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227e-md

The Buchla 227e

The Buchla 227e

System Interface​

The 227e is a four-channel quadrophonic mixer with voltage-controlled quadrophonic panning controls for each channel. Settings for each channel are able to be saved in a preset. The mixer also includes output equalization and a four-channel sub-mixer whose output can be included in the main outputs, or it can be used independently. A pre-amplifier with XLR input and amplitude envelope-following functionality is also included.

Channel architecture​

Each channel has a tinijack input. The amplitude of the signal connected to that input is controlled by a large blue level knob.

There are two panning control knobs in the "SPATIAL DYNAMICS" section labeled "rate" and "ampl." The "rate" knob controls the left-right panning. The "ampl" controls AB-CD (front-rear) quadrophonic panning. Using these panning controls, you can quadrophonically place or pan your signal.

Beneath the Spatial Dynamics knobs, there are banana inputs so that these panning options can be voltage controlled. In order to activate the control voltages input to the banana jacks, the knobs must be turned fully clockwise. If the spatial dynamics knobs are not turned fully clockwise, the input voltage control will have no effect; similarly, if you turn either knob fully clockwise without a voltage input, you will not get expected panning results.

If you are only using the AB or CD outputs, the "ampl" knob can be used to control or voltage control amplitude of the signal.

The "swirl" button activates a behavior of dynamic panning in quadrophonic space. Control of the rate of this panning can be achieved by adjusting the "rate" and "ampl" knobs.

"Rate" controls the rate and direction of the "swirl." It is possible to mix in CV control to the effect, with the control strongest at fully-clockwise. Fully counter-clockwise means the CV input has no control

"Ampl" determines the intensity of the effect, with fully counter-clockwise being a static sound, and fully clockwise resulting in the sound traveling around all of the speakers. As a result, unlike the "rate" settings, fully counter-clockwise gives the most effect from the CV input, and fully clockwise results in no input from the CV input.

Mike Preamp​

The input of the Mike Preamp is an XLR input present on the breakout panel that is included with the 227e.

The gain of the preamp is controlled with the grey knob (the grey cap indicates that this is a setting that will not be stored in the presets saved in this module) found in the Mike Preamp section. A button below this knob allows amplification by 10dB, 25dB, or 40dB.

The blue banana jack is an output with voltages that are generated by the amplitude envelope of the input. Using the LED meter, you can set the input to an acceptable level.

The Mike Preamp has two tinijack audio outputs that output the same signal.

The Sub-Mixer​

The Sub-Mixer has four channels that are directed to the outputs. Each output contains the same mono signal. The gain knobs for each channel are grey-topped, meaning that their settings are not stored in preset information.

If the "in the mix" button is activated, an LED will light, and the output of each channel of the Sub-Mixer will be directed to the main output channel it is labeled with; Sub-Mixer channel A will only be heard in the output channel A, etc.

The Master Equalization and Levels​

Stereo channels AB (front) and CD (rear) each have a master equalization function containing a bass amplification/attenuation, a treble amplification/attenuation, and a "spectral tilt" amplification/attenuation. Spectral tilt is a means of addressing the intensity of high-frequency content. There are also knobs to set the overall levels of AB (front) and CD (rear). If you don't seem to be getting output from your channels, this is the first place to check.

Headphones​

The stereo headphone jack comes with features a dedicated output level control knob, and the ability to monitor AB (front), CD (rear), or both simultaneously… allowing the monitoring of quadrophonic channels within the context of stereophonic sound.

The 227e Breakout​

The 227e comes with a breakout that connects to the 227 via a 10-pin ribbon, and a 3-pin Molex connector. The breakout panel contains the XLR input for the Mike Preamp, as well as four quarter-inch jacks that represent the A B C D outputs. The breakout screws into the breakout port in a Buchla boat.

Remote Enable​

To connect or disconnect this module from the central library function, push the "remote enable" button. Connection results in the LED being lit.

The settings of the switches, the blue knobs, and the "in the mix" button can be stored in a preset using the Preset Manager present in the 225e or 206e.