MOTM-800 User Manual
Contents
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3. is using the No Clean solder You do not have to wash the board anymore PART 6 FINISHING THE PCB You will now solder in the remains parts on the pcb in preparation for wiring to the front panel USE THE NO CLEAN SOLDER BE CAREFUL SYNTHESIS TECHNOLOGY PAGE 7 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM g Locate the 3 Bourns 1M log pots IMPORTANT in order for the pc board to properly align into the front panel each pot must be absolutely flat on the pc board with the shafts pointing away from the pc board NOTE the 3 holes the leads go in are small on purpose The leads will go into the holes you will have to be gentle and slowly press the part down onto the pc board Solder the pots into VR1 VR2 and VR4 Solder the Bourns 10K linear pot into VR3 g Locate the WIRE bag Note that the pre stripped wires all have a short end and a longer end THE SHORT END GOES IN THE PC BOARD g Locate the 3 pieces of RG 174 black coax cable Again note that one end has longer wires stripped than the other The short ends will go in the pc board in positions J2 43 amp J4 Look at the pc board Notice that in positions J2 J4 there is a large hole pad lower pad and a smaller pad top hole The braided wire 1s soldered into the larger hole The smaller inner conductor goes in the top hole Note there is a row of plain holes along the bottom under J2 4 These holes are for threading the small white tie wraps for holding
4. remember the actual output 1s divided by 2 From the above discussion you should now see how each portion of the A D S amp R are generated All we need now is some control logic to sequence the analog switches in the proper order The MOTM 800 control logic consists of NPN transistors Q1 amp Q2 the 555 timer U2 switch section U1C and the 2 diodes D2 amp D3 Let s assume for the first discussion that our keyboard generates BOTH a GATE and a TRIGGER pulse Once we trace the operation in this mode the other 2 modes will make more sense Assume you have a GATE plugged in which disconnects tricky resistor R15 and a TRIGGER plugged in With no key pressed the GATE is OV Transistor Q1 is OFF which means it s collector pin is 15V This 15V in turn turns ON transistor Q2 which means it s collector pin is at OV we just made a complicated wire The reason it is done this way is that we need a GATE and a GATE signal Transistors Q1 amp Q2 do this cheaply Diode D1 1s to protect Q1 in case the GATE voltage goes below ground like you plugged a LFO into it The NO_GATE signal is used to control switch U1A the RELEASE portion We want a RELEASE when the GATE goes away So just sitting there the cap C9 is held in discharge Now let s turn our attention to the not a timer this time U2 Pin 4 is the RESET pin If it is at ground the 555 turns off The GATE signal collector of Q2 controls this pin If
5. that 1s disconnected when a plug is inserted and the bevel is ALWAYS ground Solder the TRIG J2 coax into the jack The braid goes to the BEVEL the inner wire goes to the LEFT lug Solder the wire in the TRIG MOD hole to the TOP lug switched connection Solder the WHITE wire in GATE J1 to the LEFT lug of the GATE jack Solder the ORANGE wire of J1 to the TOP lug of GATE jack Solder the GRAY wire to the BEVEL lug of the GATE jack Solder the coax in OUT J4 to the LEFT lug of the OUT jack Solder the braid to the beveled side Solder the coax in OUT J3 to the LEFT lug of the OUT jack Solder the braid to the beveled side Rotate all of the front panel pots fully counter clockwise Locate the KNOBS Notice each knob has a thin white line on it Place the knob on the pot shaft align the white line to the 0 tick mark and tighten the hex screw The silver part of the knob has a protective clear plastic overlay that can be removed if desired Gently rub with your fingernail and it will peel off kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk CONGRATULATIONS YOU HAVE FINISHED BUILDING THE MOTM 800 kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk All that s left to do is test it But before we do please read the following Theory of Operation The MOTM 800 can be used in several ways depending on your type of keyboard MIDI to CV converte
