Sparta AS -30B Technical Manual Download Page 1

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Summary of Contents for AS -30B

Page 1: ...www SteamPoweredRadio Com SPARTA AS 30B AUDIO CO SOL TECH CAL 1 AN AL...

Page 2: ...ones 1 mw nomina l into lOK ohms FREQ RESPONSE All outputs less than 2db down 20 Hz to 20 kHz NOISE DISTORTION C Ra3STALK POWER SIZE SHIPPING WT MUTING NOTE 1 NOTE 2 Below 65 db a t 0 vu out with 55 d...

Page 3: ...ight be of greater service your suggestions will be greatly appreciated AS 308 Customer U _ v liv u L l rp SERIAL NO _ J_______ _f_ ___DATE r 4 1 r 1 PWR SUP SERIAL NO VJ j 7 CAL BY 2 U Q No OF PREAMP...

Page 4: ...sources intended for single ended high impedance loads the minus input terminals of the consoles are connected to the shield and the console now appears as a single ended high impedance l0K load T he...

Page 5: ...7 stranded or 8739 solid Either may be used although it is generally more satisfactory to use solid wire in a permanent installation where flexibility is not r equired since solid wire is easier to ha...

Page 6: ...0 to Jf dbm depending of course on the sound level and microphone used In a norma l s ituation then the preamplifier output is at essentially the same level as the high level input signals resulting i...

Page 7: ...nals via the input cables Mixing ta kes place by feeding the output of each mixer potentiometer through a high value series resistor l0K or 27K to a common mixing bus which in turn leads to a mixing a...

Page 8: ...program to substanUally the same level as originally fed to the mixer pots with the mixer pots at their usual operating positions about one o clock Since a current mixer operates from a relative ly h...

Page 9: ...ut transformer must be isolated from the line with a pad typica lly 4 db to prevent interaction with line reactances Finally the line amplifier output impedance must properly match the line transforme...

Page 10: ...e is the line transformer output ahead of thG line pad which al lows an added 4 db of attenuation in the meter pad for increased i solation A balanced H pad i s not required since the meter need not b...

Page 11: ...Dr SCJUPrION GENERAL stage of the progrum line amplifier Since there are no active or non linear components to follow the monitor provides constant assurance of both level and quality whereas the VU m...

Page 12: ...and excellent overload churacteristics With normal microphone input levels the output level to the mixer will be approx 0 dbm The maximum output level of the 1018 before clipping is in excess of 14 d...

Page 13: ...he feed ba ck to the emitter of Ql is in pha se with the signal input to the base of Ql This consitutcs negative feed back since the feed back attempts to cancel the input signal The open loop gain wi...

Page 14: ...tter voltage of Q3 is set by the collectcir voltage of Q2 and since the collector current of Q2 is also the emitter current of Q2 any change in the coJlect or voltage of Q2 also ppears as an inverted...

Page 15: ...the supply or towards ground If the operating point is beyond the limit given but still capable of moving further in either direction t he amplifier will still be operative it simply will not have as...

Page 16: ...ers t hrough high value resistors of lOK ohms or more Each input current t hen follows the path of least resistance into the mixer amplifier independent of the condition of the other mixing chan nels...

Page 17: ...tor vo_ltage R3 then forms a negative feedback path which assures that Q l s operating point remains within a reasonable range Normal operation of Ql will be obtained at any collector voltage between...

Page 18: ...gh a resistor R7 which is ten times larger than RB so it must cause ten imes the voltage change The voltage gain of Q2 then must simply be the ratio of R7 to RS or ten In normal application Q2 i s loa...

Page 19: ...n only rise to the point where t he combined foedback currents from R3 and R6 approach cancella tion of the input current with bthc current through R6 being dominant Very low distortion results typica...

Page 20: ...s compared to the input signal at the base of Q3 thereby s etting the ac gain When power is first a pplied Cl3 must be charged to one half of the supply voltage through Q6 and to protect Q6 the chargi...

Page 21: ...ill change due to the rising reuctance of Cl3 This change will appear as an error signal when compared with the input and allows the reserve open loop gc1in of the ampliher to correct the error thereb...

Page 22: ...ood match for the 60 ohm primary of the line output transformer The transformer produces 10 db of voltage gain which is followed by a 3 db loss in a resistive isola tion pad The rms signa l volta ge a...

Page 23: ...uld be most suspect since subsequent gain i s the highest Hum 120 Hz would of course lead one to the power supply Distortion will be practically non existent if norma l de a nd ac gain is obtained The...

Page 24: ...s carry an extended warranty of 50 of the replacement cost being allowed should failure occur during the second yeur Electron tubes und sHicon rectifier s bear only the wa rranty of the ma nufacturcr...

