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Oakley Sound Systems
3031 SuperBassLine
User’s Guide
V2.4
Tony Allgood B.Eng PGCE
Oakley Sound Systems
PENRITH
CA10 1HR
United Kingdom
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Introduction The Oakley 3031, pronounced as 'thirty-thirty-one', is a heavily revised edition of the hugely popular TB3030 project. It is designed to be built into a 1U 19" rack. All the thirteen knobs, the four switches and the four LEDs are designed to be mounted directly onto the printed circuit board. This simplifies building and reduces the possibilities of any mistakes in construction. There has been some revision of the circuitry compared to the TB3030. Gone is the old 4013 based sub-octa
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connected to the mixing desk, or whatever, without ground loops occurring. Either use a full balanced connection or a semi-balanced connection. 2. The 3031 features a rather useful distortion circuit, with a depth control. Excellent for a harder sound. If you think you are not into distortion, this circuit will surprise you. 3. The VCF’s cut-off frequency can be controlled by an external CV. In the standard format, this CV can come from either the velocity CV or modulation wheel CV. Both these C
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the tbDAC. The gate is ON when above 3V. A new schmitt trigger circuit is provided for glitch free triggering. 10. Accent Decay has been provided. The original TB303 produces a fixed short decay time when accented. This control allows you to alter it, up to the time set by the ordinary decay pot. 11. VCA decay. The TB303 has a fixed VCA decay of about 3 seconds. This control allows you to change it to some time between 0.1s to 3s. 12. Power supply. The 3031 comes with a very low noise stable all
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Operating Instructions The following will be a description of the pots and switches in the 3031. Refer to the diagram at the end of this document for a drawing of the front panel. Reading the front panel for the 3031 from left to right: TUNE: Alters the frequency of the VCO and thus tunes the whole instrument. SLIDE: Controls the amount of portamento on the pitch when the note changes and slide is enabled. The little red LED will light if the slide is active. VCO WAVE: The VCO produces two basic
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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 t
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waveform. This will emphasise certain higher harmonics. Use this in conjunction with the resonance pot and you can get good approximations to hard synchronisation. VOLUME: Controls the final output level. The 3031’s output level is very high and is similar to the output of pro-audio equipment. Components Most of the parts are easily available form your local parts stockist. I use Rapid Electronics, RS Components, Maplin and Farnell, here in the UK. The 3031 was designed to be built solely from p
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The ceramic capacitors should be ‘low-K’ or C0G ceramic plates. The lead spacing is 0.2” or 5mm. Do not chose cheap and nasty ceramic types, usually ‘high-K’, obtainable from some surplus places. These can lead to a noisy audio output. The horizontal preset or trimmer resistors are just ordinary carbon types. No need to buy the expensive cermet types for these positions. Carbon sealed units have more resistance to dust than the open frame types. Piher make a suitable type to use here. Pin spacin
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I do still use the 2SK30A-Y in the 3031. The Y types are still produced by Toshiba and are easily available. I also use the 2SK30A-GR too. This is used in the FET buffer for the new VCA circuit. A Y type may be used in its place, and either may be provided in the ‘odd parts’ kit. The original Japanese NPN pair is the 2SC1583. It is a superb component and although not made any more is still readily available in most places. Matched pairs are required in two places in the 3031, the exponential con
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The VCO wave switch is an ON-ON type, but is a two pole (2P) switch. This essentially means that there are two switches internally controlled by one toggle. These are sometimes called DPDT or double pole-double throw. The manufacturer’s part numbers for the chosen switches are: SPDT On-On 7101MD9AV2BE SPDT On-Off-On 7103MD9AV2BE DPDT On-On (2P) 7201MD9AV2BE Note that C&K are now part of the mighty ITT-Cannon organisation. The ‘filter control’ switch may be obtained from Farnell, part number: 917
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Parts List I strongly advise you to read the Components section above before you place any order for parts. A quick note on European part descriptions. 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. Resistors All 5% 1/4W carbon or better except where stated. Some values need to be 1% 1/4W metal film (MF) types or better. * denotes tbDAC optional value chang
