Constructional difficulty: Small module with some simple setting up
Module Size: This module is designed for the Euro/Frac 3U high formats but will also fit into 5U with 20mm knobs.
Fractional Rack and Euro versions of the Oakley Classic VCA. The Frac is one frac unit wide. The Euro is 8HP wide.
This is a high quality single channel voltage controlled amplifier designed around an all discrete transistor core. It is based on the 4019 sub-module which is found in the classic 2600 semi-modular synthesiser.
Two signal inputs are provided, one DC coupled and the other AC coupled. The former allows audio and low frequency signals to be processed. While the latter provides a DC block to process only alternating frequencies. Both inputs can be used simultaneously and each one features an input level control.
The unit features both linear and exponential control voltage (CV) inputs. Both can be used together or individually.
A gain control is also available to provide a fixed bias to set the initial gain of the VCA. This way a negatively going CV can reduce the overall gain of the VCA. The gain pot can also be used a volume control.
Fractional Rack version (3U high, 1 frac unit wide)
The PCB
The PCB is double sided with through plated holes. It features solder mask both sides and is legended for easy construction. The board will allow for MOTM/Oakley, Frac and Euro power supply connectors. The module will run from either +/-15V or +/-12V. The board size is 79mm (deep) x 102mm (height).
The control pots are Alpha/ALPS 16mm types and for extra rigidity can be optionally mounted with matching brackets. Because the board is designed to mounted to the panel with the pots no other mounting holes are provided on the PCB.
The completed prototype Euro style module in a 10HP wide panel with sockets to the right of the pots
Prices
Euro Classic VCA Full Module.............................
90GBP
Frac Classic VCA Full Module............................. 90GBP
Completed modules come with two mounting screws and appropriate power lead.
Classic VCA issue 1 PCB
................................... 15GBP
Classic VCA issue 1 pot kit ................................. 5GBP
Classic VCA issue 1 pot bracket kit
................... 0-40GBP
THAT340P NPN/PNP array
................................. 6GBP
SSM2220 PNP array
............................................ 5-50GBP
The Pot Kit contains the correct type and quantity of 16mm Alpha potentiometers to complete one module. The Pot Bracket Kit contains the correct type and quantity of Alpha pot brackets required to complete one module.
You need one THAT340P and one SSM2220 per module.
Click here for full price list and ordering details. All prices include VAT at UK rates. Shipping and postage is additional to these prices.
Project Downloads
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 the 3U high 10HP module in standard natural finish. The database is available here. Note that the socket hole size is for Cliff 3.5mm sockets.
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.
3U high 10HP wide panel for Euro sized modulars
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