ADSR Upgrade Builder`s Guide
Contents
1. amp does this because it adheres to the golden rules Actually it can only try to adhere to these golden rules Now the golden rule in question is that an op amp with negative feedback must move its output so that its two input pins are both the same voltage The negative feedback is provided by the resistor R1 So as the input signal tries to inject current into the op amps inverting pin via R2 the output will move against this by taking that current away through R1 So a positive input voltage at R2 will lead to the output going negative The ratio of the resistors will determine the gain of the inverting circuit Making both the resistors the same value will mean that the gain of the op amp is 1 That is 5V at the input gives us 5V at pin 1 We now have two copies of the input signal One from U1b is an exact copy and the other from Ula is an inverted version These two voltages are placed across the two ends of the control pot As the pot wiper moves from one side to the other it will tap off a proportion of each signal Consider what will happen with a 5V input signal across input resistor R4 This will give 5V at the output of U1b and 5V at the output of Ula The wiper of the pot can thus move from 5V to 5V In the middle position both voltages take equal precedence and the voltage at the wiper is zero R17 loads the wiper voltage causing the linear pot to behave in a non linear fashion The pot becomes increasingly less sensiti2. 7 R32 R33 R34 R39 R40 R41 470K R4 R8 R12 R15 Capacitors 33pF 2 5mm ceramic C9 C10 C11 C12 100nF 63V axial ceramic C1 C2 C3 C4 C5 C6 C7 C8 2u2 63V electrolytic C13 C14 Discrete Semiconductors BAT 42 Schottky diode D1 D2 D3 D4 Integrated Circuits TL074 quad bi fet op amp U1 U2 U3 U4 Pots All pots 16mm Alpha or equivalent 47K or 50K linear Alpha pot brackets Miscellaneous Leaded axial ferrite beads MTA156 4 way header MTA100 6 way header 3 way 0 1 pin header 0 1 jumper Molex MTA 0 1 header 8 way Molex MTA 0 1 housing 8 way Molex MTA 0 1 header 4 way Molex MTA 0 1 housing 4 way Switchcraft 112APC 1 4 sockets Four knobs ATTACK DECAY SUSTAIN RELEASE 3 off L1 L2 PSU1 PSU2 Oakley MOTM power supply PWR1 PWR2 Synthesizers com power supply NORM for setting normalisation mode NORM for setting normalisation mode INPUTS for connecting to sockets INPUTS for connecting to sockets A D S R to connect to VC ADSR board 4 off to make VC ADSR interconnects Four off mounted either on the Sock4 board or on panel Around 2m of insulated multistrand hook up wire Suitable power lead Additional components required if using optional Sock4 board Molex MTA 0 1 header 8 way Molex MTA 0 1 housing 8 way 112APC Switchcraft 1 4 socket T O I O SK1 SK2 SK3 SK4 Two wire links are to be fitted to L1 and L2 on the
3. Oakley Sound Systems SU Oakley Modular Series VC ADSR Looping Envelope Generator Building the ADSR Upgrade PCB issue 1 Builder s Guide V1 0 01 Tony Allgood B Eng Oakley Sound Systems CARLISLE United Kingdom ATTACK CY ATTACK ATTACK CY DECAY cv po DECAY CV i i e oe SUSTAIN cy SS tll RELEASE RELEASE cy ADSR YCA OUT RI DARLEY DAWLEY MODULAR SYSTEMS YE ADSR VOLTAGE CONTROLLED ADER VCA The left hand figure depicts the single width ADSR Upgrade module This is designed to sit to the right of our single width ADSR VCA module The right hand figure shows the double VC ADSR module This is essentially a ADSR VCA and an Upgrade module behind a common 2U wide panel Both modules contain the Oakley Upgrade PCB but the VC ADSR module also contains the main VC ADSR PCB Introduction This is the Project Builder s Guide for the issue 1 of the ADSR Upgrade and VC ADSR 5U modules from Oakley Sound This document contains a basic introduction to the Upgrade board circuit description a full parts list for the components needed to populate the boards and a list of the various interconnections To build the full 2U VC ADSR module you will need this document and the ADSR VCA Builder s Guide The ADSR VCA Builder s Guide can be found on the ADSR project webpage http www oakleysound com adsr htm To download the latest User Manual which contains an overview of the operation and all t
4. Sock4 PCB If using Molex KK you ll also need at least 16 crimp terminals Suitable lengths of wire to make up the single 100mm interconnect and two cable ties Other Notes The normalisation header is a 3 pin 0 1 header and associating jumper In this jumper position normalisation is activated The normalisation jumper is either fitted on the first two pins or the last It simply sets whether the Attack CV socket is normalised to the Decay CV input if no jack plug is inserted into the Attack CV socket Pin 1 is the square pad on the NORM header When pin 1 and pin 2 are connected the Attack CV input socket is not normalised If you do not need this feature to be selectable simply use a wire link to permanently set your choice Note that the suggested front panel layout uses a small arrow between the attack and decay sockets to indicate the normalisation Thus this front panel layout expect pins 2 and 3 to be linked or jumpered 10 Connections Power connections MOTM and Oakley The PSU1 and PSU2 power sockets are 0 156 Molex MTA 4 way header Friction lock types are recommended This system is compatible with MOTM systems Power Pin number 15V 1 Module GND 2 Earth PAN 3 15V 4 Pin 1 on the INPUTS header has been provided to allow the ground tags of the jack sockets to be connected to the powers supply ground without using the module s OV supply Earth loops cannot occur through patch leads this way althoug
