Ampex-601-Operation-Maintenance 电路图 维修手册.pdf

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1、PIEX L 601 TM 1001 Operation Maintenance Manual AMIPIEX C O R P O RAT I O N 934 CHARTER STREET REDWOOO CITY CALIFORNIA 3rd EDITION OCTOBER 1958 Table of Contents I. DESCRIPTION AND SPECIFICATIONS 1-1 GENERAL 1-1 SPECIFICATIONS l-2 n. PRINCIPLES OF OPERATION 2-1 THEXRY 2-1 m. INSTALLATION AND OPERATI

2、ON 3-1 GENERAL 3-1 POWER 3-1 LINE INPUT 3-1 MICROPHONE INPUT 3-1 REPRODUC;E OUTPUT 3-1 INTERCONNECTING 3-2 CONNECTORS 3-2 STUDIO INSTALLATION 3-2 TAPE THREADING 3-3 RECORDING WITH HALF TRACK MACHINES 3-4 REPRODUCING WITII HALF TRACK MACHINES 3-4 RECORDING 3-4 REPRODUCING 3-5 REWIND AND FAST FORWARD

3、3-5 ERASING 3-5 MIXING 3-5 SYNTHETIC REVERBERATIONS 3-6 IV. TAPE TRANSPORT ASSEMBLY 4-1 GENERAL 4-1 STAND-BY OPERATION 4-1 PLAY MODE 4-1 REWIND MODE 4-3 FAST FORWARD MODE 4-3 ROUTINE MAINTENANCE 4-4 V. ELECTRON! C ASSEMBLY 5-1 GENERAL 5-1 RECORD CHANNEL 5-1 REPRODUCE CHANNEL 5-1 BIAS AND ERASE OSCIL

4、LATOR 5-1 ELECTRONIC ALIGNMENT 5-2 ALIGNMENT AND Tll!T EQUIPMENT REQUIREMENTS 5-2 VI. PARTS LIST 6-1 List of Illustrations Fig.No. CaPtion Page FRONTISPIECE 2-1 TAPE MAGNETIZATION 2-1 2-2 RECORDING HEAD 2-2 2-3 MAGNETIZATION CURVE 2-3 2-4 OUTPUT VS. FREQUENCY 2-4 2-5 ACHIEVING FLAT RESPONSE 2-5 3-1

5、SPACE REQUIREMENTS 3-2 3-2 TAPE THREADING AND NOMENCLATURE 3-3 4-1 . MECHANICAL OPERATION SIMPLITIED 4-2 4-2 ROUTINE LUBRICATION 4-3 4-3 TAPE TENSION MEASUREMENTS 4-5 4-4 TAPE TRANSPORT EXPLODED VIEW 5- 1 REPRODUCE AMPLIFIER RESPONSE 5-4 5-2 RECORD AMPLIFIER RESPONSE 5-7 5-3 SCHEMATIC DIAGRAM I. Des

6、cription and peak record level includes bias, erase and re- produce amplifier noise. Half Track-50 db below peak record level. MICROPHONE: Accommodates any high impedance microphone, and can be quickly converted for a low impedance microphone with the plug-in accessory transformer ( Cat- alog No. 17

7、331-1). LINE: 0.5 volt required for normal program level. 1.2 3 volts rms into 600 ohms at program level. PLAY-REC: The play mode is selected by placing the switch in PLAY position. - The record mode _can be selected only. by de- pressing the safety button at the same time the seleccor switch is pla

8、ced in REC position. The safety button, a flat topped neon lamp, remains lighted while the machine is in the record mode. REWIND-FAST FWD: This selector switch is mechanically interlocked with the FLAY-REC switch. Reproduce Output Operating Controls Miscellaneous Monitoring Head Assembly Power Requi

9、rements Accessories MIC REC LEVEL, and LINE REC LEVEL are separate mixing controls. The MONITOR SELECTOR switch is used for monitoring as described in the following paragraphs; bur ic functions also as an oper- ating control. In the PLAY mode, the MON- ITOR seleccor switch must be in the TAPE positi