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470K R85, R24, R79, R78 47K R124, R2, R149, R68 47R R166, R156 4K7 R48, R61, R151, R45, R44 56K R25 5K6 R143 68K R43, R112 6K8 R21 75R R158, R170 82K R69 82K 1% MF R8, R9* Capacitors 1000uF, 35V elect C54, C48 100nF, 63V polyester film C50, C52, C13, C44, C22, C19, C64, C71, C4, C34, C40 10nF, 100V polyester film C11 10nF 1% polystyrene C9 10uF, 35V elect C12, C55, C58, C45, C3, C1, C20, C18, C65, C67, C56, C32, C24, C43 150pF low-K ceramic C16, C6 15nF 100V polyester film C15, C35 1nF, 100V po
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1N4002 diode D26, D25, D22, D24 J201 J-FET Q5 10V 400mW zener diode D11, D10, D9 2SK30A-GR or -Y J-FET Q19 2SK30A-Y J-FET Q37 TIP31A NPN power Q42 Integrated Circuits You should consider IC sockets for all of the DIL ICs. You need six 14-pin DIL, and six 8-pin DIL sockets. 2SC3381 or 2SC1583 U6, U9 4066 quad analogue switch U2, U11 4093 quad schmitt NAND U13 NE5532 dual audio op-amp U15 LM723 linear regulator U14 7912 -12V linear regulator U10 CA3046 NPN array U8 CA3080 OTA U7 LM2901 Quad
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SPDT SW3, SW5 SPDT (on-off-on) SW4 DPDT SW1/2 Miscellaneous Case, front panel, sockets, mains/power socket, wall-wart power supply/ transformer, connecting wire, knobs, fuse holder (for mains supply). Populating the PCB Occasionally people have not been able to get their Oakley projects to work first time. Some times the boards will end up back with me so that I can get them to work. To date this has happened only four times across the whole range of Oakley PCBs. The most common error with three
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18W one for this purpose. I use an ordinary Antex 25W iron with a Variac power supply running at 205V. This seems to work well for me. All resistors, apart from the special PTC, should be flat against the board surface before soldering. It is a good idea to use a ‘lead bender’ to preform the leads before putting them into their places. I use my fingers to do this job, but there are special tools available too. Once the part is in its holes, bend the leads that stick out the bottom outwards to ho
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underneath the body of transistor. Turn the board over and cinch the two outer leads on the flip side, you can leave the middle one alone. Now solder the middle pin first, then the other two once the middle one has cooled solid. Cut off any excess leads. Sometimes transistors come with the middle leg preformed away from the other two. This is all right, the part will still fit into the board. However, if I get these parts, I tend to ‘straighten’ the legs out by squashing gently all the three of
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bend the lead firstly near the body of the device at an angle of 45 degrees. Then where the metal leg thins, I bend it again so that it becomes parallel to the other two. The device should then fit snugly into place on the board. Whenever you need to bend legs of any semiconductor device be gentle. Its a good idea to earth yourself too. Touching a nearby radiator or oscilloscope earthing tag is usually enough. IC sockets are to be recommended, especially if this is your first electronics project
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With panel removed once again, you can now fit the switches. The C&K PCB mountable switches should fit tightly into their respective holes on the board. Make sure the ‘on-off-on’ switch goes into the ‘filter control’ location. You may need to use a pair of fine nosed pliers to help the flexible gold pins into the board holes. Make sure the switch body is flat against the board. Now refit the front panel and make sure the round switch barrel fits into its hole in the front panel. Now solder all t
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For those of you fitting an internal toroidal transformer. Please, please make sure there is no way the top metal disc of the transformer's mounting can touch the top of the casing. If the metal support of transformer together with the case makes a complete loop around the core, then you have a shorted one turn secondary. (‘well, there was a large hum, more of a buzzy rattle really, then a smell of burning rubber and then a lot of smoke... ’). You may also like to consider the use of a nylon bol
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The following advice is only for those who know how to wire mains rated equipment safely. If you do not know how to do this then make no attempt to do so. I do not endorse this method of powering any Oakley equipment. It is up to you to use your PCB wisely. I take absolutely no responsibility for your actions with this board. I will offer no further advice than what you see below in italics: Transformer rating: Secondaries: 12-0-12 @ 250mA or 12-0, 12-0 @ 6VA total Connect common, or centre tap