5. d one for the earthing of the jack sockets on the front panel The power supplies to each of the quad op amp ICs are shown separately from the main schematics to avoid cluttering the diagram The four inputs feature identical reversible attenuator circuits Let us consider the first reversible attenuator This takes its input from the line labelled ATTACK CV and has its output at ATTACK OUT The circuit is made up from four individual op amps ATTACK CV comes from pin 8 of the INPUTS header at the bottom of the board and is connected to the signal lug of the ATTACK CV socket R3 and R4 attenuate the signal slightly to prevent any possible damage to the electronic circuits and also provide some protection against static discharges U1b pins 5 6 amp 7 acts simply as a voltage buffer This is a circuit that merely sniffs the voltage across R4 and creates a copy of that signal at its output on pin 1 We are then free to take a bucket full of current from this output without affecting the input at all A bucket full of current must be defined here as anything less 15mA or so Hardly a bucket then is it Tony Ula pins 1 2 amp 3 is a different circuit to the one around U2b This is an amplifier with a gain of 1 This means that its output is the opposite polarity to the input voltage The input voltage is sensed by R2 and the current flowing through R2 is matched by an equal current flowing in the series combination of R1 The op
6. er lead You can make this jumper lead so that each end is terminated in a MTA housing or you can solder the power lead directly into the ADSR board and then use a MTA header housing on the other end that plugs into the Upgrade board Building the Upgrade or VC ADSR module using the Sock4 board This is the simplest way of connecting all the sockets to the main board The Sock4 board should be populated in the way described in our construction guide found on the project webpage There is only one eight way header and it is to be fitted to the bottom side of the board Don t forget to solder in the wire links L1 and L2 You need to make up only one eight way interconnect It should be made so that it is 100mm long A P 2 A The Sock4 makes a very neat job of wiring up the four sockets 12 Hand wiring the sockets If you have bought Switchcraft 112A sockets you will see that they have three connections One is the earth or ground tag One is the signal tag which will be connected to the tip of the jack plug when it is inserted The third tag is the normalised tag or NC normally closed tag The NC tag is internally connected to the signal tag when a jack is not connected This connection is automatically broken when you insert a jack Once fitted to the front panel the ground tags of each socket can be all connected together with solid wire I use 0 91mm diameter tinned copper wire for this job It is nice and stiff so retains
7. ettings Only then are the summed CVs are then passed back to the VC ADSR core This might seem a little odd but it means that the VC ADSR board does not need to have summing circuitry included and thus the PCB can be physically smaller The summing circuitry is only needed with the full VC ADSR module so it was not necessary to put it on the main VC ADSR board which is quite often used without external CV inputs As the output of the mixer is inverting we need to invert it once again to get it the right way up Ulc pins 8 9 amp 10 is configured as yet another inverting amplifier At the output of the final inverting stage is a small voltage limiting network based around a resistor R23 and a Schottky diode D1 These are used to limit the maximum output swing to positive values only A Schottky diode is used because its resistance drops dramatically when it has around 0 2V across it A normal junction diode needs at least 0 6V before this happens When D1 s resistance drops it shunts any excess negative voltage to ground thus preventing the output voltage to drop below 0 2V or so This negative clamping is done to protect the 4052 analogue switch on the VC ADSR board Applying too much negative current to the inputs of this chip will cause it misbehave or possibly die The voltage across the diode is fed to the header A D Here it will travel to the VC ADSR board to control the rise time of the VC ADSR s integrator The other three cha
8. h screening is maintained Of course this can only work if all your modules follow this principle Power connections Synthesizers com The PWR1 and PWR2 power sockets are to be fitted if you are using the module with a Synthesizers com system In this case you should not fit the PSU header The PWR header is a six way 0 1 MTA but with the pin that is in location 2 removed In this way location 3 is actually pin 2 on my schematic location 4 is actually pin 5 and so on Power Location number Schematic Pin number 15V Missing Pin 5V Module GND 15V Not connected 1 NnBWN nA BWW 5V is not used on this module so location 3 pin 2 is not actually connected to anything on the PCB If fitting the PWR header you will also need to link out pins 2 and 3 of PSU1 This connects the panel ground with the module ground Simply solder a solid wire hoop made from a resistor lead clipping to join the middle two pads of PSU together 11 Power connections MOTM Oakley and Synthesizers com The Upgrade module has been fitted with two sets of power headers This is so the Upgrade board can power the connected VC ADSR board Thus only one power lead is required to feed both boards PSU1 and PWR1 are laid out to be directly in line with the power headers on the VC ADSR board If you are building the full 2u version of the VC ADSR module then you can use these headers to simply connect the two boards together with a short 4 way jump
