Related Manuals for Oakley Sound Overdrive 3U
Summary of Contents for Oakley Sound Overdrive 3U
- Page 1 Oakley Sound Systems 3U Oakley Modular Series Overdrive Soft and hard clipping module User Manual and Builder's Guide V1.1.3 Tony Allgood B.Eng Oakley Sound Systems CARLISLE United Kingdom...
- Page 2 Introduction This is the User Manual and Builder's Guide for the issue 1 Overdrive 3U module from Oakley Sound. This document contains a basic summary of its operation, a how it works section, a full parts list for the components needed to populate the board and some basic testing methods.
- Page 3 In fact, hard sync type sounds can be easily obtained by simply sweeping the filter's cut-off frequency. The Oakley Overdrive module for the Eurorack format. This module has been built by Krisp1.
- Page 4 The problem is that with some things it simply boils down to personal taste. I think the Oakley Overdrive is one such thing – it either produces a sound that you like or it doesn't. Furthermore, since it does very little other than overdrive the input signal it is a bit of a one trick pony.
- Page 5 However, it can be also used more subtly on more mellow filter sweeps with the overdrive adding gentle overtones to a solo synthesiser lead. The actual input level is very important too. The Overdrive module will produce much more strident results when the input level approaches 5V peak. If the input signal is too weak then the resultant overdriven effect will be much less.
- Page 6 Molex/MTA are +15V, ground, earth/panel ground, -15V. The earth connection allows you to connect the metal front panel to the power supply’s ground without it sharing the modules’ ground line. More about this later. As is common for our 3U series of modules the PCB has no mounting holes.
- Page 7 Components 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. Some special considerations for this project The op amps are any high quality dual audio op-amp. The design has been tested with OP275G, JRC4558, TL072 and OPA2134A.
- Page 8 3U Overdrive Parts List 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. For capacitors: 1uF = 1000nF. To prevent loss of the small ‘.’as the decimal point, a convention of inserting the unit in its place is used.
- Page 9 Onboard Pots All pots Alpha 16mm 47K Lin or 50K Lin BALANCE 100K Log GAIN 10K Lin TIMBRE The TIMBRE and BALANCE pots have space to mount pot brackets. Note that when fitting the GAIN pot, which has no pot bracket, a shim washer should be fitted between the pot and the inside of the front panel.
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Page 10: Circuit Description
However, I will leave it to the builder to experiment here and I am sure that the Oakley Sound Forum would be a great place to discuss your findings. The key in the basic TS overdrive circuit is the usage of a standard non-inverting high gain op-amp stage, U3A, with two diodes in reverse parallel with the resistative feedback path. - Page 11 In addition C9 will effectively block any DC signals to the amplifier. The Oakley Overdrive has a major difference that the original TS doesn't have. We can switch out the diodes completely and allow U1A to become an unlimited high gain amplifier.
- Page 12 The tone control is based around the classic TS and SD-1 design and is built around U3B. Its a simple circuit that works well in practice and produces enough tonal variation to be very useful. At the lowest setting of the Tone pot, called 'timbre' on the suggested front panel, C1 acts in conjunction with R10 to produce a single pole low pass filter.
- Page 13 Earth/panel metal -15V Note that the third pin is separate to the main module ground. This is the standard Oakley power specification and allows for the front panel to be grounded to earth at the power distribution board rather than locally through the module. However, other than in Oakley modular systems it is not widely used.
- Page 14 Use multistrand hook up wire to connect each socket lug to the relevant pin on the header. Keep your wires short but not too short and you can use as many different colour wires as you can – although I tend to use one colour because I'm a minimalist. There is absolutely no need to use screened cable for such short runs.
- Page 15 Testing, testing, 1, 2, 3... Apply power to the unit making sure you are applying the power correctly. Check that no device is running hot. Any sign of smoke or strange smells turn off the power immediately and recheck the polarity of the power supply, and the direction of the ICs in their sockets and the polarity of the electrolytic capacitors.
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Page 16: Final Comments
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.