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2.2: Sound Sources: Oscillators and Noise

The EMS Putney, or EMS VCS 3, features a unique set of sound sources that contributed to its distinctive sonic character. Here’s a description of the oscillators and noise generator found in this iconic synthesizer:

Voltage Controlled Oscillators (VCOs):

The EMS Putney is equipped with three VCOs. These oscillators generate audio waveforms, and they each have their individual characteristics.

VCO 1 produces a sine wave and a sawtooth. It can be precisely tuned and modulated.

VCO 2 generates triangular and square waves. It has a wider pitch range and can also be finely tuned and modulated.

VCO 3 is different from the first two oscillators. It generates audio-rate and low-frequency oscillations (LFO) in various waveforms.

The three oscillators of the Putney at Willem Twee Studios are modified with an extra toggle switch, so all oscillators can be switched from audio rate to LFO rate.

Noise Generator:

The noise generator on the EMS Putney produces various types of noise that can be used for a variety of sound effects and textures.

White Noise: This is the classic “hissy” noise, which contains all frequencies equally. It’s often used for adding background noise, percussive sounds, or as a source for shaping other sounds.

Pink Noise: Pink noise has equal energy in each octave, which makes it sound more balanced across the frequency spectrum compared to white noise. It’s often used for filtering or creating natural sound effects.

The combination of these sound sources, along with the extensive modulation capabilities and the unique patch-based routing system, allowed musicians and sound designers to create a wide range of sounds and textures on the EMS Putney. This flexibility, along with the inherent quirks and character of the instrument, contributed to its legendary status in the world of electronic music

Filter as an Oscillator:

the filter in the EMS Putney, actually a “treatment,” is a unique and versatile component of the synthesizer. One of its intriguing features is its ability to function as an oscillator when the “Response” knob is set to a high level, thus turning the filter into a soundsource.

In the EMS Putney, the Filter is essentially a resonant low-pass filter with a distinctive personality. It’s  a “treatment” because it can be used to shape and manipulate incoming audio signals.

When the “Response” knob is turned up to a high level, it introduces positive feedback into the filter circuit. This feedback, in conjunction with the filter’s resonance control, can cause the Treatment to self-oscillate.

When the Treatment self-oscillates, it produces a sine wave that can be tuned by adjusting the frequency control associated with the Treatment.

The pitch of this sine wave can be controlled using the keyboard, the built-in low-frequency oscillator (LFO), or by patching control voltages from other sources.

This unique capability allows the EMS Putney filter to function not only as a traditional subtractive treatment device but also as an additional audio source, expanding its sonic possibilities.

The ability to turn the filter into an oscillator adds an interesting dimension to the EMS Putney’s sound palette. It can be used for creating drones, sub-bass tones, and additional harmonic content, making it a valuable tool for sound designers and electronic musicians seeking to explore unorthodox sonic territories. The EMS Putney’s Treatment-as-an-oscillator feature is just one of the many quirks that have contributed to its enduring popularity in the world of electronic music.

Experiment with Signal Routing:

The beauty of the EMS Putney is in its flexibility. Experiment with different signal paths to create unique sounds. You can patch and repatch in various ways to explore new sonic possibilities.

Recording and Monitoring:

Connect the output of the Output Mixer to your recording or monitoring equipment to hear and capture your sound.

Document Your Patches:

Since the EMS Putney’s interface relies on patch cables and there are countless ways to route the signal, it’s a good practice to document your patches. You can use a pen and paper or digital tools to draw diagrams of your patch configurations for future reference.

Experiment and Be Creative:

The EMS Putney encourages experimentation. Don’t be afraid to explore different patching configurations and settings to discover new and innovative sounds.

Making patches on the EMS Putney can be a highly creative and rewarding process. It allows for a wide range of sound design possibilities and is a key reason why the instrument has been cherished by electronic musicians for decades.