9. he calibration procedures please visit the main project webpage at http www oakleysound com vc adsr htm For general information regarding where to get parts and suggested part numbers please see our useful Parts Guide at the project webpage or http www oakleysound com parts pdf For general information on how to build our modules including circuit board population mounting front panel components and making up board interconnects please see our generic Construction Guide at the project webpage or http www oakleysound com construct pdf Nomenclature VC ADSR PCB The PCB used in the Oakley ADSR VCA module since January 2004 ADSR Upgrade PCB The PCB described in this document that allows the VC ADSR PCB to behave in a fully voltage controlled manner ADSR VCA PCB Our original envelope generator that used passive components as timing controls The PCB was superseded by the issue 1 VC ADSR PCB in January 2004 ADSR VCA module The module that since January 2004 comprises of the VC ADSR PCB and since August 2010 acts as a looping ADSR with a built in VCA on the output VC ADSR module The 2U fully voltage controllable looping ADSR module with integral VCA ADSR Upgrade module A 1U module that connects to an already constructed ADSR VCA module to allow for full voltage control of the attack decay sustain and release parameters The Oakley ADSR Upgrade Module The issue 1 Upgrade PCB and handy Sock4 PCB behind a natura
10. its shape A single piece of insulated wire can then be used to connect those connected earth tags to pin 1 of I O Pin 1 is the square solder pad All the other connections are connected to the signal lugs of the sockets The table below shows the connections you need to make Pin Pad name Socket Connection Lug Type Pin PANEL GND Connect to all sockets Earth lugs Pin2 RELEASE CV Connect to RELEASE CV Signal lug Pin3 GROUND Connect to DECAY CV NC lug Pin4 DECAY CV Connect to DECAY CV Signal lug Pin5 GROUND Connect to SUSTAIN amp RELEASE CV NC lugs Pin6 SUSTAIN CV Connect to SUSTAIN CV Signal lug Pin7 ATTACK NC Connect to ATTACK CV NC lug Pin ATTACK CV Connect to ATTACK CV Signal lug Board to Board Interconnects Make up two sets of four way interconnects Each one will be terminated in either a Molex or MTA 0 1 housing Make sure if you have used Molex headers on your PCBs that you use Molex housings Likewise make sure that MTA headers will be mating with MTA housings Select the length of each wire in the interconnect so that they will reach from the Upgrade PCB to the VC ADSR PCB If you are making the 1U ADSR Upgrade module and have your ADSR VCA module on a separate front panel I would suggest making the leads long enough so you can extract either module from your modular case without the leads getting stretched 13 Final Comments If you have any problems an excellent source of support is the Oakley Sound Forum at Muffwigg
11. l finish MOTM format Schaeffer panel The Upgrade board is designed to be used with the Oakley VC ADSR boards It enables the four parameters attack decay sustain and release to be under full voltage control The Upgrade board connects with the VC ADSR board via two four way hidden interconnects The Upgrade board takes 1U of panel width and requires four socket inputs It can be fitted into either its own 1U panel or be part of a 2U panel shared with the VC ADSR board For the sake of clarity in this document we will refer to the 1U panel normally as the Upgrade module and the 2U panel as the VC ADSR module Please note in order to upgrade a ADSR VCA module you need to have a VC ADSR main board Very early versions of the Oakley ADSR VCA module prior to 2004 used passive methods of controlling the attack decay and release times and are not suitable for upgrading Your VC ADSR board should be clearly marked as VC ADSR if you want to have the ability to upgrade Those marked as ADSR VCA and normally fitted with the green Omeg Eco 16mm pots will not work The design requires plus and minus 15V supplies The power supply should be adequately regulated The current consumption is around 25mA Power is routed onto the PCB by a four way 0 156 MTA156 type connector or the special five way Synthesizers com MTA100 header The four pins of the four way connector are 15V ground earth panel ground 15V The earth panel connection a
