREO THD 6.06 /. MONO THO 0.06% 6065,0 SIGNAL INPUT FOWF6- dE0 (0 4E91 Iz 10-15 WATTS) Fig. 1-Mono and

19、 stereo quieting and distortion characteristics, FM section. 0 0.10 0! 10 - 10 0 2 0 Cc insto .0111111Malinill STEREO 111111311111111.FINAi ams-iiiirmaii2sitak%-risa 00-1111=arsoormaimummless immunmommin 111101 IMEINE_11_1_111111M11 111111011111111111 BUD 00 1k Fig. 2-TH D vs. frequency, FM tuner se

20、ction. Fig. 3-Frequency response (upper trace) and stereo separation (lower trace). FM tuner section. FREQUENCY - Hz !Ok20k 800 40 60 80 z 0 2 AUDIO/SEPTEMBER 1983 81 RadioFans.CN 收音机爱 好者资料库 It was obvious from the listening tests that Luxmans engineers had not lost their touch-or their sense of wha

21、t constitutes good sound. Fig. 4-Spectrum analysis of crosstalk products for a 5 -kHz, left -only signal, FM tuner section. Fig. 5-Frequency response, AM tuner section. up to 16 favorite FM stations, since stations can be memo- rized as Ai, A2, etc. or B1, B2, etc. depending upon the setting of the

22、NB switch when a given station frequency is placed into memory. When AM reception is selected, how- ever, only eight favorite station frequencies can be stored since the NB switch is not active in the AM tuning mode. Most of the remainder of the front panel is devoted to forms of display, including

23、a fluorescent power output level display, preset station indicators, numeric frequency dis- play (in MHz for FM or kHz for AM), signal strength indicator, FM tuning indicator (which lights up when optimum tuning has been achieved), and a stereo indicator. In addition, there are several tiny red LED

24、indicators which light up to tell you what Luxmans automatic Computer Analyzed Tun- ing (C.A.T., for short) is doing. This circuit adjusts such tuner parameters as i.f. bandwidth (narrow and wide set- tings are not user selectable, but are adjusted according to reception conditions sensed by the tun

25、er), antenna atten- uator, high -blend circuit, and an anti -birdie filter. Any or all of these may be turned on automatically, and if they are, associated LEDs in the display area tell you so. Of course, if you dont agree with C.A.T.s decisions you always have the option of depressing a C.A.T. on/o

26、ff button located to the right of the display area. A headphone jack and a remote- control on/off switch complete the front panel layout. A hand-held infrared remote control unit supplied with the RX-103 enables you to operate many of the receivers func- tions remotely (power on/off, volume, muting,

27、 input selec- tion, memory scanning, FM NB selection and tape monitor switching). And if you happen to own Luxmans matching turntable (PX-101) and matching cassette deck (their KX- 102 or KX-101), multiconductor cables provided with those components connect to special sockets on the rear panel of th

28、e RX-103, enabling you to operate most of the controls on theSe other components from the same remote, too. Coaxial as well as screw -terminal 75 -ohm antenna con- nection facilities, plus 300 -ohm and external AM antenna terminals are grouped together at the upper left of the rear panel. A true AM

29、loop antenna is supplied separately and snaps into a bracket on the rear panel, and it can be oriented for best AM reception. In addition to the usual array of phono- and high-level input and tape input and output jacks, the rear panel of the receiver is equipped with pairs of Preamplifier Output an

30、d Main Amplifier input jacks, plus a switch to connect and disconnect these two sections of the receiver to plug sound processors into the signal path. Two sets of color -coded speaker connection terminals, four convenience a.c. receptacles, and a chassis ground termi- nal complete the rear panel la

31、yout. Circuit Highlights Neither the owners manual nor the press releases issued by Alpine, who have the American distributing rights for Luxman products, tells us very much about the circuitry of the RX-103 receiver. We do know that the amplifier section uses Luxmans well-known Duo Beta circuit whi

32、ch pro- vides minimum overall loop feedback in the audio range but adds a second subsonic feedback loop to reduce output impedance at near-d.c. frequencies and reduce various forms of dynamic intermodulation distortion, in addition to stabilizing the output stages against d.c. drift. Havingex- plore

33、d this circuit in earlier amplifiers,I can tell you that it is a valid and effective approach to audio power amplifier design, one that has been emulated by several other firms who specialize in superb -sounding high -end amplifiers. The tuner section employs frequency -synthesized tuning, of course

34、, with the added attraction of that innovative C.A.T. circuit that takes the guesswork out of optimum FM tuning. FM Measurements Usable FM sensitivity in mono measured 10.8 dBf (1.9 V across 300 ohms), while stereo usable sensitivity was 18 dBf (4.4 V/300), just a bit above the ideally set stereo sw