6. the panel to the right and the power connector to the left g All of the IC are pointing the same way all notches are to the left C1 amp C2 stripes are both pointing upwards D1 and D2 banded ends are both pointing downwards Transistors Q1 amp Q2 s flat sides are facing to the right The braided wire on the coax goes to the beveled side of the jacks U Q UYU Q The board has all the right parts in all the right places g No solder shorts or missing joints If you still can not get the module to perform correctly please contact us by phone fax at 888 818 MOTM or by email to synth1 airmail net Thank you for purchasing the MOTM 800 kit SYNTHESIS TECHNOLOGY PAGE 16 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM SPECIFICATIONS MOTM 800 ADSR ENVELOPE GENERATOR ATTACK DECAY RELEASE time SUSTAIN voltage GATE input voltage TRIGGER input voltage TRIGGER input pulse width Output Impedance GENERAL Power Supply Size Depth behind panel SYNTHESIS TECHNOLOGY MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM 1ms to 14 seconds typical 0 to 4 95V 0 to 13 4 0V min 13 max 50045 min 1K typical 15VDC 5 ma 15VDC 10 ma 1U x5U 1 74 x 8 72 44 2mm x 221 5mm 2 43 inches 61 6mm PAGE 17
7. why 15V to charge Don t we want eventually a 5V envelope out If we are dividing by 2 why don t we charge to 10V SYNTHESIS TECHNOLOGY PAGE 12 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM The reason is that a charging capacitor in theory will NEVER get to a final charge In practice internal leakage and resistance in the cap also causes the voltage to droop a little Therefore we cheat We purposely set the charging voltage higher than what we really want In this case we charge the cap towards 15V but stop charging when we get to 10V The RELEASE portion is just the opposite of ATTACK instead of charging we discharge the cap to ground This is done by switch U1A which is tied to RELEASE pot VR4 When pin 13 is 15V the switch closes and the cap C9 discharges through VR4 to ground This forms the RELEASE portion of the envelope Of course we need to turn OFF switch U1D in order to do this The DECAY SUSTAIN portion is a little trickier This is done using switch U1B VR2 DECAY VR3 SUSTAIN and importantly R9 Assume C9 is charged to 10 and switch UID opens If we then close U1B what does the voltage on C9 do Well it goes to the voltage set by divider R9 amp VR3 at the rate set by VR2 Note that if R9 is not set to the right value instead of discharging to a lower voltage the cap will actually charge to some higher voltage So we choose R9 to set our max sustain voltage at 10K 15 1K 15V or 9 9V
8. RE bag locate 4 6 32 3 8 screws 6 6 KEPS nuts and 4 Spacers Locate the mounting bracket The pc board attaches to the bracket with the 4 screws threading from the top of the board through the spacers through the bracket and then out the bottom of the bracket The Z6 KEPS nut attaches on the bottom of the bracket Note the bracket has 2 long mounting flanges with a hole in each These attach to the 2 threaded studs sticking out of the rear of the panel The 4 pots each stick in it s panel hole when the bracket 1s screwed down on the 2 threaded posts Attach the pc board to the bracket The 2 mounting flanges are located in between VR1 amp VR2 and next to VR4 The flanges will point upwards when the pc board is sitting on the bracket Note that the bracket holes for the pc board are actually oblong This is to allow adjustment for the pc board to firmly press up against the back of the panel As a start set the 4 screws ALL THE WAY TO THE LEFT of the oblong holes Loosely tighten the 4 KEPS nuts on the bottom THIS IS A VERY IMPORTANT STEP SO PAY ATTENTION AND READ ALL OF IT BEFORE PROCEEDING Note that each of the 4 pots on the pc board have 2 hex nuts and a flat washer Remove the first hex nut and the washer Set aside What you will do now is adjust the remaining hex nuts so that when the bracket 1s all the way down on the panel s threaded studs all the pot hex nuts touch the rear of the panel Screw by hand each he
