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Page 1: ...Radio Com LSM 10 Line Selector Monitor Technical Manual P_A_C_I F_I_C_ R_E_c _o _ R _C_E_R_S_ _E_N_G_I_N_E_E_R_I_N_G_c_o_R_P_O_ R _A_ T_I_O_N __ 2070 Las Palmas Drive C a r lsb ad CA 9 2008 619 43 8 391 1 Telex 181777 ...
Page 2: ...www SteamPoweredRadio Com I ii 2 3 4 5 ...
Page 3: ...UT1 o O S8B TAPEOUT 1 TAPEINPUT2 o o S9A S9B 0 0 TAPE OUT 2 S10A TAPEINPUT3 o o S10B o C o TAPEOUT3 INTERLOCKS IMONITOR I OUTPUT NOTES 1 Left Channel only is show TAPE1 2 Control TAPE 2 3 Power supply not shown TAPE 3 o MONITOR OUT 4 Wilen a Tape Input is choS8f tl e correspon ding T ape Output line is opened ______L _S _ M _ l_ 0 _TE _ C _ HNI _ C _AL __ SP _E _C _IFI _ C _ A _ TI _O _N _S _ ____...
Page 4: ...www SteamPoweredRadio Com LSM 10 Line Selector Monitor Pacific Recorders Engineer ing Corpor ation 2070 Las Palmas Dr i ve Carlsbad California 92008 June 1983 ...
Page 5: ...king 4 2 location 4 3 Input Connections 4 4 Output Connections 4 5 Power Connections 4 6 Meter Zero 5 Operation 5 1 Introduction 5 2 Non Tape Inputs 5 3 Tape Inputs 5 4 Monitoring 5 5 Metering 6 Technical Description 6 1 Program Amplifier 6 2 Monitoring Amplifier 6 3 Metering Amplifier 6 4 Power Supply 7 Drawings ...
Page 6: ...at when a tape machine is selected as the source the output l ine to that tape recorder is interrupted preventing the possibility of feedback The program amplifier has a front panel gain trim control The mnitoring amplifier with headphone driving capabil ity allows oonitoring of the output of any of the three tape machines or of the program amplifier all independent of the source selector switch T...
Page 7: ...ifier 8 dBu nominal clip point is 29 dBm into 600 ohm load Monitor amplifier 8 dBu nominal clip point is 21 dBm into 600 ohm load Program amplifier less than 100 ohms balanced floating transformer coupled Monitor amplifier less than 40 ohms unbalanced Output Load Impedance 600 ohms or greater Frequency Response o 0 6 dB 20 Hz to 20 kHz Signal to Noise Ratio Better than 90 dB with 8 dBu test tone 2...
Page 8: ...esponds to an amplitude of 0 775 V RMS regardless of impedance It is the same as O dBm if the impedance of the circuit under discussion is 600 ohms It may be considered O dBm enabling convenient measurement with meters calibrated for a 600 ohm circuit if the circuit impedance is simply disregarded 3 The program amplifier and metering amplifiers in the LSM 10 have adjustable gain enabling operation...
Page 9: ...ent provided by the other manufacturer C The warranty period on equipment or parts repaired or replaced under warranty shall expire upon the expiration of the period of the original w arranty D This warranty is void for equipment which has been subject to abuse improper installation improper application improper or omitted maintenance alteration accident negligence in use storage transportation or...
Page 10: ...etween rails which have been grounded if that option exists The unit should be located at the operator s position in the recording or production facility The VU meters should be clearly visible and the source selector switch should be conveniently close 4 3 Input Connections The input signals applied to the LSM 10 should be applied from a source of 600 ohms or less The level should be about 8 dBu ...
Page 11: ...m the m nitor amplifier is continuously adjustable in level up to a maximum of 21 dBm into a 600 ohm load The internal impedance seen looking back into the avnitor amplifier is about 40 ohms the load should be 600 ohms or higher The monitor amplifier output is unbalanced and appears at the front panel headphone jack Should this jack be unused then that output signal is normalled through to the mon...
Page 12: ...tact For safety reasons this pin is connected to the chassis of the LSM 10 directly D not sever this pin do not sever t he gr een wire in the power cord at either end and do not use an adaptor t o enable the three prong connector to plug into an older style two prong outlet 4 6 Meter Zero Prior to actually applying power check the VU meter mechanical zero adjustments If necessary zero the meters w...
Page 13: ...ront panel gain trim adjustment which allows as much as 25 dB of gain t o be added to the input signal 5 2 Non Tape loputs The LSM 10 accommodates a total of ten inputs three of these are set aside specifically but not exclusively for tape recorder application and are handled internally in a manner sli ghtly different from the remaining non tape inputs The non tape inputs which might be for exampl...