Page 25: ...1001 C 4 I 1000pf T 201 GND 1003A 5 1018 2 5 3 1 4 2 5 6 6 FUNCTION IN PUT INPUT GNO GN0 i c OUT PU r 6 R9 180 c I 501 RIO 3 9K C 5 l 000pf 20VOC 03 R2 680 C6 I 5 l 25 C 7 50 V t I RS I M 5 6K Rll 1...

Page 26: ...KR 177 15 JVLY O E R 14 1 W 16 tll3S S 1tr 1 n0 ts GH 7o CC 7 RS 2 70 J 3 2 TO MAST ER OAIN CO iT llOl R9 1 20 Rl3 151 C9 33n CIO E B pF Q S 2N33 88 Qt 2N40 6 27 V RIO l SOI Q4 R20 1 5 C J I R22 51 J...

Page 27: ...www SteamPoweredRadio Com 4 7 K 1 8 K Input 3 3 K vu Al I r esistors 1 W 5 SPA RTA EL ECTRONIC CO RP 905 METER PhD Drown 1 C h k J I C c te Rc v i std f rr b I t o I s 2 3 I smv I I I 11 20 69 t...

Page 28: ...R6 1 K R7 4 71 RS 10 J 7 _ 3 DC E I l I 1 SENSE I Gr _l_ cs 35 T 2 SENSE p l o __ 1 4 DC Output 28 VDC DC volts f to 9 buss Re s i t ors w 10 Copocitors in mi d ECR 1861 odd connect no 103 SOARD r _...

Page 29: ...Brn l t ij Grn I j 1 1 I t I I _I I B k 1 c_ _ NC t 1 2 K Wlj l I I I 62 62 3 2 L Yel 1 I V 0 7 11 L 1 LINE OUT 4 c 1 6 10 GND Primary 60ohm Secondary 600 ohm ldb 20Hz to20KHz at 24dbm Resistors tw 5...

Page 30: ...O OPTIONAL 620 ohm TERMINATION RESISTOR USE WITH lOK BRIDGING TRANSFORMER ONLY TERMINATING RESISTOR 620 ohms REQUIRED WITH 600 ohm TRANSFORMER ONLY __ M _ u 9 MIXER POTENTIOMETER 7 COMMON GND SPARTA E...

Page 31: ...www SteamPoweredRadio Com JJ...

Page 32: ...www SteamPoweredRadio Com 1 C II t u 0 1 v 7 _ fll J t c J AS O B AUDIO C Ot 0L 5 1 09 c...

Page 33: ...llowed yet RFI does occur in even the best of installations necause of its virtually unpredictable nature It does not necessarily require a strong field for RF to result and it is not uncommon for an...

Page 34: ...l still exist simply because there is no way to force a component such as a semiconductor to recognize the difference between a change of voltage or current at audio frequencies and a similar or great...

Page 35: ...am or again the silence of a blocked amplifier stage If the offender is a VHF FM carrier however it will most often be entering the audio system via a conductor or cable that is resonant or 11 tuned a...

Page 36: ...tors fqr RF and that any wire or metal structure will be resonant at many different frequenci es The most prevalent example of course is the twisted pair shielded audio cable feeding a console which m...

Page 37: ...ic fields There is no hard and fast rule hmvever and it is wise to try various combinations When the interference is in the VHF range it will often be found that shortening QL l engthening a cable wil...

Page 38: ...e reciprocal relationship if the audio line impedance is higher the capacitor should be proportionally smaller and visa versa In severe circumstances RF chokes may be inserted in series wit the audio...

Page 39: ...s of RF detection resulting from point contact of two dissimilar metals The significant factor is that a junction of any two dissimilar metals or metal compounds is potential detector Now we cannot pr...

Page 40: ...the AM component along with normal program A sufficiently high level of RF however could completely block a transistor causing complete loss of any audible sympt om so it becomes quite necessary to al...

Page 41: ...ce most audio equipment designs include equivalent suppression at the most likely points of RF detection We can conclude that RF is always a possibility in an audio system and can appear unexpectedly...

Page 42: ...modification to the knob is necessary and your Colordots made of heavy acetate will last for years Since Colordots are transpare t a code or reference can be incorporated underneath which will be cle...

Page 43: ...21 5 178 298 437 6 219 338 457 7 238 338 457 CRIMPED LEAD VERSION ONLY MARKING CODE TABLE 4 CAPACITANCE MFDS WORKING VOLTAGE COLOR CAP 1ST SIGNIFICANT NUMBER RING 2ND SIGNIFICANT NUMBER DOT MULTIPLIER...

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Sparta AS -30B, Technical Manual

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