9. SH 101 etc do in fact drop the GATE signal SYNTHESIS TECHNOLOGY PAGE 14 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM TRIGGER ONLY This is used mainly with drum pad devices When the pad is struck the circuitry outputs a short pulse If you only drive into the TRIGGER jack then a false GATE is provided by resistor R15 Therefore the MOTM 800 acts like a standard ADSR EG receiving new triggers when the GATE 1s still high As discussed previously this causes a new ATTACK phase followed by a DECAY SUSTAIN phase There is no RELEASE because the GATE is always there via R15 What useful waveform s can we generate The most common use is called an AR envelope although the MOTM 800 uses an A D cycle If you turn SUSTAIN to 0 remember RELEASE is ignored then the ATTACK and DECAY pots will set the envelope This is how you stretch the narrow TRIGGER pulses into longer envelopes However the SUSTAIN pot is still functional If the pot is NOT zero then the output of the MOTM 800 will be the SUSTAIN voltage with no TRIGGER In other words a D C bias voltage will be on the envelope instead of ground This is also quite useful One novel use of a spare MOTM 800 is to not connect anything to GATE or TRIGGER and use the OUT and OUT jacks as positive and negative bias voltages to other modules CONNECTING LFOS TO THE MOTM 800 If you want to have a stream of envelopes generated by a LFO connect the LFO SQUARE o
10. ches 10 resets the internal flip flop and drives pin 3 off C9 then discharges through VR2 towards the sustain voltage set by VR3 Now the circuit waits for the GATE input to go to ground This turns on U1A discharging C9 through VR4 thus completing the ADSR cycle The MOTM 800 features a re triggerable ATTACK If the GATE is high and you get a new TRIGGER this will set the 555 s flip flop disconnect the DECAY SUSTAIN logic and close UID again for a new ATTACK cycle MODES OF OPERATION In this section we will discuss how the MOTM 800 1s used in various applications Of course these are only a few things to try Experiment GATE amp TRIGGER INPUTS USED Generates an ADSR cycle as the note 1s pressed IF your system generates a new trigger when a key is pressed while another key 1s still down the new trigger generates an ATTACK DECAY phase MIDI to CV converters such as the Kenton Pro 2000 can be set to generate new triggers on newer notes played GATE ONLY Many keyboards with CV amp GATE outputs do not have triggers Therefore the TRIGGER jack on the MOTM 800 is left unconnected The TRIG MOD wire generates a fake trigger pulse when the GATE input goes high This causes the MOTM 800 to generate a full ADSR cycle without a trigger pulse However unless your keyboard drops the GATE momentarily when a new key is pressed the new ATTACK DECAY portion will not be generated Most Roland synths with CV GATE outputs
11. e found for about 1 SYNTHESIS TECHNOLOGY PAGE 4 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM The other type of solder is called No Clean Flux because as the name implies it does not require washing This solder is used on wiring the pots switches jacks etc This solder is harder to use on the pc board because even when melted it 1s not very fluid about the consistency of toothpaste We will use it VERY SPARINGLY on the pc board OK let s get started on the board PART 1 SOLDERING THE RESISTORS Since there are more resistors than anything else we will start here If you do not know the resistor color code refer to the parts list Resistors are not polarity sensitive but the board will be easier to debug and look nicer if you point the first color band in the same direction for all the parts The color code is also in the README FIRST document that every customer gets with their first order C Find the RESISTOR bag g Find the MOTM 800 blank pc board There is a copy larger than actual size of the silkscreen which shows where the parts go at the end of this document It will be useful if you locate the part on the print first put the part in the board then check off the silkscreen All parts are inserted from the side of the board with the white silkscreen the top side g We will stuff the resistors by value to make things easier The resistors and other long leaded parts are inserted on 0 4 inch spaci
