I was intrigued by the story of the release of George Harrison‘s album ‘Electronic Sounds’ and the involvement of Bernie Krause. And after doing some more investigation I found out that the Beatles did use a (Moog) synthesizer more often then I thought.
I found a copy of the book The Beatles as musicians by Walter Everett and did find some references to the Moog synth, and the Bernie Krause story.
Below you can find some of the parts that discuss synthesizer and electronic (effects) music in the Beatles recordings.
Such as the part where Harrison talks about the first introduction to the Moog synthesizer (p 208). One of the side benefits of the recording project of Jackie Lomax’ Is this what you want was the introduction to the Moog synthesizer by Paul Beaver and Bernie Krause.
This part (p 242) is about the involvement of ‘Moog Pioneer’ Bernie Krause during these recording Lomax sessions. We are talking 1969. After hearing the Moog synthesizer George Harrison ordered one immediately – and a Sequencer complement B followed later.
The demonstrations of the Moog synth by Krause were recorded and released on without the knowledge of Krause.
(p 242) The solo LP by George Harrison was Electronic Sound (United Kingdom: Zapple 02, May 9, 1969, not charting; United States: Zapple ST3358, May 26, #191). Playing with studio test equipment once in March 1967, McCartney had told an EMI engineer that someone should connect a bank of oscillators with electronic controls: “It would be a new electronic instrument.” 60 In fact, Robert Moog was developing just such an instrument, the modular synthesizer, at that time.
(p 245) About the usage of Harrison’s Moog IIIp in the recording of the ‘White’ album and the fact that this instrument had to be treated differently from guitars and drums in the recording process. Synth’s don’t go through amplifiers usually 🙂
(p 252 McCartney added five different Moog parts to the recording of ‘Let it be’ …
(p 255) Lennon added white noise from the Moog (right; “growing” out of the crash cymbal and most audible after 5:42)
(p 258) ….represents the brightening sun in the bridge by the Moog motive that rises in register and culminates in a V7 -prolonging retransition highlighted by brilliant frequencies in piccolos and well-placed cymbal crashes. The middle section features a patch probably based on a sawtooth wave, realized as the motive sounds in four different registers. With each higher octave, the edge of the sawtooth seems dulled a bit, approaching the purity of a sine wave but not so much that its last appearance, which concludes on a2 in the opening of the fifth ending, doesn’t lead perfectly to the bright attack of the piccolos on g#2 one bar later. A second patch, seemingly based on a triangle wave and featuring a light ribbon portamento, was used in two other passages ….
The “horn” patch probably added some noise alongside the sawtooth, and both sources were led to voltage-controlled low-pass filters regulated by separate envelope generators. This would have allowed the noise to have a faster attack and decay than the slower-to-open, longsustaining sawtooth would have. It may also have had a bit of regeneration to simulate the horn’s natural resonance around 500 Hz and a touch of reverberation. The second and third patches sound simultaneously in the song’s conclusion (2:12 to the end); on the left, an envelope generator with a slow attack regulates a low-pass filter, causing the upper partials to open up in sequence on each note, and a simple trianglelike wave is heard on the right channel.
(p 303 … Considering the Beatles’ great interest in electronic keyboards, the Moog was a natural for them. Each Moog module, itself equipped with potentiometers and/ or switches to regulate its effect, is capable of altering an incoming voltage. The resulting controlled voltage can then be applied by a patch cord to another module, controlling the effect of that oscillator, filter, or
amplifier on a second incoming signal ( along either linear or exponential scales). Thus, an oscillator might generate, from the incoming power supply, one of several basic periodic waveforms: a single frequency (ranging from 100
to 15,000 Hz) approaching a pure sine wave, or a preset combination of harmonic partials above a fundamental frequency producing various timbres,
such as the flutelike triangle wave, the clarinetlike square wave, or the buzzlike sawtooth wave, or combinations of nonharmonic frequencies…..
Few knew what to make of it then, and the imaginative track has since never caught on among Beatles fans not otherwise interested in electronic music. (The techniques did not appreciably influence other rock musicians either; the atonal synthesized music and the musique concrete heard on Jerry Garcia’s first solo album Garcia  were probably inspired more by ex-Dead keyboardist and Stockhausen student Tom Constanten, as demonstrated on Anthem of the Sun . In September 1998, theorist Jonathan Bernard and I shared mutual memories of theBuckinghams in 1967-68, and these conversations led to the uncovering of a number of electronic images in their works, created by their Varese-inspired producer, ex-Mother Jim Guercio.) As Lennon was to later complain that one reason he left the Beatles was his discomfort in having to fit into some kind of “format;’ the 1968 arguments over the tempos of “Revolution” and whether or not to include “Revolution 9” on the White album may be seen as portents of the rejection a year later of a “Cold Turkey” single and of the McCartney- dominated arrangement of the Abbey Road LP. Lennon was soon to think that if Beatles fans didn’t care for “Revolution 9;• he could find his audience elsewhere.