12. ler com Paul Darlow and I are on this group as well as many other users and builders of Oakley modules If you can t get your project to work then Oakley Sound Systems are able to offer a get you working service If you wish to take up this service please e mail me Tony Allgood at my contact e mail address found on the website I can service either fully populated PCBs or whole modules You will be charged for all postage costs any parts used and my time at 25GBP per hour Most faults can be found and fixed within one hour and I normally return modules within a week The minimum charge is 25GBP plus return postage costs If you have a comment about this builder s guide or have a found a mistake in it then please do let me know But please do not contact me or Paul Darlow directly with questions about sourcing components or general fault finding Honestly we would love to help but we do not have the time to help everyone individually by e mail Last but not least can I say a big thank you to all of you who helped and inspired me Thanks especially to all those nice people on the Synth diy and Analogue Heaven mailing lists and those at Muffwiggler com Tony Allgood at Oakley Sound Cumbria UK November 2010 No part of this document may be copied by whatever means without my permission 14
13. llows you to connect the metal front panel to the power supply s ground without it sharing the modules ground line More about this later Provision is also made for a second power connector to allow any connected VC ADSR board to take its power from the Upgrade board Thus allowing both boards to be powered from just one main power cable The PCB has four mounting holes for M3 bolts one near each corner These are not required if you are using the three 16mm pot brackets The board size is 143 mm high x 74 mm deep Circuit Description The board simply consists of four identical attenuator and mixer circuits along with various headers to allow the signals on and off the board and to provide connection to the power supply Power is applied to the board through the PSU2 a 4 way MTA156 Molex 0 156 connector or PWR2 a special five way MTA header F1 and F2 small axial ferrite beads provide some high frequency resistance and along with C13 and C14 prevent the board from being effected by any noises on the power rails They also help keep any unwanted noises going the other way too Additional decoupling is also provided elsewhere on the board by eight other capacitors shown above right of the power inlet circuitry These capacitors keep the power supply clean of noise and provide a reservoir for the little bursts of current that the circuit takes in normal operation Two grounds are provided one for the circuit itself an
14. nnels are identical in operation to the attack channel The suggested layout normalises the decay CV input to the attack CV when no jack is inserted into the ATTACK CV socket This requires 3 way header NORM to be fitted and a jumper put across pins 2 and 3 If normalisation is not required the jumper should be fitted to fit across pins 1 and 2 Parts List For general information regarding where to get parts and suggested part numbers please see our useful Parts Guide at the project webpage or http www oakleysound com parts pdf The components are grouped into values the order of the component names is of no particular consequence A quick note on European part descriptions R is shorthand for ohm K is shorthand for kilo ohm R is shorthand for ohm So 22R is 22 ohm 1K5 is 1 500 ohms or 1 5 kilohms For capacitors luF one microfarad 1000nF one thousand nanofarad To prevent loss of the small as the decimal point a convention of inserting the unit in its place is used eg 4R7 is a 4 7 ohm 4K7 is a 4700 ohm resistor 6n8 is a 6 8 nF capacitor This board may also be used with our older simpler front panel design However there are small differences to the board components used for each option Resistors All 5 carbon 1 4W or better 4K7 R23 R30 R37 R44 8K2 R17 R24 R31 R38 10K R3 R7 R11 R16 33K R1 R2 R9 R10 R5 R6 R13 R14 R21 R22 R28 R29 R35 R36 R42 R43 100K R18 R19 R20 R25 R26 R2
15. ve near the middle of its rotation thus making it easier to control small levels of modulation The two four way headers A D S R and the additional power header PSU1 on the Upgrade board that connect to the adjacent VC ADSR board The voltage at the wiper and therefore across R17 is connected to another inverting amplifier based around Uld pins 12 13 amp 14 The op amp s gain is also minus one So a voltage of 5V at the wiper of the pot will give 5V at the op amp s output The amplifier has another resistor connected to its input pin R20 This resistor is very important to us building the VC ADSR and Upgrade modules The current flowing in R20 will sum with that flowing in the other input resistor In other words this circuit will mix the wiper voltage with the voltage present at the point labelled ATTACK IN This point goes back to one of the pins on a four way header called A D The decay channel also uses the A D header whilst the sustain and release channels use another header called S R The headers are shown at the bottom right of the circuit diagram You can see each one has two inputs and two outputs This is because the A D and S R headers serve two purposes One they allow the Upgrade board s output voltages to get to the VC ADSR board And two they allow for the ADSR s pot settings to be sent to the Upgrade board The Upgrade board not only processes the input CVs but also adds them to the VC ADSR board s own s
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