12. e hole 1 of J1 Tie wrap the wires to the pc board Solder the small 22ga wire into the TRIG MOD hole YOU ARE NOW FINISHED WITH THE PC BOARD WORK BREAK TIME PART 7 FRONT PANEL PREPERATION You will now attach components to the front panel It is HIGHLY recommended that you use a set of hollow shaft nut drivers NOT PLIERS to tighten the nuts This prevents scratching NOTE all references to part orientation 1s from the REAR of the panel Locate the 4 Switchcraft jacks Notice that from the rear there is a beveled corner This corner is ALWAYS CONNECTED TO GROUND USUALLY WITH THE BRAIDED CONDUCTOR Each jack has a flat washer a lockwasher and a hex nut Remove the nuts and washers from each jack Place aside Keep the lockwasher on the jacks Insert the 4 jacks lockwashers with the beveled corner in the upper right corner into the 4 holes Place the flat washer on the jack then the hex nut Hold the jack with one hand on the backside keeping it square Tighten the hex nut with a nut driver NOTE when tight not much of the exposed threads of the Jack are exposed Check to see that each jack has the bevel in the upper right corner and all jacks are neatly lined up You are now ready to attach the pc board to the bracket and then wire up to the panel SYNTHESIS TECHNOLOGY PAGE 9 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM PART 8 ATTACH PC BOARD TO BRACKET PANEL In the HARDWA
13. e nose or chain nose pliers Diagonal cutters Allen key set for securing the knobs 1 16 Lead bending tool optional but makes the job go much faster DVM or oscilloscope to check the output lt lt For more information of tools used and suggestions see the MOTM FAQ and Tutorial pages at www synthtech com HOW TO FOLLOW THE DIRECTIONS Please read the entire instruction before proceeding There may be valuable information at the end of the instruction Each instruction has a check box next to it After you complete the instruction check the box This way you can keep track of where you are in the process VERIFY THE PARTS LIST g Verify that all of the parts are in the kit as shown on the parts list A WORD ON SOLDERING There are 2 very different types of solder used in the kit Most of the soldering uses Organic Flux solder This is strictly for use on the pc board and is NOT to be used on the front panel wiring In order for solder to stick to the copper a chemical called flux is embedded in the solder The flux leaves a residue on the pc board that should be cleaned with warm water DO NOT USE SOAP OR OTHER CLEANSERS Most of the parts 1n the kits are waterproof and can be washed in the sink The flux is OSHA approved for flushing down the drain so don t worry about that A soft brush 1s used to gently scrub the board We recommend a fingernail brush which is about 1 x 2 and can b
14. ng The important thing is to be sure that the part is sitting all the way down on the board Push the leads in the holes push the part on the board and then bend the leads on the bottom outwards to a 45 degree angle roughly This is called cinching the leads keeps the part from falling out From the bottom of the board solder with the organic flux applying heat to the pad for about a half second first then applying just enough solder to make a small flat puddle The rule of soldering don t use too much you can always add more Cut the leads flush with the top of the solder Locate the 100K resistors and solder into R5 R6 R10 amp R11 Locate the 10K resistors and solder into R1 R2 amp R15 Locate the 1M resistor and solder into R7 Locate the 2K resistors and solder into R13 amp R14 Locate the 1K resistors and solder into R12 and R16 Locate the 5K1 5 1K resistor and solder into R9 SYNTHESIS TECHNOLOGY PAGE 5 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM g Locate the 47K resistors and solder into R3 R4 amp R8 That should be all of the resistors And guess what you are about 1 3 of the way done PART 2 BOARD WASH 1 g Verify all the resistors are in the correct position g Verify all the resistors are flat on the board Correct if needed Check solder joints g Wash the board in warm water gently scrubbing both sides 0 Shake the board couple of time blot dry with an old to
15. nto U3 Note that Pin 1 is the square pad Pin 1 is the pin near the very small dimple in the top of the part All of the ICs point to the left on the pc board The parts may be marked 072BD or tTL072CP depending on manufacturer Locate the TLC555CP timer Solder into U2 Locate the HCF4066BE switch Solder into U1 g Locate the 2 2N3904 NPN transistors Look closely they are marked on the flat side of the part Note the hole pattern on the pc board has the middle lead slightly forward Insert the 3 leads with the bottom of the part about 1 8 from the pc board DO NOT try to push the transistor all the way down on the board Solder g Locate the 1N4148 signal diodes These are a clear glass axial parts with a black band around one end Solder into D1 D2 D3 amp D4 Notice that the silkscreen symbol has a distinct band on one end Insert the banded end called the cathode into the pc board in the correct pad All 4 diodes point down PART 5 WASH THE BOARD AGAIN g Verify all the parts are in the correct locations Check the diodes and C1 amp C2 orientation Make sure all the ICs are pointing the same way g Inspect the solder joints Any solder shorts Too much solder Missing joints g Wash the board under warm water Scrub gently Dry THIS IS A GOOD STOPPING PLACE TO REST OR PUT THE KIT AWAY UNTIL LATER You are now finished with the Organic flux solder All soldering past this point
