Constructional Difficulty: Easy
This is an updated version of the low frequency oscillator on the classic analogue synthesiser, the Korg MS-20. It features two output waveforms, triangle and square. But, the design also incoroporates a 'Shape' control that affects the rise and fall times of the triangle waveform, and mark-space ratio of the pulse waveform. Therefore, you can get sawtooth and reverse sawtooth from the triangle output by using the Shape control.
The Little LFO uses an integrated dual SPDT FET switch to enhance the Korg design. It also allows the use of waveform synchronisation. This is where the output waveform is reset back to zero when a SYNC pulse arrives from another module. If this SYNC pulse is the GATE output of a midi-CV convertor, then you can use the Little LFO as a linear repeating envelope generator.
A range switch may also be fitted to allow even lower frequencies to be made.
The phtograph shows the Oakley Triple-LFO. This features three Little-LFO PCBs in one 2U wide MOTM style panel. Powerful, yet extremely compact. Thanks to Colin Fraser for taking the photograph.
The issue 5 PCB
The PCB has been designed to fit within a 2U modular face plate. Three Little LFO boards can be fitted horizontally into this panel with all features provided. If you can do without the 'sync' and the LED, you can fit four LFOs in one panel. The size of a single board is 6.5cm wide and 4.6cm deep. (See, I told you it was little!)
It has two PCB mounted pots for RATE and SHAPE. The pots are spaced at 1.625". The pots are essential since these provide, along with the pot brackets, the only method of securing the PCB to the panel.
The PCB is double sided, has through plated holes, solder mask both sides and has full component legending. Power is admitted to the board via a single 4-way 0.156" connector, just like my other modules.
The pots used on this module are Alpha or ALPS 16mm types with a round bush. They use specially made pot mounting brackets to ensure a firm connection to the front panel and PCB. They are strong enough to hold the PCB in place without any further support.
The above photograph shows the rear of a triple LFO panel belonging to Andy Wilson. This particular unit features three of the older issue 3 boards with the Omeg E16 pots. The current issue 5 design uses Alpha 16mm pots and provides an additional power bus to make it easier to connect all three boards to the same power supply.
Project Downloads
Little LFO issue 5 User Guide
Use 'save as...' button to download and view the files. IE users need to right hand mouse click and then choose 'save as'. Links to schematics are available to purchasers of the PCB or module and will be sent via e-mail when the board(s) are shipped.
Front Panel database
A Schaeffer front panel can be made for a triple LFO module. The database can be found here: LFO-panel
To read this file you will need a copy of 'Frontplatten designer' from Schaeffer. The program also features on-line ordering, so its now even easier to buy your panels from Scheaffer.
The company are based in Berlin in Germany and will send out panels to anywhere in the world. Delivery to the UK normally takes around ten days. For North American users you can also order your Schaeffer panels from Front Panel Express.
Prices
Triple LFO ready made module................................ 135GBP
Little LFO pcb iss. 5
...................................................... 9GBP
Little LFO bracket kit......................................................
0.40GBP
The Little Lag pot kit contains the two pot brackets to mount the Alpha/ALPS pots safely to the board. The bracket kit does not contain the pots or the knobs.
All other parts can be purchased from you usual electronic component supplier.
Click here for full price list, ordering details, and payment methods.
All prices include VAT at UK rates. Shipping/postage is additional to these prices. See also the FAQ page.
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