x0xb0x fab manual
Contents
1. Testing The headphone amp is best tested at the end once all the jumpers are attached Parts D32 1N4148 D33 100 ohm 590 R 136 resistor C45 eiee CA CA U OO A E Oa CA CA N QQ CA pP w A Oo KK o 00 M M M M M Q33 1 Q34 FIN aa 5 V ON S gm Z LA4140 9 SIP 1 IC14 xOxbOx fabrication manual IO Nm last edited May 10 2005 Board Introduction In this section the entire IO board is soldered together and the USB is tested Be sure to follow the instructions for how to solder in the surface mount USB chip You are here Testing and soldering order IT you are concerned that you will not be able to solder the USB chip we are offering as an extra service to prebuild amp test USB Just make sure you reguest it when you order your kit Since the USB chip 1s the most difficult part to solder this should be done first so that there is plenty of space to work in There are a few techniques for soldering SMD parts The two I am a fan of are either 1 Soldering with silver solder as carefully as possible and then using solder wick to clean up 2 Soldering with solder paste and then using solder wick to clean up There are a bunch of tutorial sites on this just search on google e The SMD tutorial from SILabs just the part about adding parts e Kevin Ros tutorial Here s a straightforward method2. er ee LARLLLLAEARUNDRHNENNAF MM IAS SAN ON E ef Il Pug Ag IS r HB Ha A M obs r prz zB val acu Fa i 1 II S rj LB im E ads sb BM p EI 3 TELL AE u HI x saad did FAZIE IE LL 144444444114 Mm D a 00 LEN a EE N erat BE FT F d p Before top of uad La i Ai t i 7 C oe oe AEK E F a fa TEU TEG x Sletetetetetetemelele s E WR Em EE EDS ET bi After top of mainboard Notes Make sure you dont confuse the two types of serial parallel converter chips Also put in the LEDs correctly or they wont light up the flat side of the LED goes with the flat side of the picture The LEDs use standoffs the EEPROM and microcontroller are socketed a ow PI E To get the LEDs seated best use something like a screwdriver to kink the leads twist firmly between both leads while pressing down on the LED into the board Before soldering the 5 pins of the rotary switches they need to be secured amp centered onto their silkscreen outline Use bare wire to staple the switches down After soldering both ends but before clipping off the excess pull on the wire while heating one end at a time to make a snug fit Don t forget about the two wire jumpers J1 and J2 They are seperate from the wires used to hold down the rotary switches above There are a lot of 10K resistors LEDs and switches It might be
3. best to solder them in that order although you should do whichever is best for your soldering iron and setup Basically just think about what would be the easiest way to solder so that you dont melt the switches when soldering the other parts Parts De DIP n C3 socket pri DIP n Ic socket Rotary encoder 1 S2 16 position rotary switch 2 S3 S4 Solid gauge gt Hn p wire jumpers Solid gauge SI wire straps S4 Tact switch 231183 S27 Ai LEDI Red 5mm LED 40 LED40 _ 0 22 LED 40 LEDI standoff LEDAO ea N44 I 2 2 ceramic 74AC126 1 C103 luF 104 io C104 3 IC16 NE 74AC165 3 An 74AC595 IC4 IC8 xOxbOx fabrication manual T s A last edited May 10 2005 Finishing up You are here teil jie Track e 10 Steps 1 Split the 6 conductor jumpers Make a black mark on the unmarked side of the Jumper using a marker the carefully cut down the center with a knife 2 Solder all of the jumper wires desolder the 3 wires you put in for power earlier or leave them in if they re pretty short Make sure to match up pin 1 of the jumpers with the black stripe on both ends Lat a ADEM III 3 Snapon the switchcaps Attach the standoffs from below using the phillips head machine screws and 4 40 lock washers The shorter standoffs go in the 4 corner holes i i i a Al MI 4 Finis