16. ollowing 3ea 1M log Bourns 91A1DB28D25 VR1 VR2 VR4 lea 10K linear Bourns 91A1AB28B15 VR3 g Front panel SYNTHESIS TECHNOLOGY PAGE 2 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM MOTM 800 PARTS LIST cont o OOO Mounting bracket small Wire bag containing the following 6 wires 3ea RG 174 coax 4 1 2 inches lea 3 wire set 22ga 2 1 2 inches white orange gray lea 22ga wire 2 lea Power Cable 20 Hardware bag containing 4ea 8 32 x 3 8 black screws for mounting module to rack 4ea 6 32 x 3 8 zinc screws for attaching pc board to bracket 4ea 1 8 inch aluminum spacers 6ea 6 KEPS nuts 2 for attaching bracket to front panel 4 for pc board 4ea small tie wraps Organic Solder No clean Solder PC Board MOTM 800 SYNTHESIS TECHNOLOGY MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM PAGE 3 GENERAL INFORMATION Thank you for purchasing the MOTM 800 ADSR EG If you have any issues concerning the building or use of the kit please contact us at 817 498 3782 or by email synth1 airmail net This kit should take the average builder between 1 and 2 hours However please remember this is NOT a speed contest it is an accuracy contest There is no rule that you have to complete the entire kit in one session as long as you wash the flux off Successful kit building relies on having the proper tools Here is a list of what you will need to build your MOTM 800 Soldering iron 50W max power Needl
17. r or drum triggers SYNTHESIS TECHNOLOGY PAGE 11 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM ELECTRICAL THEORY OF OPERATION Envelope generators work by charging and discharging a capacitor at different rates The ATTACK pot VR1 sets the charge rate of the capacitor C9 There 2 discharge rates DECAY set by VR2 and RELEASE set by VR4 The DECAY discharge is to the voltage level set by SUSTAIN pot VR3 The RELEASE discharge is to ground A true ADSR EG needs two input signals a GATE and a TRIGGER These are generated by MIDI to CV converters that are normally use to control your MOTM we suggest the Kenton Pro2000 A GATE signal is normally at ground 0 volts When a key is pressed on the keyboard the GATE signal goes to a positive voltage usually 5V although some keyboards can output up to 12V As long as the key is held down GATE is on A TRIGGER is a short pulse that happens only at the beginning of a note being pressed Not all keyboards will produce a TRIGGER pulse Roland SH 101 for example In these cases you will not get true ADSR function explained later In order to emulate some older monophonic keyboard actions MIDI to CV converters can be set up to send a new TRIGGER pulse out if a key is down and a lower key is then pressed The GATE never goes low but a new TRIGGER pulse is generated The newer note will then ATTACK the old note is sitting at the SUSTAIN point Lastly some drum trigger
18. s are only that TRIGGERs There is no GATE output You whack the pad and a short pulse comes out The MOTM 800 can handle all three scenarios GATE amp TRIG GATE only or TRIG only Look at the schematic The MOTM 800 is based around 2 chips a 555 timer U2 anda quad CMOS switch U1 The 555 is NOT being used as a timer rather we are using the inside guts as a collection of devices Specifically we are using the internal flip flop and voltage comparator The CMOS switches are normally open and are closed when a voltage of 15 is on the control pin These are not perfect switches they will have a on resistance of about 60 ohms This ON resistance sets the shortest charge discharge times for the cap C9 Look at C9 One end is tied to ground The other end is tied to 3 of the CMOS switches This is the manner the ADSR envelope cycles through each section All we need to do is control when each switch opens and closes The amp U3 is used as a buffer for the voltage on the cap The buffered voltage is either divided by 2 by R13 amp R14 for the OUT signal or inverted by U3B for the OUT signal The reason for this division will be explained shortly Let s start with the ATTACK portion Since ATTACK 1s a charging function we need to connect C9 to a voltage source This is the function of switch U1D When the voltage on pin 6 15 15V the switch closes This charges C9 by a rate set by towards 15 But