10、on in order to bring the reproduce head signal to the OUTPUT. A toggle ON-OFF switch, located on the control panel, turns power on or off. When placed in the ON position, this toggle switch will cause the capstan co rotate; but the tape will not move until one of the two operating switches is turned

11、 from its neutral position. The MICROPHONE input, a three circuit connector, is conveniently located on the con- trol panel. The PHONES output is a two circuit jack, located on the front panel. The LINE INPUT connector is a cwo circuit jack recessed into the right side of the equip- ment. The OUTPUT

12、 connector is a three circuit jack also recessed into the right side of the equipment. Mating connectors are supplied ( see Table 1-1). . The MONITOR SELECTOR switch allows monitoring of program input, or reproduce output. A phone jack and illuminated v-u meter are on the front panel. When the TAPE

13、position is selected, the re- produce output can be monitored. When the. INPUT position is selected, the headphones and meter report program signal level. Separate erase, record, and reproduce heads are contained jn a sjngle housing. 117 volts, 50 or 60 cps; 0.52 ampere, 61 watts. Majmenance Kit: Sp

14、eed Conversion Kits to: 3 ips, 60 cps 7 ips, 60.cps 3 ips, 50 cps 7 ips, 50 cps 6392-1 7556-0 7556-1 7556-2 7556-3 SPECIFICATIONS 1-3 SPECIFICATIONS Accessories 1-4 Conversion Kit co: 50 cps operation, 7 1ps 60 cps operation, 7 ips 50 cps operation, 3 ips 60 cps operation, 3 ips . Adaptor for rack m

15、ounting Spare parts kits for: 7 ips, 60 cps machine 7 ips, 50 cps machine 3 ips, 60 cps machine 3 ips, 50 cps machine Minor hardware Kits: 9738 9739 9740 9741 9684-1 9742-1 9742-2 9742-3 9742-4 7802 See Section VI for a complete parts list. II. Principles of Operation If a material capable of being

16、magnetized is placed in the proximity of a magnetic field, the molecules of the material will be oriented according to the direction of the field. Any of several methods can be used to produce the magnetic field, but of most interest in magnetic recording is that field produced when a current flows

17、through a coil of wire. The current may be derived from a transducer-for example, a microphone converting audio sound waves to electric current. Magnetic recording tape consists of finely divided iron-oxide par- ticles deposited upon a plastic backing. This tape is moved through a magnetic field in

18、which the magnetizing force is alternating, and the iron oxide particles are aligned according to the instantaneous direction and magnitude of the field ( See Fig. 2-1). TAPE DIRECTION -. TAPE s N s FLUX N s :=i :=i s N SIGNAL -.7-1-.-11. . -.-e Fig. 2-1. Tape Magnetization Magnetic Tape 2-1 Magneti

19、c Head The magnetic field is produced in the gap of a recording head, over which the recording tape passes. The recording head is a ring- shaped electromagnet ( See Fig. 2-2). le consists of an incomplete ring of high-ly permeable material inserted in a coil of wire. The discontin- uity in the ring

20、forms the gap, and the ring is the core of the electro- magnet. .-e-.t Fig. 2-2. Recording Head Magnetization Curve The magnetization curve of the iron oxide utilized as the recording medium is similar to that shown as the heavy line in Fig. 2-3. At points near the origin, the curve is extremely non

21、-linear, and the signal record- ed on the tape would not be directly proportional co the signal applied to the head. This would result in a high degree of distortion upon re- production. This distortion is greatly reduced by the application of a high-frequecy constant amplitude bias signal which is

22、mixed with the signal being recorded. The frequency of chis bias is generally selected co be five times the upper frequency limit of the recorder co prevent beating between the bias and harmonics of the recorded signal. 2-2 Bias While the cape is in the recording gap, the bias causes the magnet- iza

