CO-ORDINATOR IMAGE Around STEREOMoveYourSound ACTIVEFILTERS DESIGNING UNIT PROTECTION LOUDSPEAKER CONSTANTS? METER TIME FREQUENCY SPACECRAFT HISTORYOF ...NEWS....PROJECTS....MICROPROCESSORS....AUDIO.. All kits alsO available as separate packs (e g. P.C.B.. component sets, hardware sets, etc.) TRANSCENDENT 2000 Prices in FREE CATALOGUE. SINGLE BOARD SYNTHESIZER LIVE PERFORMANCE SYNTHESIZER DESIGNED BY CONSULTANT TIM ORR (FORMERLY SYNTHESIZER DESIGNER FOR EMS LIMITED) AND FEATURED AS A CONSTRUCTIONAL ARTICLE IN ELECTRONICS TODAY INTERNATIONAL. The TRANSCENDENT 2000 is a 3 octave instrument transposable 2 octaves up or down giving an affective 7 octave range. There is portamento, pitch bending,a VCO with shape and pitch modulation, a VCF with both low and high pass outputs and a separate dynamic sweep control, a noise generator and an ADSR envelope shaper. Thereis also a slow oscillator. a new pitch detector, ADSR repeat, sample and hold, and special circuitry with precision components to ensure tuning stability amongst its many features The kit includes fully finished metalwork, fully assembled solid teak cabinet, filter sweep pedal, professional quality components (all resistors either 2% metal oxide or 'h96 Metal trim!) and it really is complete - right down to the last nut and bolt and last piece of wire! There is even a 1 3A plug in the kit - you need buy absolutely no more parts before plugging in and making great music! Virtually all the components are on the one professional quality fibreglass PCB printed with component locations. All the controls mount directly on the main board, all connections to the board are made with connector plugs and construction is so simple it can be built easily in a few evenings by almost anyone capable of neat soldering! When finished you will possess a synthesizer comparable in performance and quality with ready -built units selling for many times the price! COMPLETE KIT TRANSCENDENT 2000 PIIIIRMAN ONLY £168.50 + VAT! Comprehensive handbook supplied with all complete kits! This fully describes construction and tells you how to set up your synthesizer with nothing more elaborate than a multi -meter and a pair of ears! Cabinet size 24.6" x 15.7" x 4.5" (rear) 3.4" (front) WE'VE MOVED! INCREASED CAPACITY AT OUR BIG NEW FACTORY NEW FACTORY UP! MEANS MANY PRICES DOWN! ALL OTHERS FROZEN! PRICES DOWN! TRANSCENDENT DPX DIGITALLY CONTROLLED, POLYPHONIC, MULTI -VOICE SYNTHESIZER ANOTHER SUPERB DESIGN BY SYNTHESIZER EXPERT TIM ORR - PUBLISHED IN ETI The Transcendent DPX is a really versatile new 5 octave keyboard instrument. There are two audio outputs which can be used simultaneously. On the firstthere is a beautiful harpsichord or reed sound - fully polyphonic, i.e. you can play chords with as many notes as you like. On the second output there is a widerange of different voices, still fully polyphonic. It can be a straightforward piano or i honky tonk piano or even a mixture of the two! Alternatively you can play strings over the whole range of thekeyboard or brass over the whole range of the keyboard or should you prefer - strings on the top of the keyboard and brass at the lower end (the keyboard is electronically