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How To Make An EGG Mod

Article from Polyphony, July 1977

Most of you are probably familiar with PAIA's Chord Egg, a neat little device that both randomly changes chords and also randomly fades the individual notes of the chord selected in and out. The chords selected for the EGG's progression are C, F, and G major - a pretty good choice, when you consider that chord progressions based on these three chords are found in music from Bach, to blues, to country, to "Louie, Louie". It has a nice major feel, and has a generally cheerful effect on listeners.

However, there are other progressions. You certainly wouldn't want to use minor chords (take my word for it; listen to a minor chord progression repeated endlessly and you'll wonder what got you feeling so depressed!). But by modifying your EGG to give a B flat major chord instead of a G, you come up with a chord progression that is very popular, perhaps second only in popularity to the good ol' C-F-G we talked about earlier. It is an excellent progression for contemplative and meditative purposes, and gives more of a "suspended" feeling whereas the C-F-G is more "grounded". The trick is that we're implementing a minor based progression, but with all major chords. This gives you the best of both worlds.

So if you'd like to reprogram your EGG to alternate between C, F and Bb major, here are the steps to take:

1. Change R84 from 4.7K to 10K.

2. Remove R68.

3. Add a 10K resistor from the junction of R67 - R69 to the junction of R66 - R84 - R77.

4. Add another 10K resistor from the junction of R71 - R61 - R76 to ground.

5. Break the p.c. board trace between IC1, pin 14, and the cathode of D6. Reconnect D6's cathode to IC1, pin 13, using a short piece of insulated jumper wire (pin 14 remains unconnected). Well, that's all there is to it. With a four pole, 2 throw rotary switch, you can hook up this modification in such a way that you can switch between the standard C-F-G and the new C-F-Bb; see the diagram shown in figure (a).

One final hint: It seems to me that the C-F-G progression is the ideal daytime environment, and the C-F-Bb progression is more suited to night time. If you come up with any interesting thoughts about the connection between music and mood, I'd like to hear about it. Write me c/o Polyphony.

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Publisher: Polyphony - Polyphony Publishing Company

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Polyphony - Jul 1977

Donated & scanned by: Mike Gorman

Feature by Craig Anderton

Previous article in this issue:

> Patches

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> Sample & Hold Modification

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