Ampex-385-Operation-Maintenance 电路图 维修手册.pdf

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1、!PlIEX MODEL 385 OPERATION AND MAINTENANCE MANUAL I MODEL 385 1!-JSTRUCTION MANUAL FOR AMOEX MODEL 385 THREE CHANNEL MIXER The Ampex Model 385 Three Channel Mixer has been designed to mix three low impedance microphone input sources to feed the input of the Bridging Meter Control Panel on the Ampex

2、Model 300 Magnetic Tape Recorder. Sufficient amplification is provided before mixing to insure the highest possible signal-to-noise ratio and to allow the use of untermin- ated inputs . SPECIFICATIONS Inputs: Three microphone level inputs incorporating high level mixing. Shipped for 2.00 to 250 ohm

3、impedance non-terminating. Can be strapped for 50 ohm, 125 to 1 SO ohm, and 500 to 600 ohm. Output: Cathode follower output (unbalanced) designed to feed only the Briclging Input Meter Panels of the Model 300 Magnetic Tape Recorder , Gain: Sufficient to produce the recommended operating level on the

4、 ta pe with an input signal of -94 dbm, on any channel, (Mixer level controls and Meter l?anel Level control set for zero db attenuationJ Frequency Response: t l db 30 to 15,000 cycles. No is e : 6 5 db be low signal for input s of -50 dbm. This repre- sents a noise equivalent to an input signal of

5、-115 dbm. Distortion: With a -SO cl:b_mtinput signal and sufficient gain to modulate the tape 15 db above the recommended op:rating level, distortion is 2% RMS total harmonic on a 400 cycle tone, Control s : Three 20 step attenuators (2 db per step tapered to infinity) a.re used as high level mixing

6、 controls. The record level control on the Mete r Control Panel of the recorder functions as the master gain control. An External Line Key provides for switching the tape recorder to an external line, Tubes: 5 l 6J7 Vacuum Tubes 6C5 Vacuum Tube Power Requirements: l.8amperesatl6.3volts, ac, and 10 m

7、iltiamperes at 390 volts , de, obtained from Electronic Assembly of the Model 300 Magnetic Tape Recorder. MODEL 385 -Page 1 6-23-52 I Dimensions: For rack mounting standardl9wi,cepanel - commercial notching - 7 inches high, Can be mounted in portable case of the Ampex Model 300 Tape Recorder. W e i

8、g h t : 18 pounds. INSTALLATION WITH MODEL 300 .RECORDERS I. POWER Connect the Power Cable from the Power Supply Connector, Jl905P, to the Remote Power Connector on the Electronic Chassis of the .Model 300 Tape Recorder. The Meter Control Panel Power Cable should be inserted in the Meter Panel Conne

9、ctor, Jl904S, on the Mixer. II. OUTPUT Connect the Mixer Output Cable from terminals l, 2 and 3 on Mixer Terminal Strip, TS-1901, to termina ls 1, 2 and 3 respectively on the Bridging Meter Control Panel. The cable shield connects to terminal 3 (ground). The externa l line connections are 4, 5 and 6

10、 on Terminal Strip 190 l and become the input to the tape recorder when the Line Key is thrown, Terminal 4 should be strapped to Terminal 6 (Ground) for un- balanced operation. III. INUTS The three m icrophone inputs are normally strapped or 200 to 250 ohm source impedance. For other impedances see

11、Note 1 on the schematic dia- gram. Pins land Z on the lnput Connectors are the microphone line in, The microphone cable shield should be connected to pin 3 (ground), Certain types of microphones may require resistive loacling, In such cases, the recommended termination should be wired across the Inp

12、ut Connectors and the transformers strapped for the proper impedance. IV. HEATER BALANCE ADJUSTMENT The Heater Balance r.otentiometer, Rl9Z7, is provicled for balancing 60 cycle hum. lt is adjus ted a t the factory and normally will not require readjustment, Some tubes require deHcate balance of thi

