Buchla 208C Music Easel 4U Module User Guide

Buchla 208C Music Easel 4U Module

Product Information

Specifications

• Model: 208C Stored Program Sound Source
• Compatible with Music Easel instrument
• New 218 Touch Activated Voltage Source with additional patch points
• MetaProgramming capabilities
• Conductance Level Resistance Color Code:

Product Usage Instructions:

Programming with 208C Sound Source Module:
Utilize the stored program capabilities to expand your Music Easel instrument’s vocabulary. Refer to the manual for detailed instructions on utilizing the new opportunities.

Touch Activation with 218 Voltage Source
Explore the additional patch points of the 218 Touch Activated Voltage Source for unique modulation possibilities. Experiment with different connections to enhance your music creation process.

MetaProgramming Features
Take advantage of the slightly different resistor values in the current Music Easel for metaProgramming. Understand the resistance color code to customize and fine-tune your soundscapes.

Frequently Asked Questions (FAQ)

• Q: Can I use the 208C Sound Source module with other synthesizers?
  A: The 208C module is specifically designed to work with the Music Easel instrument and may not be compatible with other synthesizers.

• Q: How can I reset the settings on my Music Easel?
  A: Refer to the manual for instructions on resetting the Music Easel to its default settings. This typically involves specific button combinations or menu options.

• Q: What is the advantage of modulating the arpeggiator speed?
  A: Modulating the arpeggiator speed can add dynamic rhythmic variations to your music, creating more engaging and evolving compositions.

Programming

(In The Modern Age)
The modern 208C Stored Program Sound Source module brings a variety of new opportunities to expand your vocabulary with the Music Easel instrument. While the 208C manual details these differences, it is worth briefly noting them here.

• Patch points to modulate attack, sustain, and decay
• Independent tini-jack audio from complex and modulation oscillators
• Gate 1 input to replace complex oscillator as gate 1 source
• White noise option for gate 2 input
• Audio rate FM input for modulation oscillator
• CV input for modulation oscillator, or modifiable for modulation of sequencer steps
• CV control of waveshape
• The “off-ext” switch position for pulser allows external pulses to drive the pulser through the CV jack

The new 218 Touch Activated Voltage Source has some additional patch points distinct from the original Music Easel and the 2013 reissue.

• The new Touch Strip outputs a control voltage and pulse
• The green Velocity output provides per-note velocity voltage
• The Arpeggiator’s rate can be modified with CV, creating unlikely rhythms
• The Preset Voltage Source pads output a pulse, along with the knob voltage
• MIDI sync for Arpeggiator

While these new details are obviously not part of the original “Directive,” they can easily be incorporated by following Allen Strange’s encouragements to explore and, above all, be musical!
For example, modulations of the arpeggia-tor speed will no doubt excite the rhythmic sense, which can be augmented in performance by driving the pulser with independent taps of the touch strip!
Modulating the frequency of the modulation oscillator using the audio from the complex oscillator provides a new timbral landscape of feedback, controlled by the m.o.’s
“f.m. in” knob. It’s a simple connection that adds a variety of possibility.
Control voltage into the envelope’s time parameters is a very attractive means to creating generated soundscapes. The enve-lope can vary over time while looping, creating constantly shifting changes in volume and timbre.
Engage and explore: The Easel is prepared to create new sounds and music!

Meta- Programming
(In The Modern Age)
The current Music Easels uses some slightly different resistor values than the original.

• Conductance Level Resistance Color Code
• 10 120KΩ Br.-Red-Ye.
• 9 133KΩ Br.-Or.-Or.-Or.
• 8 150KΩ Br.-Gr.-Ye.
• 7 174KΩ Br.-Vi.-Ye.-Or.
• 6 200KΩ Red-Bl.-Ye.
• 5 240KΩ Red-Ye.-Ye.
• 4 300KΩ Or.-Bl.-Ye.
• 3 390KΩ Or.-Wh.-Ye.
• 2 560KΩ Gr.-Blu.-Ye.
• 1.5 820KΩ Gry.-Red-Ye.
• 1 1.2 MegΩ Br.-Red-Gr.
• 0.5* 2.2 MegΩ Red-Red-Gr.
• 0.25* 4.7 MegΩ Ye.-Vi.-Gr.

*Values <1 are generally for adding to others.

The principles for wiring up a program card are the same as they were in 1974. We’ve added some additional images in the following pages that should make it easier to find the correct resistor values and understand how to make connections. With these additions, we hope to make the process of making the retro program cards more fun and accessible. Scan the QR codes on the following pages to download a printable version of the page.

Figure 22 illustrates the relationship between the switch settings on the 208C’s controls, the resistor values required to match those controls, and where the resistors are placed on the Retro Program Card. In most cases, the value of the resistor sets the switch position. However, with the PULSER and ENVELOPE switches, the resistor serves to set the position and the mode.
Figure 23 translates a simple patch chart of slider values into resistors on the Program Card. Unlike patch cords on the 208C that provide a simple connection to a modulation amount slider, the resistors indicate both the presence of a patch cord connection and the amount slider when used on the Program Card. An additional resistor is used to describe the offset for a modulated parameter. For example, in the image, you can see the SEQUENCER voltage is used to modulate pitch only a small amount (an index of 0.5), but the COMPLEX OSCILLATOR pitch is offset with a conductance value of 3.
Figure 24 provides a visual guide of the band colors and their values to help you keep track of your resistors.
It is worth noting that for most modern 208 modules (2015 and later), the 5th step and 5th sequence voltage are always 0 on the Program Card, and the card should remain unpopulated with resistors in those locations.
The Worksheets provide tables and a patch connection matrix that help track your connections, switch, and slider positions to create an inventory of all the resistors needed for your Program.

Switch Position Worksheet

Fader Position (Offset) Worksheet

Patch Connections Matrix

Fill in a CV amount to modulate a destination with a source. For example, if you have a patch cord connecting sequence to level 2 with an amount of 5, write “5-240kΩ” here.

Buchla Music Easel Patch Chart Patch Name
Author:
Date:

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