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the characteristic ‘dow’ sound. Oddly, the envelope amount also gets higher for repeated
triggering of the gate.

GATE LED:

 Lights green when an active gate is present.

VCF DECAY:

 Controls the time it takes for the envelope to decay down to zero. From ‘dit’

sounds to ‘dowww’ sounds.

ACCENT DECAY:

 This will allow the filter decay time to be a certain proportion of the time

set by the VCF DECAY pot when accent has been triggered. In other words you can set the
accent decay time from very short to the same as the VCF DECAY time.

FILTER MODULATION:

 Adjusts how much of the selected VCO output modulates the

VCF’s cut-off frequency. This brightens up dull timbres and somehow gives them a burbling
sound. Use with high values of resonance for really odd noises. Remember that the source of
the modulation comes from the VCO WAVE switch. So changing the waveform makes a huge
difference to the sound.

VELOCITY CONTROL:

 This switch turns the velocity processor on or off. With it off,

velocity has no control over the slides and accent modes of the 3031. When on, the velocity
processor measures the value of the velocity CV and controls the synth accordingly.

Example velocity CV processor sensitivity:

Velocity CV

Approx MIDI value

Slide

Accent

0-2V

0 -31

no

no

2-4V

32-63

no

accent

4-6V

64-95

slide

no

6-10V

96-127

slide

accent

Adjust the SENS trimmer for actual processor sensitivity.

Although it is called velocity control, you could of course use any external CV. One example I
have seen uses the second channel of an analogue sequencer to control the 3031’s processor.

With an internal tbDAC, the user is not aware of any CV control. You just simply bang away
at your sequencer, or keyboard, and the velocity value of each MIDI note determines what
mode the 3031 drops into. 

ACCENT:

 When accent is triggered the VCA can become louder and more punchier. This

pot controls how much the accent has an effect. Like the TB303, the 3031 also modulates the
VCF with this signal.

VCA DECAY:

 The VCAs envelope can be changed from about 0.1s to about 3s with this

control. In other words it affects how long the note is heard after initial triggering.

OVERDRIVE:

 Adjusts how much the output waveform of the filter gets distorted. Fully

anti-clockwise gives an undistorted TB sound, while clockwise gives a heavily clipped

6

Summary of Contents for 3031 SuperBassLine

Page 1: ...Oakley Sound Systems 3031 SuperBassLine User s Guide V2 4 Tony Allgood B Eng PGCE Oakley Sound Systems PENRITH CA10 1HR United Kingdom...

Page 2: ...stors The PCB itself as well as being a different shape has been laid out for minimum noise and ease of construction The legending has been made clearer and its easier to interface to the tbDAC too Th...

Page 3: ...her midi controllers are not implemented and this makes controlling other 303 clones less intuitive Slides are often created by having to use legato notes But with a suitable midi CV convertor like th...

Page 4: ...d Many commercial clones have been criticised for not having the bite that the original had My spike circuit may well do the trick This like the TB303 slews the pitch CV before every new note for a sm...

Page 5: ...associated with normal square wave waveforms The sawtooth is far more bolder and harmonically rich but I think it still sounds better than the TB3030 s square wave FREQUENCY Alters the voltage contro...

Page 6: ...the velocity processor measures the value of the velocity CV and controls the synth accordingly Example velocity CV processor sensitivity Velocity CV Approx MIDI value Slide Accent 0 2V 0 31 no no 2 4...

Page 7: ...o want to use 5 types the please note that some of the resistors in the 3031 have to be 1 or better types Failure to use good quality parts in these locations will affect the VCO tuning stability and...

Page 8: ...49B and BC559B throughout in my prototypes The SCR in the VCO is different Here I have used BC212L and BC182L because when testing the prototype they gave better pitch stability I am unsure why this i...

Page 9: ...arts I can simply say that once fitted the KRL parts give much better stability over a wider range of temperatures Input and output sockets are not board mounted You can choose whichever type of socke...

Page 10: ...ired BUT this does depend on the power supply local temperature etc If you cannot hold the two power devices for more than 5 seconds after it is has been powered up for at least 10 minutes then you ne...

Page 11: ...72 R147 R148 R38 R46 R89 R115 R96 R95 R63 R65 R66 R62 R75 R134 R76 R64 R106 R117 100K 1 MF R9 16 100R R138 R139 R144 R93 R116 10K R32 R94 R37 R28 R13 R39 R53 R35 R36 R55 R141 R152 R150 R70 R102 R132 R...

Page 12: ...7 C28 C57 C60 C31 C42 C30 C25 C29 C21 C26 C49 220nF 63V polyester film C2 330pF low K ceramic C61 33nF 100V polyester film C51 C39 C38 C37 33pF low K ceramic C69 C62 C68 C63 3n3 63V polyester film C36...

Page 13: ...near regulator U10 CA3046 NPN array U8 CA3080 OTA U7 LM2901 Quad comparator U12 TL071 single FET op amp U3 TL072 dual FET op amp U1 U4 U16 U5 Pots All pots are Omeg E 16 or Piher P16 type 1MB VCA DEC...

Page 14: ...the board solderable for many years Please note this flashing is with solder that contains lead You should therefore wash your hands after handling the board and do not place the board or the solder i...

Page 15: ...I poke the leads through and then with about 4mm left between the bottom of the LED package and the board I cinch the leads to hold them in place when the board is upside down Be careful to get them...

Page 16: ...need to be matched up into the correct holes The 1583 has just five leads whilst the 3381 has seven The PCB has seven holes and they arranged in a staggered fashion on the board to match with the 2SC...

Page 17: ...he pots you can fit the board to your front panel Position the PCB at right angles to the panel the pot s own pins will hold it fairly rigid for now Then you can solder each of the brackets This will...

Page 18: ...eed and RS Electronics Ltd do have a range of rack units that may be suitable The Bryant Broadcast ones are superbly made but they do not allow you to use the 3mm thick Scheaffer front panel Their cas...

Page 19: ...higher rating Do not use a DC output type Although the latter are the most common type of wallwart for guitar effects pedals they will not work with the 3031 To reiterate because this is really impor...

Page 20: ...V convertor that was especially designed to interface with the TB3030 The new 3031 is even more suited to this interface thanks to clearer legending and simpler tuning set up You ll need to first buil...

Page 21: ...cable You can use a twisted pair instead if you wish This is just two wires tightly twisted together to form a simple cable Connect the tip connection of the jack socket to the OUT pad on the PCB Conn...

Page 22: ...a calibrated VCO and listen to the beats but that can take longer Plug your midi CV convertor or 1V oct keyboard into the CV input of the 3031 Play a lowish note on the keyboard then go two octaves h...

Page 23: ...r telephone me If you telephone then it is best to do this on Monday to Friday between 9 am and 5 pm British time And don t forget the Oakley Synths mailing group on Yahoo The link is on the Oakley we...

Page 24: ......

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