4. the jumper wire You ll remove these 3 wires at the end and replace them with the grey jumper Heat sink TO 220 IC20 2 2mm power jack POWER 1N4001 D40 D43 1N4148 D44 D47 100 ohm 5 resistor RI 1K 5 resistor 1 8K 590 resistor R179 2 2K 5 resistor R178 6 8K 596 resistor 3 2 4K 1 resistor red yellow black brown brown 5 5 6K 1 resistor 4 ET 2K 202 trim potentiometer TM6 C1 C2 C4 C6 luF 104 ceramic capacitor Do OuF electrolytic capacitor C60 C61 EN 100uF 25V electrolytic capacitor C7 C8 2200uF electolytic capacitor C3 C5 o0 AN65628 DIPdualOp Amp 1IC23 00 CI e 78 06 6V 78L06 6V voltage regulator regulator IC21 Coco 5 0 5V voltage 1022 reference xOxbOx fabrication manual vco H Introduction The first section of the main board to be assembled is the VCO voltage controlled oscillator This section converts a logarithmic voltage into a scaled oscillation The relationship between the voltage and oscillation is called 1 V octave because every 1V increase corresponds to a 1 octave increase in sound For example low C 65 4Hz is generated by 2 0V middle C 130 8Hz is generated by 3 0V and high C is generated by 4 0V You are here After The completed VCO connected to the power supply The jumper wire should be replaced with plain wire Notes e he be sure not to confu
5. the part from constant un plugging and that the voltage across each large capacitor 1s 2 Verify that the voltage between the middle pin for the placement of IC20 large 7805 and the left pin next to the white dot is positive and is higher than 8VDC 3 The 7805 and heatsink need breathing room so bend the IC backwards a bit so it juts out beyond the PCB before soldering it See picture above Solder in IC20 attach the heat sink by sliding it on it should fit snugly Solder in luF capacitors C4 and C6 Verify that the voltage across C6 about 5VDC no RE than 4 5V no more than 5 5V Ua 7 4 Solder in the 7806 IC21 luF capacitors C1 and C2 Verify the votage across C1 is approx 6VDC no less than 5V no more than 7V 5 Solder in the rest of the components Verify that the voltage at pin 43 J4 is around 12VDC or IV 6 The voltage at pin 1 of J4 should be 5 333V which is the tuning voltage and therefore must be as precise as possible This voltage is set by the trim potentiometer TM6 which you should adjust in order to make 5 333V To test the rest of the kit solder three wires from J4 to J4 on the main board making sure to match pin 1 on both sides J4 passes 5 333V and 12V to the mainboard for the analog section In some of the pictures J4 is soldered with the jumper wire Unfortunately the jumper wire 1s too delicate to be soldered in while the boards are still being worked on so don t solder in
6. 17 NPN transistor Q18 O19 O20 023 2SC2291 5 SIP matched pair with 1 O22 common base 2SC1583 5 SIP matched pair with 2 QI2 021 common emitter history xOxb0x fabrication manual last edited May 10 2005 Envelope You are here Testing The only thing that can really be tested is the gating circuit 1 Power up the main board by connecting J4 as before 2 Clip one en I u d of an alligator clip to the south side of R146 gate w We ET q m i k FF gs di EN 3 Connect the other end to the exposed side of R10 on the IO board which provides 5V m a 4 Check the voltage at D35 using a scope or meter When the clip is connected there should be 12V When its not connected there should be 0V LE We en 71 4 hi TII Gy a a LA A A E LL 1 n a cub a F 13 X CE s ae aT M 1 4 Cx FERRER la ML ka Ta So h L 1 La E Md M 5 Check the voltage at D36 When the clip from R146 1s disconnected and touched to R10 again there should be a brief pulse to 12V 1f your meter has a max hold setting you can use this to see whether there is a pulse Parts 1N4148 100 ohm 5 R152 resistor R138 1Meg A log dual 1 VR6 potentiometer 2SK30JFET 1 039 xOxb0x fabrication manual Hob VCA last edited May 9 2005 You are here Notes The VCA can either use the BA662 or BA6110 ch
