Construction Difficulty: Moderate
The suggested front panel for the Oakley Triple VCA. The panel size is a standard 2U width.
One can never have enough voltage controlled amplifiers (VCA) in a modular synthesiser. The VCA allows you to control any signal, be it CV or audio, with another control voltage (CV).
In the typical application one uses a VCA to shape the volume of the final output signal of the synthesiser. But a good VCA can do much more.
The Oakley VCA module consists of three high quality voltage controlled amplifiers (VCA) suitable for audio and CV. This design uses standard parts in a very unconventional manner to give a superb sounding VCA with low noise and the minimum of CV breakthrough. Unlike my older 'Basic-VCA' design, all three VCA sections are one board to facilitate quick and troublefree building.
Each VCA has two controls. Firstly, there is GAIN, a fixed bias to set the initial gain of the VCA, it can also be used a volume control. Secondly, the CV pot allows you to alter the sensitivity of the external CV that controls the VCA's gain.
The PCB
The PCB is double sided, has through plated holes and component legending. The size is 108 x 108mm. The three 'gain' pots fit direct to the PCB and are supported by pot brackets which also hold the PCB to the front panel. Four mounting holes are provided for use with other mounting techniques.
This is the current issue 2 Triple-VCA board in the standard 2U panel. Notice the three CV depth pots fitted with 'potchip' mini PCBs, and the interconnections done with pre-made 0.1" jumper leads.
Prices
Triple VCA issue 2 PCB
.................................................. 17GBP
Triple VCA pot kit
............................................................. 18GBP
Triple VCA pot bracket and pot chip kit
........................... 6GBP
The Triple VCA pot kit contains six Spectrol 248 pots sufficient to make up one 2U wide panel. No knobs or switches are provided. The Triple VCA pot bracket and pot chip kit contains three Oakley pot brackets, three potchip PCBs and six extra pot nuts. The brackets are especially made for us to hold the PCB mounted Spectrol pots safely to the PCBs and cannot be purchased anywhere else.
All other parts can be purchased from you usual electronic component supplier.
See the prices page for ordering information, shipping charges and payment methods.
All prices include VAT at UK rates. Shipping/postage is additional to these prices. See also the FAQ page.
Project Downloads
Issue 2 User Guide and Parts List
Use 'save as...' button to download and view the file. 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
The new MOTM compatible front panel database is here: VCA 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.
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