CESYG DUALFO USER MANUAL CESYG DuaLFO Installation and User Manual Document CE-101-0002 Page 1
CESYG DUALFO USER MANUAL DUALFO Installation and User Manual Copyright © 2012 Neil Johnson First edition, May 2012 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the author. CESYG c/o Neil Johnson 120 Lovell Road Cambridge CB4 2QP United Kingdom Web: http://www.cesyg.com Email: info@cesyg.
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CESYG DUALFO USER MANUAL Contents 1. INTRODUCTION Special Features 2. SPECIFICATION 3. INSTALLATION Unpacking Installing the Power Cable Main LFO Normalising Options Installing the DUALFO Power-on Test 4. ADJUSTMENTS Shape Maximum Bias Trim (VR1) Sine Shape Trim (VR2) 5. USING THE MAIN LFO Output waveforms Controls Applications 6. USING THE AUXILIARY LFO Output waveforms Controls Applications 7. NOTES 8.
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CESYG DUALFO USER MANUAL 1. INTRODUCTION This manual describes the installation and operation of the CESYG DUALFO two-channel low-frequency oscillator (LFO) for the Eurorack modular synthesizer system.
CESYG DUALFO USER MANUAL Special Features The DUALFO has been designed and constructed with care and attention to detail: - The SYNC edge switch is a high-quality ALPS SPUN push switch, the same type as commonly found in many mid-range British audio mixing consoles (maybe not Neve or SSL, but definitely Allen+Heath, SoundCraft, and SoundTracs). - A Dual Earth system, similar to that employed by MOTM and Oakley, is used to separate the internal power and signal ground from the front panel and jack ground.
CESYG DUALFO USER MANUAL 2. SPECIFICATION Main Oscillator Frequency range: Approx. 200uHz (approx. 90 minutes) to 45Hz Outputs Waveforms: Three phase-related sinewaves at 0°, 120°, 240° Level: 10Vp-p output centered about 0V (typ.
CESYG DUALFO USER MANUAL Controls: Shape: Manual frequency control, log scale External CV control of frequency, with unipolar attenuator External sync input, with switchable positive or negative edge sensitivity Manual control over 10% to 90% range, centre 50%. External shape modulation over the range -5V to +5V, manual control operates as bipolar attenuator (left = negative, right = positive).
CESYG DUALFO USER MANUAL 3. INSTALLATION Fitting the DUALFO into your modular synthesizer is a straightforward task. This section describes the basic steps in unpacking and installing your DUALFO and a first initial power-on test. Unpacking The DUALFO comes packed in anti-static packaging. Do not open the packaging until you are ready to install the module in your modular synthesizer. As well as the DUALFO you should find this manual, a 16-way power cable, and a bag of M3x6mm screws.
CESYG DUALFO USER MANUAL Hold the DUALFO in one hand and insert the other end of the power cable into the power socket on the DUALFO, located at the bottom edge of the rear of the PCB. Both the header and the connector are polarised to ensure that they can only mate one way.
CESYG DUALFO USER MANUAL Main LFO Normalising Options Before fitting the DUALFO into your synthesizer there is an on-board link option. This sets the source of the normalised CV input of the main oscillator. The default position sets the source to the sine wave output of the auxiliary oscillator. You can change the link to select the CV line on the power bus. The link is located just above the power connector: Installing the DUALFO Now fit the DUALFO into your synthesizer.
CESYG DUALFO USER MANUAL the frame and fit the four M3 screws supplied to hold the DUALFO in place. Tighten the screws, but do not over tighten them. The recommended torque is 1.0Nm. Note: if your rack rails are made to accept M2.5 screws you must either supply them yourself, or they were provided with your DUALFO as a special option, or you can purchase them either from CESYG or elsewhere. Power-on Test Refit the AC power cable to your synthesizer.
CESYG DUALFO USER MANUAL 4. ADJUSTMENTS There are two adjustments on the DUALFO, both related to the Auxiliary LFO. Shape Maximum Bias Trim (VR1) The maximum range of the effect of the Shape control can be adjusted. During assembly this is set to approximately 10% to 90%. Sine Shape Trim (VR2) The Auxiliary sine wave output is derived from the triangle waveform using a diode shaper. VR2 can be used to fine-tune the shape of the sine wave to minimise distortion.