23、tion characteristics of the iron oxide co follow the dashed line loops shown in Fig. 2-3, known as the MINOR HYSTERESIS LOOPS. As the tape leaves the gap, the influence of the magnetic field created by the bias is reduced to zero, and the tape assumes a permanent magnet- ization, known as REMANENT I

24、NDUCTION, determined by the gap flux at the time the tape leaves the gap. After the recording process, there exists on the tape a flux pattern which is proportional in magnitude and direction co the signal recorded on it. If the tape is then moved past the gap of a reproduce head- which is similar i

25、n construction to the record head-the magnetic flux of the moving tape will induce a voltage in the coil of the reproduce H B (INDUCTION) MINOR HYSTERESIS LOOP SATURATION LEVEL lMAGNETIZING FORCE) I I 1-1- MAGNETIZATION i CURVE COMPOSITE SIGNAL AT RECORD HEAD I I 1 I -I I l=:a I I SIGNAL Fig. 2-3. M

26、agnetization Curve head. This induced voltage is proportional to the number of turns ot wire on the head, and the rate of change of flux, expressed in the fol- lowing equation: E = N (dfft) Where E is the induced voltage N is the number of turns of wire d)fit is the rate oi change of flux It is desi

27、rable that the gap in the reproduce head be as small as possible, so that the gap will intercept less than one wave length of the signal on the tape at the highest frequency to be reproduced. How- ever, as the gap is made smaller the induced voltage decreases, so there is a practical limit in decrea

28、sing the gap and still maintaining 1 an ade- quate signal-co-noise ratio. Induced Voltage in Head 2-3 2-4 Induced Voltage in Head The voltage induced across the head 1s computed by the following equation: Where E is the induced voltage B is the maximwn flux density of the recording material V is the

29、 veiocity of the tape over the head w is the gap width A is the wavelength of the signal on the tape. From this expression it can be seen that the voltage across the coil increases directly as the velocity increases and as the wavelength de- creases ( frequency increases). If the tape velocity and g

30、ap w idch are assumed to be constant, the output voltage from the head is directly pro- portional to the frequency, as long as the wave length on the tape is large compare.cl co the gap width. This results in an output vs. frequency characceristic such as shown in curve A of Fig. 2-4. The voltage do

31、es not continue co rise indefinitely. As electrical losses in the core mate- rial increase, and as the wave-length on the tape approaches the same dimensions as the reproduce head gap, the actual output resembles curve B of Fig. 24. OUTPUT -.-r-.-r-r-r- (d bl I I I . I I I I I I I I I I +25 -+-+-1-1

32、-r- I I I I A I : +20 _ J _ !-l-1-1 I I I I I I I . I I I I I I I +15 -+-+-1- I I . I I I I : +10 -l-!-l-=-.-1 I 1 I I I I +5 -+-c, .-+-tt-J : I I ., B : I CJ I I I I 0 -+-_. _ o -r-+-r-, I : I : I I I -5 -+- -i-+-1- I I G:) I I I I : I I I I I I I -10 _ _, _ _._ -+-+-r-. I I I I I I I I I I I I I I

33、 -15 -i-i-J,-,1 I I I I I I I I I I I I I I -20 -+-+-, I : I I : I : -25 -i-i-J, _ .:. _ +- I I I I I I I I I I I I I I 10 100 l000-IOKC FREOUENCY Fig. 2-4. Output vs. Frequency In order to provide an overall frequency response that is flat ( see Fig. 2-5) an equalization circuit consisting of a ser

34、ies resistance and capacitance is inserted in one of the early stages of the reproduce ampli- fier. This equalizer has a high-frequency droop characteristic ( curve B, Fig. 2-5) which is the inverse of the reproduce head characteristic ( curve A, Fig. 2-5). In order to extend the high-frequency resp

35、onse, additional equalization is included in the record amplifier in the form of a high-frequency boost circuit, designed to compensate for the droop in reproduce head characteristics caused by head core losses; gap losses and recording losses. DECIBELS _ .,. _ -.-.-, PLAYBACK I ! I ! : : + 25 -EQUA