Page 14: ...cted is determined by the INPUT switch The selected source drives the program amplifier Should its level be low it can be increased by operating the GAIN control The selected signal will appear simultaneously at the main output connector and at the auxiliary output connector In addition it will appear at the inputs to the other two tape machines useful for dubbing The tape signals can be DX nitore...
Page 15: ... as being the proper tape prior t o using it as a program source 5 5 Metering The metering system in the LSM 10 includes buffer amplifiers so that the meter rectifiers do not add distortion to the audio signals The meters can be switched by using t he METER switch to read either the chosen input signal level or the output of t he program amplifier 6 TECHNI CAL DESCRIPTION In the following discussi...
Page 16: ...o both the main and the auxiliary output connectors 6 2 Monitor Amplifier The monitor amplifier is a dual type for stereo Only the left channel will be discussed The s i gnal to be monitored as selected by the MONITOR selector switch is applied to an input differential amplifier using both halves of U3 R21 and R25 with Cl9 and C20 provide RF bypassing Cl8 and C2 1 remove any DC component from the ...
Page 17: ...tection to the meter 6 4 Power Supply The LSM 10 can be operated from either 120 or from 240 VAC at either 50 or 60 Hz Operation from 120 VAC is accomplished by connecting the power transformer primaries in parallel while operation from 240 VAC is accomplished by connecting the primaries in series Refer to Figur e 4 for the connections The transformer output is rectified by full wave rectifier BRl...
Page 18: ...S88 TAPEOLIIT1 S98 TAPE OUT 2 S108 TAPE INPUT3 o __ lll tl 0 o TAPE OUT 3 INTERLOCKS OUTPUT TAPE1 TAPE2 TAPE3 IMONITOR I LEVEL MONITOR HEADPHONE p MONITO I OUT NOTES 1 Left Channel only is shown 2 I PANEL IControl 3 Power supply not shown 4 When a Tape Input is chosen the correspon ding Tape Output Line is opened FIG 1 LSM 1 O FUNCTIONAL BLOCK DIAGRAM ...
Page 19: ...H I UNLESS O ERWl5E SPE CIF IED _LL AE ISTORS AQ 11n1 5 AL CAPACITATOR AAE l E _5VRE O II l IICRO F ARA05 NOTCS BR Ti J 12J A 1101 J 123 A ORANG ORAIJGf VIOU T CRAY JZS I z LMl 1 LlO I 4 HI I LO J 9 r L Ml 4t L LO I 4 I NI I __ _ _ _ _ R LO AUXILIARY OUTPUT LEFT RIGHT Jl7 1 r J HI 1 l LO 1 l VllO TO lNPUT SEUCTOR SIAIITCHfS TO MONITOR ANO METER 1 SELECTOR SWITC HfS S LO 5HU R16HT MAIN OUTPUT Ji4 1...
Page 20: ...l 101 1 I pr FIJ l 1 I 11 j 4 Cl Z j Fl l O I 101 1 4 Rl l 101 1 cu A ll R1z I0K Rl3S IOK I Cl IJ IOOpF V A 1 Rl34 101 I C l Z lo 11 Op l ztO Z 1K G2 MJE 131 C lr Z l CR5 lt41 11 1 C39 4 1 n MONITOR RH R45 VOLIJME 4 C40 4 ln 101 Z Z c1 n IC I c I I Q4 l J 111 RIii Z 111 I NITOR oom T7 I I r z lO LEn I I I I I J WI I I I I I I I I I I I I 1 5 1 0 lelfT I S M _ _J Rl O t 114 Q 11 MJIE 161 C131 LIO t...
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Page 22: ...LO T e LEFT Lu I INPUT C I JC LEFT HI 4 Rl6HT HIELO Tl Y o RIC Hl HI LEFT HIE LO Rl6Hl LO LE F T LO 3 LEfl HI I 4 Rl6HT IUElO PCA 91 l CONTINU D TAPE 1 1 LEF1 5HIELD G Rl6HT HI I E IZ I LEF1 HIEl0 I I L El 5 _ RIC lT LO E I 2 LEFT LO R 16 1 1 1 5HIELO LEn HI z LEF1 LO lo R16Hl HI PZI I G I 5 I 8 11 5 PZ EIZ I E I I EIZ En I 4 2 I lei J2 _ I_ 5 Rl6Hl LO OUTPUT LEFl SHIELD R16Hl SHIELD LEFT HI I RIC...
