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Содержание 2619

Страница 1: ...effect transistor preamplifier for the full range of B K microphone cartridges The extremely high input impedance presents virtually no load to the microphone ensuring a flat overall frequency respon...

Страница 2: ...HALF INCH PREAMPLIFIER FOR CONDENSER MICROPHONES TYPE 2619 December 1969...

Страница 3: ...IPTION 6 2 2 Input Characteristics 7 2 3 Output Characteristics 8 2 4 Frequency Characteristics 9 2 5 Gain 9 2 6 Distortion 9 2 7 Noise 11 2 8 Temperature Environment 11 3 OPERATION 12 3 1 Power Suppl...

Страница 4: ...uded are a gooseneck UA 0196 to facilitate measure ments in high temperature 1500 C by taking the preamplifier away from the transducer and for providing directional flexibility for the microphone an...

Страница 5: ...hone It is therefore desirable to reduce this loading as much as possible in order to achieve the highest possible signal to noise ratio Usually the cable capacitance is avoided altogether by screwing...

Страница 6: ...of voltage of only 0 3 dB for a 1 2 microphone The calculated cut off frequency is 2 Hz and this is about the same as the mechanical cut off of the microphone due to the pressure equalization R c R a...

Страница 7: ...ead adaptor for 1 microphone cartridges coaxial input plug adaptor for miniature cables flexible gooseneck extension Adaptors UA 0035 for 1 4 cartridges and UA 0036 for 1 8 cartridges are also availab...

Страница 8: ...ng it a very flexible unit 2 2 INPUT CHARACTERISTICS The input impedance depends on the operating voltage of the preampli fier and on the temperature Input resistance 4 Gn 120 V operation 2 6 Gn 28 V...

Страница 9: ...apacitive current increases with frequency for a given voltage This effect means that distortion can arise at high frequencies when very long cables with high capacitance are connected to the output T...

Страница 10: ...so 10 20 so 2ll so 2ll so 1If 2ll 0 001 0 01 0 1 10 100kHz I 0 O J7 2619 2612 13 mVf Jbar de ty u 2619 Ty 4t33 2614 15 Frtt f ield mlcrophon t J o P _ul lMod 0 Aoft_lft OOftU I 1 90 0 0 2 2 10 20 10 2...

Страница 11: ...5 10 f I II 1 t 1 100PF I 1 50pF 20PF 7 5 8P7 I I I I I I II I I I I I 02 0 5 10 20 Hz 50 Fig 2 5 Typical low Frequency responce I I 1 I I I I I 1 DC Supply 120V 1 4 Distortion i I 1042Hz 5 105 2 11...

Страница 12: ...one end of the preamplifier and prevents condensation in high humidity environments This i automatically connected to the heater supply in ordinary B K microphone input sockets If however the micropho...

Страница 13: ...from a single 28 V supply The connections at the plug are shown in Fig 3 1 Pins 5 and 6 should be connected together for 28 V operation P I ns 5 6 short e d for operat i on trom 2S V only Signal 4 5...

Страница 14: ...rophone artridges can be used with the 2619 except for the piezoelectric microphone 4117 The microphones and their respective adaptors are Microphone Adaptor 1 DB 0375 1 2 No adaptor required 1 4 UA 0...

Страница 15: ...the one used in the calibration is employed it must be remembered that the voltage sensitivity of the new accelerometer cable combination will be different The new sensitivity Sv is given by Sv S C C...

Страница 16: ...r 3 minutes Linear 2 Hz 200 kHz Linearl22 5 Hz 200 kHz A weighted B weighted C weighted Distortion see curve inside Pulse rise time 0 2 Jsec Decay time 0 6 Jsec Temperature range 20 to 60oC Dimensions...

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Страница 18: ...rs Accelerometer Preamplifiers Accelerometer Calibrators Vibration Meters MagnetiC Transducers Capacitive Transducers Vibration Exciter Controls Vibration Programmers Vibration Signal Selectors Mini S...

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