13、s potentiometer and even in balance may produce excessive hum. These tubes should be discarded, NOTE: This mixer is subject to RF pickup in strong fields and should not be used in dose proximity to broadcast. transmitters. MODEL 385 Page 2 6-23-52 I Schematic Ref. No. A-1901 C-1901 C-1902 C-l 903 C-

14、1904 C-1905 C-1906 C-1907 C-1908 C-1909 C-1910 C-1911 C-1912 C-1913 C-1914 C-1915 C-1916 C-19 17 J-1901S J-1902S J-1903S J-1904S J-l 905P R-1901 R-1902 R-1903 R-1904 R-1905 R-1906 R-1907 R-1908 R-1909 R-1910 R-1911 R-1912 REPLACEMENT .!,RTS I 1ST MODE L 385 THREE CHANNEL MIXER De-s.c ription Ampex C

15、atalog No. 6-8 V. Panel Lamp -Bayonet Base LA- 5 Pilot Lamp Base DL- 3 50 MFD, 25 V. Electrolytic Condenser CO-60 50 MFD, 25 V. Electrolytic Condenser CO-60 50 MFD, 25 V. Electrolytic Condenser CO-60 4 MFD, 450 V. E lectrolytic Condenser CO-54 !hMFD, 450 V. Electrolytic Condenser CO-54 4 MFD, 450 V.

16、 Electrolytic Condenser CO-54 1 MFD, 400 V. Oil Condenser CO-40 1 MFD, 400 V. Oil Condenser CO-40 , l MFD, 400 V. Oil Condenser CO-40 25 MF D, 400 V. Oil Condense r CO-41 50 MFD, 25 V. Electrolytic Condenser CO-60 4 MFD, 450 V. Electrolytic Conde nser CO-54 . l MFD, 400 V. Oil Condenser CO-40 50 MFD

17、, 25 V. Electrolytic Condenser CO-60 . l MFD, 400 V. Oil Condenser C0-40 2 MFD, 600 V. Oil Condenser CO-49 4 x 20 MFD, 450 V. Electrolytic Condenser CO-65 Microphone Connector Cannon P-3-13 PL-111S Microphone Connector Cannon P-3-13 ?L-111S Microphone Connector Cannon ?-3-13 PL-1115 Power Connector

18、Jones S-308AB PL-54S ?ower Connector Jones P - 308AB 2700 OHMS, l Watt Composition .Resistor 2700 OHMS, 1 Watt Composition Resistor 2700 OHMS, l Watt Composition Resistor 1 Megohm, l Watt Composition Resistor 1 Megohm, l Watt Composition Resistor 1 Megohm, l Watt Composition Resistor 300,000 OHMS, 1

19、/2 Watt Wi.rewound Resistor 1% 300,000 OHMS, 1/2 Watt Wirewound Resistor 1% 300,000 OHMS, 1/2 Watt Wirewound Resistor 1% 250,000 OHMS, 20 Step Potentiometer 250, ooo OHMS, 20 Step Potentiometer 250,000 OHMS, 20 Stt:p Potentiometer MODEL 385 -Page 3 6-23-52 PL-SP RE-8 RE-8 RE-8 RE-32 RE-32 RE-32 RE-5

20、2 RE-52 RE-52 RE.237 RE-237 RE-237 I n 101.Jrt0Z,Tlf ttOltlfALL.Y STRAPP0 n)lt WO TO z, o Oltll.S FM OTHU tW0.Mt-P-;-;o.i,-.JV.N-.-+,.,. lllto,l,P,l,( t! lfS 011 MFO. J. -.I. R($t$fOJI:, AJtl I WA,l t 10%. l.lM,.(SS OfPlUl-wlSE SP(C1Fr0, , WOf.TAGf:S Jli!l(.Utllt(O WITI Z0.000 OMNI P(lt IO:r MCU. . ,.n IW MIXER PRE-AMPLIFIER : .: . z :, . MODEL 385 0 . . . . ., ., AMPEX CORPORATION I . 1 2 3 REDWOOD C1TY, CAUFORlf1.t, J1.o, - TO YCTCR ,.,.CL TO suPt.( -