split afterthe first two octaves) or vice versa or even a combination of strings and brass sounds simultaneously. And on all voices you can switch in circuitry to make the keyboard touch sensitive! The harder youpress down a key the louder it sounds - just like an acoustic piano. The digitally controlled multiplexed system makes practical touch sensitivity with the complex dynamics law necessary for a highdegree of realism. There is a master volume and tone control, a separate control for the brass sounds and also a vibrato circuit with variable depth control togetherwith a variable delay control so that the vibrato comes in only after waiting a short time after the note is struck for even more realistic string sounds. Cabinet We 36.3" x 15.0" x 5.0" (reer) 3.3" (front) COMPLETE KIT ONLY £299.00 + VAT! To add interest to the sounds and make them more natural there is a chorus/ensemble unit which is a complex phasing system using CCD (chargecoupled device) analogue delay lines. The overall effect of this is similar to that of several acoustic instruments playing the same piece of music. The ensemble circuitry can be switched inwith either strong or mild effects. As the system is based on digital circuitry digital data can be easily taken to and from a computer (for storing and playing back accompanimentswith or without pitch or key change, computer composing etc.. etc.) Although the DPX is an advanced design using a very large amount of circuitry, much of it very sophisticated, the kit is mechanically extremely simplewith excellent access to all the circuit boards which interconnect with multiway connectors, just four of which are removed to separate the keyboard circuitry and the panel circuitry from the main circuitryin the cabinet. The kit includes fully finished metalwork, solid teak cabin., professional quality components (all resistors 2% metal oxide), nuts. bolts, etc., even a 13A plug -you need buy absolutely no more parts before plugging in and making great music! When finished you will possess an instrument comparable in performance and qualitywith ready -built units selling for over £1,200! ORDERING INFORMATION AND MORE KITS POWERTRANINCLUDING THE K,MEtZ HOLE ON PAGE 9 rrru fit DEsIoNING ACTIVEFILTERS PROTECT/ONONAUNiT LOUDSPEAKER TIME CS TNTS ? FREQUENCY METER. FEATURES DIGEST 8Ifit matters it's here. DESIGNING FILTERS 17Do it yourself it's easier! HISTORY OF SPACEFLIGHT 24What goes up.... ANTI -MATTER EXPLAINED 32NOTHING to do with Star Trek DESIGNERS NOTEBOOK 37A flash of LED knowledge. AUDIOPHILE 43Atomic theory amplifier? TIME CONSTANTS 49Have you the capacity for this? MICROFILE 53Sinclair ZX 80 examined. TECH -TIPS 57This is all your fault! RAVEN ON 63News from around the world PROJECTS IMAGE CO-ORDINATOR 68 Moving sound reproduction? PORCH LIGHT 77 Don't be left out in the dark. Image co-ordinating p.68 STATE VARIABLE FILTER 84Two for Project 80 synthesisers. ENVELOPE SHAPER 88 LOUDSPEAKER PROTECTOR 95 Cone preservation device. FREQUENCY METER 99 Linear cycle counter. INFORMATION. A RECORD NEW OFFER 13 Some cheap discs to slip. ETI NEXT ISSUE 15 Next months machinations. ETI SPECIAL OFFER 41 Seek Seikos here. SUBSCRIPTIONS