7. for soldering this chip using solder amp wick The magnifying glass comes in very very handy here Its essential to check for bridged pins and unconnected pins 1 If you have flux spread some on the pads this will help bridging The solder mask should also help a lot E 2 Place a small amount of solder on a corner pad 3 Using tweezers position the chip correctly the circle on the picture matches the circle indent on the chip and heat the corner pad When the soldered pad is heated up align the chip in the right location then pull the soldering iron away B of 4 Place a small amount of solder on the iron tip Tack the opposite corner holding the chip steady with the tweezers METEL mn JM a e 5 A D O HWY Fr As carefully as possible solder the remaining pins Heat where the pin and pad meet then guickly touch some solder to the pin the solder should flow down to the pad o o Y TA TA 8 When you re done look at the board under a magnifier or hold up to the light at an angle to see all the pins un a E Ti J na m m 9 d ma EB E seausens SE Ta AB 7 fe FLET E M Li a mw i c 9 Ok now that you re done with the USB chip and you re pretty sure its soldered correctly solder in all the rest of the components on the IO board When soldering in the MIDI DINSYNC connectors make sure to pre stress them as they are a
8. h assembly by attaching the mainboard to the frontplace and the case with the hex button head screws To keep from overtighting and cracking the panel place the four 4 40 washers in the flanges and tack down with a little glue Just to Keep them from shifting around while attaching the frontpanel to the PCB 5 The back panel is attached by threading the 1 4 jacks through the panel 6 Put the pot knobs on Attach the rubber feet and screw the case together using the longer 4 40 screws 7 Turn on the synth and set it to keyboard or random mode to test the sound generation Make sure you dont start it up into bootloader mode or the firmware wont boot Now would be a good time to read the user manual Parts ABS Case PT 10 m Set of main and I O panels m 15 32 x 1 4 standoff 3 3 8 x 1 4 standoff 4 4 40 lock washer 7 4 40 washer 4 40 x 1 4 hex button 4 40 x 1 4 phillips button i i 8 4 40 x 1 4 phillips cheesehead 1 swear its called that Rubber feet l Switch cap white 8 Switch cap black 15 Potentiometer knob 8 Switch knob 2 s wire jumper ribbon cable 4
9. ips The kit comes with BA6110 which means that Q1 4 are also required If you decide to go with a BA662 do not solder in Q1 4 Also each chip has a different pinout so use IC15B for BA6110 and IC15A for BA662 Dont put in your BA6110 upside down the notch in the chip goes at the end of the socket that has a tapered end in the silkscreened picture pointing north as seen above Testing 1 Connect power from the IO board and provide 2 0VDC to R90 as before 2 In a guiet room connect up a pair of low fi 32ohm or greater impedance headphones as before ground the sleeve and use the tip for probing Touch the tip to rightmost pin the one that is not connected to the ground plane of where the volume potetiometer VR will go 3 Connect up an alligator clip as it was for testing the gate clipped to R146 and touch the other end to R10 to generate a gate pulse You should hear a struck note Hooray you re basically done with the analog section of the synthesizer Parts _ a___ s NA148 3 D35 R130 resistor R132 R125 2 2K 5 p resistor R133 R162 A7K 590 R119 resistor R127 C42 M QQ R W O N O4 032 IC15B BA6110 9 SIP IC15A xOxbOx fabrication manual A last edited May 10 2005 Headphone Mixer 22 Introduction This is the final step of the analogue section the headphone amp volume control and mixer You are here