36、LIZATION -1-PLAYBACK 1 ; CURVE I j HEAD . I +20 - -i-r- 1- CHARACTERISTICS t BI I I I +15 -!- 1-l-i!_t! _ J I , I I o t I I I I I I O I I I +10 -t-_ t _ J _ !-+-1 I : I : I ! I I. I I _, t I I +5 -t-r-t-_,-OVERALL -1 I I I,. I RESPONSE I 0 -,.,1-+- -,-i-t- , I C I I I I I . , 1 , I I I I I I I -5 -+

37、-J I I O I I I I I I 0 I I I I : -10 -J,-.-;-i- I . ,., I I I I I -15 _ J _ ,., _ J _ i-1-i-J A: I I I 1 0 50 I I 500 FREQUENCY iOKC Fig. 2-5. Achieving Flat Response Frequency Response 2-5 Ill. Installation and Operation This machine can be operated in either the horizontal or vertical position. In

38、 the carrying case, installation consists only of making up and connecring the required cables ( See Connector in this section) . For studio installations, an adaptor (Catalog No. 9684-1) is available which permits mounting in a standard 19-inch relay rack. The power requirements are 117 volt a-c, 5

39、0 or 60 cps, 0.52 ampere, 61 watts. A name plate on the bottom of the case ad jacenc to the aper- ture for OUTPUT, LINE INPUT and 117 v. a-c indicates the proper line frequency. The line input is an unbalanced bridging input of 100,000 ohms. Any unit connected to the LINE INPUT connector should deli

40、ver a sig- nal of at least 0.5 volt when recording from consolettes, mixers or other tape recorders. The recorder is wired for a high impedance microphone, but pro- vision for internal mounting of an accessory plug-in transformer imme- diately changes the machine for use with low impedance microphon

41、es. To make this conversion, remove the four screws on the panel of the electronics assembly. The panel and assembly can then be removed. A. High Impedance-a dummy plug Jl07P shown on the sche- matic diagram ( Fig. 5.3) muse be plugged into socket JI06S for high impedance op- eration_ B. Low Impedan

42、ce-remove the dummy plug Jl07P. Acces- sory transformer AMPEX catalog number 17331-1 (shown as T103 on schematic dia- gram Fig. 5.3) is then piugged into J106S for impedance in the range of 150 ohms to 250 ohms. C. 30 ohm to 50 ohm-Install transformer T103 as shown on the schematic diagram (Fig. 5.3

43、) by plug- ging the transformer into socket J 106, and removing the jumper as shown in Note 7 on the schematic. The output of the machine should be connected to a unit having 600 ohms input impedance. In a situation wherein the recorder will work into a high impedance line, physically terminate the

44、OUTPUT connec- tor with a 600 ohm resistor and bridge this resistor with the high im- pedance circuit. A three circuit OUTPUT plug is supplied. A cwo circuit plug can be used, and will work; but it automatically makes an unbal- anced line. If an AMPE amplifier loudspeaker is used plug it into the MO

45、NITOR jack only. GENERAL POWER LINE INPUT MICROPHONE INPUT REPRODUCE OUTPUT 3-1 INTERCONNECTING Regardless of application observe the requirements under Line Input and Reproduce Output when interconnecting the machine with any other piece of equipment. 3-2 CONNECTORS A power cable and matching plugs

46、 for the MICROPHONE (101S), LINE INPUT (102S), and OUTPUT (104S) connectors are sup- plied with the equipment. Shielded, low-capacity cable is recommended for making up input and output cables. Make such cables as short as possible for intercon- necting units in audio systems. Refer co the schematic

47、 diagram (Fig. 5.3), to determine correct pin connection for all plugs. STUDIO The reproduce head cabl is double shielded, insuring against r-f INSTALLATION pickup. Cable capacity and length have been minimized to avoid high frequency loss. In general, mount the electronic assembly and tape trans- port no more than one foot apart. If the reproduce head cable is length- en