OFFER 61 Buy 1980, get 1999 FREE!! BINDERS 61 Keeping it all together. ETI BOOK SERVICE 81 Fine print indeed. ETIPRINTS 92 No other way is worth it. Quantum sounding off p.43 PCB FOIL PATTERNS 103 Board level decisions. EDITORIAL AND ADVERTISEMENT OFFICE 145 Charing Cross Road, London WC2H OEE. Telephone 01-437 1002/3/4/5 Ron Harris B.Sc. Editor OVERSEAS Ian Graham B.Sc. Assistant Editor EDITIONS Tina Boylan Editorial Assistant Diego M. Rincon Art Director AUSTRALIA : RogerHarrison Dee Camilleri, Enzo Grando, Production Editor Loraine Radmore, Lorraine Stout Paul Edwards, Tony Strakas, Technical Illustrators CANADA : HalvorMoorehead Ray Marston Project Editor Editor John Fitzgerald Project Engineers GERMANY : UdoWittig Steve Ramsahadeo Project Development Editor Christopher Surgenor Group Advertisement Manager Steven Rowe Advertisement Manager HOLLAND : AntonKriegsman Sandie Neville Advertisement Production Editor T.J. Connell Managing Director ABC PUBLISHED BY Modmags Ltd., 145 Charing CrossRoad,WC2 DISTRIBUTED BY Argus Distribution Ltd. (British Isles) Memberof the 12-18 Paul Street, London Audit Bureau Gordon & Gotch Ltd. (Overseas) MODMAGS LTD of Circulation PRINTED BY QB Limited, Colchester Electronics Today International is normally published on the first Friday of the month prior to the cover date. ©MODMAGSLTD.1980 All material is subject to worldwideCopyright protection.All reasonable care is taken in the preparation of the magazine to ensure accuracy but ETI cannot be held responsible for it legally. Where errors do occur a correction will be published as soon as possible afterwards. ETI JULY 1980 3 F2F44,TIggS148M2p$24727.11442$2$F22111WEiRMSAMMMer234254A24221Emmmmmmmmffffr-rJddddNnNNNrvNNnNNNNnNNnNNNnnNNnNNNNNNnNnnhNNn. !th-TD.'nT23999TL'9Dt.TTMT9S"LlT9T,T9'.2.7.2MT.T.1399.2m74,F8=Epmf44ggpsslvgaregmFsuccium?FL6F,FFggp2gggag2r88812AMTAL=TOru,,2SG,O23,10132,614;gRIgng-N.. VM1:22AMNR4g4r2FAVITVXXXXAM22FFPARF 1.122p=ngF.14g,'pOmpRREERREURRRERREREURRAAggwg,WAAAAARURMILW4gUndiagaa§00000--"n:IR4FgRsp.4.nramg4.-4,;gtg26,p,n,;;ggsAmilgggA4p2R2EAgms,.2vg2,42g*,7F2r,4g.Tpnig,A2248$2t4 R§CUPAR$C4FAR2232%N=144;$2M32:=22Grall"VORP.22Ig3285iV;2XLSV4,744-WWSPFSS:IFFFIW/222:erMAAAASSRI:See012.722mt0"g P4422=;rn-A21.-41.83§23829.;=94:=IgqigNq99D99DS'D999D99_, ry =.21204-gopUFSP,''' ""X: UVaiiFa??M*H4WIWAURREF4AggigggriAa;!2112,7,1,,,Isivg,s2Aga4T4,8,.2HRMAUEE: §RMWRIMMUIriaAiggWOR''''' 24:=39=MA eaRRRURRURRURRUHRREARRURAiAggFmmaggnnnnnn g"sguspliv.,'nnnnN '' ::::""2:148smmIsmme:sfuggifp X3X2A2r,MAPAAggg=g7"14A4APAAAgAgMAP421A2.1:4MLT61,FEX6FFFSS322,12g2XAA:2=12222221888888g88888888888888888574,9.=4;1'=;32e9-^5A81WWMIXAXPi.l!HE2FAIR4442gg8;g18WARAAni§WilVRMA:SSXAMMS*MgASISF2SSASSMN2V2SR2MME414=4183$1$$$WAXS---------- ''''' ------ "'""-sUUWUWM4alIMPAWMUMTRWWWWW=4;;;;;:===alimMIU-umiF§AnxdiFAFEF,EFIF3"jF"r4:31!_qq12!-IFFIEa-"""mS4P,MTAA2.7,A2MAgR3=AR2 iMMMIEEEEEIVIIMMFaiVligiiiii1=3=P1M2Walrilggahltra=V;IgAT27M.7.22,7,18=2;SSIR;ARP9,PRIM-i*Woo""" ----- "PAAXI""0"2"'SF4:12RARARRFFS!!22,91,9.22FRXM2rAgIRAAgM;VVV!EOE41182861FilgHgnPWw4W45MhigivaazEFTT!!::::::!ffT!!!ffLgg0 .88Pgggig (0)<(7'144.1,9P.A4AA22224222A4442222g=242"00"-Mi0e000E000A-000-000000000:0triO