10. little flimsy press them back so that the face 1s flush with the PCB while soldering them in Be sure to use lots of solder on all the connector components to make a good mechanical bond 10 Power the IO board but don t connect it to the main board 11 Plug in the USB into a computer 12 The computer should detect a Serial lt gt USB chip and request a driver 13 Download the driver from FTDI Make sure to grab the VCP driver Install it Verify that a new COM port is created under Windows look under hardware control panel Parts 1 4 stereo jack 3 MIXIN 1 8 jack 2 CV GATE USB type B jack 1 USB c AANA148 1 D48 resistor FOOD 392 R186 R164 100 ohm 590 Uu resistor 1 5K 590 resistor 2 2K 5 resistor j R21 R24 4 1K 5 resistor 10K 5 resistor 2 RIO R11 HMM 100K 5 resistor 4 R25 R28 luF 104 ceramic 2 C202 C204 MEM 10uF electrolytic 2 C203 C205 capacitor 2SC536F TO 92 NPN transistor Sali FT232 USB chip 1 IC25 history xOxbOx fabrication manual sequencer last edited May 10 2005 Introduction The sequencer is pretty much all of the digital control and I O There are a lot of parts but note many kinds of parts 70 10K resistors 40 LEDs 32 buttons etc You are here A ITUEFERI myn I L 154 E i 4 T e E an i a a 5 i YY YH mu LLL 1 EEN i LETT
11. s the high resonance notes are aciding Tuning There 1s an official tuning for the VCF According to the Roland TB 303 manual when playing C7 65 4Hz with the cutoff freguency knob set to 5090 saw waveform and resonance knob at 100 the resonance frequency should be 500Hz give or take 100Hz depending on how it sounds to you You can perform this tuning by either applying 3 0VDC to the VCO or finishing the entire assembly and using something like Keyboard mode to trigger the note The resonance can be adjusted by tweaking TM3 Parts NA 4 8 D24 100 ohm 5 resistor R95 R67 R65 R69 2 2K 5 resistor 7 R70 R71 R98 R47 R61 R64 R65 R94 R96 R97 R109 R112 R115 R116 10K 5 resistor 11 22K 5 resistor R110 RIII R46 47K 5 resistor R66 R72 R73 100K 5 resistor R99 R113 R114 220K 5 resistor 2 R62 R63 f u 504 trim n LN potentiometer 50K D log potentiometer 50K B linear dual VR4 potentiometer 2 VR3 VR5 018uF 2A183K polyester capacitor e Esc E 033uF 2A333K polyester capacitor 9 C19 C24 C26 25 627 cis C30 ca luF 2A104K capacitor 2 10uF electrolytic capacitor J TuF electrolytic capacitor C13 C14 C15 CHESZ luF electrolytic capacitor 7 2SA733P TO 92 PNP transistor Q11 Q13 Ol4 2SC536F TO 92 0 Q15 Q16 Q
12. se the 2SC536 2SA733 and 2SK30 transistors or the 28C1583 and 2SC2291 matched pairs they look similar The PCB drawings of the 2SK30 show a filled in transistor the drawing of the 28A733 1s hollow with a line through it and the 2SC536 drawing is hollow e The resistors thermistors and non electrolytic capacitors have no polarity This is not true for the diodes transistors electrolytic capacitors and op amp Putting them in backwards can destroy them e Both sides of the jumper J4 have a 1 printed next to the first pin make sure that you have correctly corresponding pins connected e Dont forget that VR2 and SWI are soldered on the top opposite side of all the components Recommended order 1 Solder in all parts except for S1 and VR2 2 Solder in S1 and VR2 on opposite side 3 Do basic calibration testing Testing amp Calibration The VCO can be simply tested without the use of an oscilloscope although it helps a lot The power supply 5 333V must be calibrated before this step I iii fap za Pr ee T gy T Rr a n bn myr e RM jr Linh Ta i Ar A y ay 3 gt j reads 3 nin er Me ab Gr a Apply power make sure J4 is connected with wires With the tuning knob VR2 centered apply 2 0VDC using your powersupply to R89 also pin 5 of IC11 Also center TM4 and TMS to start Usea multimeter with frequency detection or an oscilloscope or a pair of cheap headphones to probe pins 1 or 3 of