19. synthesis technology MOTM 800 ADSR Envelope Generator Assembly Instructions amp Owner s Manual Synthesis Technology 6625 Quail Ridge Dr Fort Worth TX 76180 817 498 3782 www synthtech com Oct 18 1999 MOTM 800 PARTS LIST Please carefully check that all parts are in your kit If you have a suspected shortage please call or email If you get free extra stuff keep it for next time g Capacitor bag containing the following 9 parts 2ea 10mfd 25V or 50V Electrolytic C1 C2 lea 3M3mfd bi polar Electrolytic C9 lea 1000pf marked 1N or 102 yellow box C3 lea 0 01mfd marked 10N or 103 yellow box C4 4ea 0 1mfd marked 104 ceramic axial C5 C6 C7 C8 g Resistor bag containing the following 16 parts 4ea 100K 5 brown black yellow R5 R6 R10 R11 3ea 10K 5 brown black orange R1 R2 R15 3ea 47K 5 yellow violet orange R3 R4 R8 2ea 2K 5 red black red R13 R14 2ea 1K 5 brown black red R12 R16 lea 5K1 5 green brown red R9 lea 1M 5 brown black green g IC bag containing the following 9 parts lea TL072 op amp U3 lea TLC555CP CMOS timer U2 lea HCF4066BE Quad CMOS switch U1 2ea 2N3904 NPN transistor Q1 Q2 4ea 1N4148 signal diode D1 D2 D3 D4 g Misc 1 bag containing the following 3 parts 2ea Axial ferrite beads plain gray things L1 L2 lea MTA 156 power connector JP1 Knobs 4ea ALCO PKES90B1 4 g Jacks 4ea Switchcraft 112A g Pots containing the f
20. the coax against the pc board The holes are designed so that coax exits the pads directly under The coax then lies between the 2 holes The tie wrap enters the left hole from the top comes out the right hole from the bottom and is then secured so that the coax is tightly held against the top of the pc board Note that the tie wraps must thread from the top or there may not be sufficient room between the pc board and the mounting bracket The excess tie wrap is cut off See the illustration pages SYNTHESIS TECHNOLOGY PAGE 8 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM Solder then tie wrap the 3 short coax cables 2 J3 amp J4 Trim the excess tie wrap NOTE because of the way the coax is made chances are more of the braid will go in the hole than the inner conductor This is normal unlike all the other parts and wires The secret is to get the coax firmly soldered and tied down You may find it easier to tie wrap first then solder Find the 3 wire bundle has a tie wrap in the middle Note that the ends of the wire are stripped but there is a small piece of insulation still on the wire Slide this off and apply a small bit of solder to the ends this is called tinning the lead It just keeps the wire from unfraying Remember the shorter exposed end goes into the pc board Solder the WHITE into the TOP hole 3 of J1 Solder the ORANGE wire into the MIDDLE hole 2 of J1 Solder the GRAY wire into the bottom squar
21. utput to the GATE input of the MOTM 800 Of course the combined ATTACK and RELEASE pot settings cycle time of the envelope must be less that the period of the LFO driving signal Diode D1 will clip off the negative portion of the LFO waveform protecting the base emitter junction of Q1 SYNTHESIS TECHNOLOGY PAGE 15 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM USE OF THE MOTM 800 ADSR EG The most common use of an envelope generator is to control the volume profile of each note To do this you need a Voltage Controlled Amplifier VCA like the MOTM 110 The MOTM 800 generates control voltages not audio signals The OUT jack is patched to the CV IN jack of the VCA The output audio from your patch is to the IN of the VCA When you play a note the envelope controls the output volume of the note Also most synthesizer patches simultaneously modulate the cutoff frequency of a Voltage Controlled Filter like the MOTM 400 with a different envelope shape that controls the VCA Therefore a standard synthesizer patch uses 2 MOTM 800s one for the VCA and one for the VCF Since the output of the MOTM 800 is a control voltage you can use it for controlling the MOTM 700 Dual 2 1 VC Router Long ATTACK RELEASE envelopes can switch in out audio sources TROUBLESHOOTING If your MOTM 800 does not work please verify ALL of the following before contacting us The following reference directions assume that you are looking at the pc board with
