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256e-md

![Buchla 256e](C:buchla_doc/static/img/200e/256e.jpg "Buchla 256e”)

The Buchla 256e

Quad Control Voltage Processor​

The Buchla 256e is a module that offers four identical versions of a powerful control voltage processing tool. Each of the four sections provides control voltage selection, multiplication, addition, scaling, inversion, and non-linear transformation, all in a simple, immediate, and visually-clear manner.

Input​

Each of the four sections has two inputs, marked "A1 in" and "A2 in." Using the knob above them, marked "A1 A2," you can select or mix the two input control voltages, fully left will give you only the A1 input, and fully right will give you only the A2 input. Anything in between will be a range of mix of the two input voltages.

There is a black banana jack that separates Input A1 and Input A2, and it is labeled "In Select." By introducing a control voltage to this jack, you are able to voltage-control movement between the two inputs.

If there is nothing plugged into A1, the section will multiply the control voltage at "Input Select," and the control voltage at A2.

The "Transfer Function" Screen​

This screen allows you to discern the settings for the "Output @ 0 Volts In," the "Output @ 10 Volts In," and the breakpoint settings.

"Output @ 0 Volts In," and "Output @ 10 Volts In"​

At default, the 0 Volts In knob is at zero, and the 10 Volts In knob is turned all the way up. This setting represents the situation where the input is as it is. If you set the 0 Volts to 10 and the 10 Volts to zero, the input signal is fully inverted. Setting these at various settings between zero and 10 will allow you to scale and shape your control voltages.

Breakpoint​

Since the relationship between the "0 Volts" dot and the "10 volts" dot on the screen can be described as "a line connecting them," the Breakpoint function allows you to create a more interesting voltage shapes that create more complex outcomes.

If you press the "Breakpoint" button, another dot appears between the 0 Volts dot and the 10 Volts dot, creating a more complex interpolated shape. Using the "in value" and "out value" knobs, you can place the breakpoint dot anywhere in the grid of LEDs between the 0 Volts dot and the 10 Volts dot, allowing you to control the behavior of the voltage. The "in value" knob moves the dot left and right, and the "out value" knob moves the dot up and down.

The breakpoint-related knobs are disabled when a breakpoint is not present.

Output​

The blue output banana jack in each section represents the result of the various settings in the section, and has an LED to indicate what is happening at that output.

Examples​

![256e Example 1](C:buchla_doc/static/img/200e/256e-1.jpg "256e Example”) The first example shows a setting that will give you exactly what you put in, in order to indicate a sort of "default" setting

![256e Example 2](C:buchla_doc/static/img/200e/256e-2.jpg "256e Example”) This example shows a setting that takes the product of two input voltages that is inverted. In this instance, as noted above, an voltage is directed to the "In Select" input, and a voltage is directed to the A2 input, resulting in a multiplication of those two voltages. The 0 Volts in is all the way up, and the 10 volts in is all the way down, resulting in an inversion of the input voltages.

![256e Example 3](C:buchla_doc/static/img/200e/256e-3.jpg "256e Example”) In this example, two input voltages, introduced to A1 and A2, are mixed. The 0 Volts In is increased. The 10 Volts In is at its maximum. As a result, there is a scaling occurring. The Breakpoint is activated and placed at the same level as the A1 input until it gets close to the 10 Volts In. This means that the mix of the two input voltages stays at a constant state until it hits that breakpoint, and the leaps up to the setting of the 10 Volts In.

![256e Example 4](C:buchla_doc/static/img/200e/256e-4.jpg "256e Example”) A control voltage is introduced to A1, and a control voltage is introduced to A2. The resultant voltage is set to vary back and forth between the two input voltages with a mix of them happening in the process of the variance due to the voltage introduced at "In Select." Since the A1/A2 knob is set all the way left, the entire voltage spread is available to this modulation. The 0 Volts In is near in voltage to the 10 Volts In, but the breakpoint is set low and near to the 0 Volts In, resulting in a short level of voltage, a great dip, and then a climb back up.

The Matrix​

While the matrix of LEDs is somewhat coarse, the actual voltages in the 256e are calculated to a high degree of precision; such that they can be applied to pitch and other applications requiring a level of accuracy.

##Preset Management and Remote Enable Knob and breakpoint values can be stored locally and later recalled when a preset is generated with the Preset Manager.

To connect or disconnect this module from the central library function, press "rem enable." A lit LED indicates that the module is connected.

Firmware Update​

Please note that this module actually contains two computers. When downloading or checking firmware, use breakpoint buttons A and C to download or check both sets of firmware instead of the rem enable button.