13. the waveform switch Switch between 2 0VDC and 3 0VDC to R89 while turning TMS width until the frequency at 3 0VDC is twice that of 2 0VDC If you have an oscilloscope verify also the offset voltages are correct Vmin 6V for saw 5V for square Vmax 11 5V for saw 9V for square if you have only a meter the DC voltage should be 9V for saw 7V for square the AC voltage should be 5V for saw 4V for sguare 54 A 1 Hz PACKARD OSCILLOSCOPE 4 CHANNEL Tuning the sawtooth wave to C1 Note that the tip of the saw isnt sharp also the min and max voltages DE HEWLETT 54602A 150 MHz PACKARO OSCILLOSCOPE 4 CHANNEL E j j E Mel cu e ie Tuning the square wave to C2 Note that the square wave droops slightly and isnt 50 duty cycle Now apply 2 0VDC to R89 and probe the waveform switch again adjusting TM4 tune until you see hear C7 65 4Hz The precise calibration step can be delayed until the rest of the synthesizer 1s completed when you can just press a button to generate 2 0V and 3 0V to the VCO If you don t have a bench power supply you should center TM4 and TMS which will get you close enough and listen to the square waveform using a pair of cheap headphones probe the middle pin of the waveform switch while its set to SQR Now touch the metal leads of the 200K resistors to vary the frequency and turn VR2 and note that the freq
14. uency changes Toggle switch m SWI 1N4148 3 D30 1MEG 590 resistor 502 trim nr TMS potentiometer SOK 503 trim 1 TM4 potentiometer potentiometer 74AC174 aa AI i JE VE d z z G gt 2 34 Gre m o c o 2 35 o 11 Q C32 IC12 ES u C9 00 O 2 T pair with 1 026 Ii common LI emitter xOxbOx fabrication manual _ last edited May 16 2005 VCF Introduction The VCF creates the high freguency sub oscillations as controlled by the cutoff and resonance knobs LIE SII OE LN Ne Notes Again solder in the large potentiometers last Testing At this point one can test whether resonance cutoff affect the note 1 Power up as described in the power supply section connect 3VDC using a power supply or some other method as discussed in the prep section to R90 See below the red hook clip 2 If you have one use a scope to probe the potentiometer twist the cutoff VR3 and resonance VR4 pots all the way down and examine the almost sinusoidal notes 4 Or lacking a scope use a high impedance 32ohm headphone to probe the same pin Connect the sleeve to ground and use the tip to touch the point you want to hear Make sure that its a pair of really cheap headphones high guality ones are as low as 2ohms and will pull the signal low Sinusoudal notes will sound soft wherea
15. xOxbOx fabrication manual nuns last edited May 15 2005 power supply Introduction The power supply is the first thing to build Getting this part right is key A bad power supply will keep the rest of the synth from working so be sure to test it after its built The power supply takes the 9VAC from the power plug and doubles it to 18 VAC which then gets regulated down to 12VDC and also rectifies and converts the 9VAC into 5VDC 6VDC and 2 299 VDC You are here After Umm that grey jumper wire shouldn t be there You should use 3 pieces of every day wire for now the jumper is too delicate to install now Testing amp Calibration Since its easy to destroy electronics if the power supply 15 not built properly it may help to do this section in steps with constant testing Remember to solder with the power disconnected and test with the power connected eh If you plug in the supply at any point charge will build across the large caps which is retained for a while This can cause sparking during soldering later so its a good 1dea to discharge the caps using a screwdriver touch both terminals at once w something metallic 1 Solder the power jack 2200uF caps C3 and C5 and the 4 1N4001 power diodes D40 D43 Test that the votage across the jack terminals 1s 12V AC or so Be sure to solder in the jack flush and square with the PCB and use a lot of solder completely fill the hole with solder as this will reduce the stress on
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