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CESYG DUALFO USER MANUAL 5. USING THE MAIN LFO The Main LFO provides three sine wave signals, ideal for providing spatial modulation or pseudo-stereo effects. Or, together with a 2-channel mixer, you can generate two sine waves with any phase offset you require in the range 0 to 360 degrees. Output waveforms Each of the three outputs of the Main LFO is a low-distortion sinewave. The three outputs are at fixed phase offsets of 0, 120 and 240 degrees.
CESYG DUALFO USER MANUAL The CV jack is normalised to one of two internal signals: the internal bus CV or the Auxiliary LFO sine wave. When no jack is inserted into the CV socket then the normalised signal is fed into the CV input and treated in exactly the same way. Applications The three outputs of the Main LFO can be used separately - for example, to generate pseudo-stereo rotation - or combined to generate a sine wave of any desired phase offset.
CESYG DUALFO USER MANUAL Now take a look at the phase diagram (end of manual). An arrow at the 90 degree position lies between the 0 degree and 120 degree arrows, so we need some mix of these two sine waves to produce the required 90 degree one. As the 90 degree arrow is closest to the 120 degree arrow we start with 100% of the 120 degree sine wave. Then, note that the 90 degree arrow crosses the dashed horizontal line - this corresponds to the 0 degree sine wave.
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CESYG DUALFO USER MANUAL 6. USING THE AUXILIARY LFO The Auxiliary LFO complements the multiple outputs of the Main LFO with a much greater degree of control over the shape and behaviour of its single output. Output waveforms The Auxiliary LFO internally generates a very precise triangle wave. This is provided as one of the two outputs. The second output is a diode-shaped sine wave, with distortion below 2%. The shape of the triangle wave (and also the sine wave) can be modulated internally or externally.
CESYG DUALFO USER MANUAL CV The CV control determines how much of the signal fed to the CV jack is used to modulate the Auxiliary LFO frequency. The control provides a linear scale, from 0% (fully anti-clockwise) to 100% (fully clockwise). SYNC The Sync input can be used to synchronise the Auxiliary LFO to an external trigger signal. The push button allows you to choose whether to synchronise to the rising (positive) or falling (negative) edge of the trigger signal.
CESYG DUALFO USER MANUAL Applications The Auxiliary LFO is a versatile modulation source. Main LFO Modulation Source The natural use of the Auxiliary LFO is to provide frequency modulation for the Main LFO. This is made through the optional internal normalising from the Auxiliary sine wave output to the Main CV input. The Shape control then comes into play to vary the profile of the frequency modulation of the Main LFO, with dramatic full sweeps with the Shape control at either extreme.
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CESYG DUALFO USER MANUAL Slowly Evolving Sound Textures The slow rates that the Auxiliary LFO can achieve make it useful for creating slowly evolving sound textures. Parameters that could be modulated to varying depths include VCO detuning or unison (multiple VCO) spreading, stereo or 3D panning, filter cutoffs, and so on. In addition, synchronising the Auxiliary LFO to a start pulse will ensure repeatable performance results.
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CESYG DUALFO USER MANUAL 7. NOTES The pages in this section are intended for you to make your personal notes on operating the DUALFO. The diagram pages are intended for you to photocopy or scan and print so that you can record patch settings and phase diagrams.
CESYG DUALFO USER MANUAL PATCH SHEET Name: ..............................................................................................
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CESYG DUALFO USER MANUAL 8. WARRANTY AND SERVICE Your DUALFO comes with a 12 month warranty from the date of first sale. If your DUALFO requires repairs resulting from a manufacturing defect you can return it to CESYG, at your cost, where it will be repaired or replaced and returned to you. Any damage caused by user negligence is not covered by this warranty. Such damage may include, but is not limited to, abusive usage, fluid spills, excessive voltages on inputs and/or outputs.
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