35、itching threshold of 17 dBf. Fifty -dB quieting in mono required an input signal strength of only 14.7 dBf (3.0 V/ 300 ohms), while in stereo, the 50 -dB quieting level was reached with an input signal of 37.2 dBf (40 V). At 65-dBf signal level, signal-to-noise ratio in mono was 78 dB, exactly as sp

36、ecified by Luxman, while at the same signal strength input in stereo, S/N measured 74 dB. Harmonic distortion, for a 1 -kHz modulating signal, measured 0.06% in both mono and stereo. Distortion and quieting for both mono and stereo reception are plotted as a function of signal input levels in Fig.1,

37、 while in Fig. 2 Ihave plotted harmonic distortion versus audio frequency (for strong signal levels) 82 AUDIO/SEPTEMBER 1983 RadioFans.CN 收音机爱 好者资料库 Dynamic headroom was high for a receiver in this power class, a full 1.7 dB. In music power terms, that means it can deliver short- term peaks of 133 w

38、atts. for both mono and stereo. At 100 Hz, THD was 0.1% in mono and 0.13% in stereo, while at 6 kHz, distortion was 0.1% in mono and 0.11% in stereo. Figure 3 is a scope photo taken from my spectrum analyzer. Sweeps are logarithmic from 20 Hz to 20 kHz. The upper trace shows stereo FM frequency resp

39、onse for the FM tuner section of the Luxman RX-103; deviation from flat response was no more than +0.3 dB or -0.4 dB at any frequency from 30 Hz to 15 kHz. The lower trace shows crosstalk or separation as measured at the output of the unmodulated channel. Separation measured an outstand- ingly high

40、58 dB on one channel and 61 dB on the other at 1 kHz. At 100 Hz, the separation readings were 47 and 48 dB, while at 10 kHz, separation was still a very high 39 dB for each channel. Figure 4 illustrates what happened when Iapplied a 5 - kHz modulating signal to the left channel. The tall spike at th

41、e left of the scope display is the desired output signal. Sweep was linear this time, extending from 0 Hz to 50 kHz. The second sweep shows what was present at the output of the unmodulated channel. Separation is indicated by the shorter spike nestled inside the desired output indication, and amount

42、s to around 46 dB at that frequercy (scope vertical sensitivity is 10 dB per division). Other crosstalk components, seen to the right of the display, consist of of the 5 -kHz modulating signal, small amounts of 19- and 38 -kHz outputs, and one or two other spurious crosstalk signals. Because of the

43、automatic action of Luxmans C.A.T. cir- cuitry, it was not possible to force the tuner into its narrow i.f. mode on the test bench. Therefore, we were only able to measure remaining i.f.-bandwidth-dependent parameters in the normal or wide position. Under those conditions, cap- ture ratio measured a

44、n excellent 1.1 dB, while alternate - channel selectivity was 63 dB. Image rejection measured 73 dB while i.f. and spurious rejection measured 100 and 88 dB respectively. Figure 5 is the usual frequency response curve for the AM tuner section of the receiver.If you are willing to tolerate a - 6 dB n

45、otation (the way most manu- facturers quote AM frequency response, if they quote it at all), the response of this AM section is really not all that bad, extending as it does from around 65 Hz to between 5 and 6 kHz. Power Amplifier and Preamplifier Measurements The power amplifier section of the Lux

46、man RX-103 deliv- ered a full 100 watts per channel at mid -frequencies before THD reached the rated level of 0.018%. The reason for Luxmans 90 -watt rating was obviously the power limits at 20 Hz and 20 kHz, which turned out to be exactly 90 watts, as claimed. Dynamic headroom was rather high for a

47、 receiver in this power class, measuring a full 1.7 dB. Translated to music power terms, this means that the amplifier can deliver short-term signal peaks of 133 watts per channel without clipping. Figure 6 is a plot of THD versus power output for the three key test frequencies of 20 Hz, 1 kHz, and

48、20 kHz. Damping factor for the power amplifier measured 47, re- ferred to 50 Hz and 8 -ohm loads. Considering the low amount of overall feedback employed in the Duo -Beta cir- cuitry,I was impressed with the receivers relatively low o.o I- 0001 I kHz 20 Hz - 20 kHz 1111111111111111111111111111111111

49、 ILIETP11111111.11111111111 NNmuuliniTemossummammilummeimmainewaril 111M1=111101111111111111emililarmallIMISIMI ei lull 111111111N1111.11111111111111111 0110100100.0 POWER/CHANNEL - WATTS Fig. 6-Power output per channel vs. THD. Fig. 7-Tone control and filter characteristics. 1000.0 80 100 output impedance, as indicated by such a high damping factor. The ampl.fier operated safely into 2 -ohm loads, and it was stable under a wide variety of capacitive and inductive loading conditions. CCIF-IM (twin tone) distortion measured 0.0027% at rated output, while IHF-IM was lower than 0.01%, the lo