22. we have no GATE input the 555 is OFF When the GATE goes high the 555 is armed and ready to work SYNTHESIS TECHNOLOGY PAGE 13 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM So THAT is why tricky resistor R15 is used on the switched portion of the jack J1 If your setup has TRIGGER only R15 provides a phantom GATE signal that arms the 555 timer More on this later Now that the 555 is armed we need a TRIGGER pulse Pin 2 of the 555 is an input to a SET RESET flip flop When the 555 sees a trigger pulse the flip flop SETs and pin 3 goes to 15 We interface to the outside world by using a resistive divider R5 amp R6 to set the trip level of the flip flop to about 7 5V Then we AC couple to the 555 with capacitor C3 This forms a glitch circuit that will set the 555 with our 5V input TRIGGER signal The TRIGGER pulse causes pin 3 to go high which turns on U1D charging cap C9 for the ATTACK phase Now we turn our attention to the 555 pin 6 This is the threshold input to reset the internal flip flop The voltage that causes a reset is 2 3 of or 10V How convenient This is how we turn off the ATTACK and turn on the DECAY SUSTAIN circuits U1C is acting as an inverter which 1s connected to diode D2 This diode D3 and R8 form an AND gate When the voltages on the cathodes are both 15V pin 12 of U1B goes to 15V This turns on the DECAY SUSTAIN cycle which happened when the threshold pin of the 555 rea
23. wel the leads will frazzle the good towel Let dry about 15 minutes PART 3 CAPACITORS g Locate the CAPACITOR bag Locate the 1000pf yellow box cap Top is stamped 1N or 102 Solder into C3 Locate the 0 1mfd axial ceramic caps marked 104 Solder into C5 C8 0 0 g Locate the 0 01mfd yellow box cap Top is stamped 10N or 103 Solder into C4 g Locate the 10mfd electrolytics Note that there is a stripe on the NEGATIVE terminal The pc board has a on the POSITIVE terminal Carefully stick the capacitors into C1 and C2 with the stripe away from the pad on the board g Locate the 3M3 bi polar electrolytic It is dark blue with the letters BP stamped on it This type of electrolytic is NOT polarity sensitive Solder into C9 PART 4 MISC and IC STUFF Almost done with the parts on the pc board This will finish up the soldering with the organic flux g Locate the MISC 1 bag and the IC bag g Locate the ferrite beads They are axial parts gray colored with no markings These are non polar and are soldered into L1 and L2 SYNTHESIS TECHNOLOGY PAGE 6 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM g Locate the MTA 156 power connector Solder into JP1 Note that the connector has a locking tab on one side This side is the inside facing relative to the pc board Note the silkscreen symbol for JP1 has a line on one side indicating this 1s the side where the locking tab goes Locate the TL072 amp Solder i
24. x nut on the pots so that it is all the way on touching the face of the pot Now pick up the pc board bracket assembly and carefully slide it over the 2 threaded studs making sure the pots are aligned in the holes Use 2 6 KEPS nuts and tighten the bracket to the panel Loosen the 4 KEPS nuts on the bottom of the bracket Slide the pcb ALL THE WAY TO THE RIGHT AS FAR AS IT WILL GO so that the 4 pot nuts are all pressing against the panel By hand put hex nuts on the outside threads of VR1 and VR4 to keep the pc board in place Now tighten the 4 KEPS nuts on the bracket The pcb and bracket should be secure with no gaps visible between the panel and the pot nuts You may need to loosen the nuts on the pots so that they are touching the back of the panel Again make sure each pot s nut is touching the back of the panel no gaps There will be a gap from the edge of the pc board to the panel Remove the hex nuts on VR1 amp For all 4 pots first put on the flat washer Then the hex nut Tighten with a nut driver SYNTHESIS TECHNOLOGY PAGE 10 MOTM 800 ASSEMBLY 10 18 99 WWW SYNTHTECH COM PART 9 FINISH WIRING TO THE PANEL Now you will solder the coax wires to the jacks You will solder the top row of jacks first then the bottom row Note that from the rear the jack lugs are referred to as LEFT TOP and BEVEL The left lug is the signal from the outside plug the top lug is the switched signal
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