Eventide Instant Phaser (1972–early 1980s)
The Eventide Instant Phaser was the first phaser that could be driven by an envelope follower, not just an LFO. That made it a studio workhorse in the early 1970s, a box that could respond to the dynamics of the music instead of sweeping at a fixed rate. The JE-1 variant was introduced in early 1972 and the design sold for nearly a decade. Studios and touring musicians both took to it right away, and it became a staple of studio engineers through the decade.
The phaser is a 4-stage design, with the stages tuned to 220Hz, 440Hz, 900Hz, and 1800Hz respectively. The effect comes from mixing the original input with the swept all-pass filter output. The speed control runs from 0.03Hz to 12Hz, which is about one sweep every 33 seconds up to 12 sweeps per second. The front panel has a speed knob, a rate indicator lamp, and a power switch, plus bypass, invert, and phase switches. Inputs and outputs are unbalanced 1/4" jacks. It runs on 117V AC, 50-60Hz, draws just 3 watts, and the rack-mount chassis measures 19" × 1.75" × 8.5".
According to the Effectrode history, the envelope following was what set it apart. At the time, every other phaser and flanger relied solely on LFOs. The envelope follower could be set for detection speed and sensitivity, so the phaser could sweep harder when you played harder. You can hear that sound on records like Jimi Hendrix's "Angel" and Little Feat's "Dixie Chicken."
The record is a bit fuzzy on model lineage. The Effectrode article describes an earlier PL-1 Instant Phaser as Eventide's first consumer product, with the JE-1 as the main subject of most documentation. Whether PL-1 came before JE-1 or was a variant isn't clearly established in the sources. The JE-1's frequency response is documented at 20Hz to 20kHz ±3dB, with THD of 0.02% at 1kHz.
The unit is built with discrete components, FETs and resistors, so it's repairable today. FET failure is a known issue, though, and it can kill the phaser entirely. EQ Magazine (February 2009, p.13) later included the Instant Phaser among fifteen of Eventide's best effects from the past thirty-five years, when the company bundled it into a software package of classic processors. No original price, production quantities, or collector market values are documented in the available record.
Known specs:
- 4-stage phaser, tuned at 220Hz, 440Hz, 900Hz, 1800Hz
- Speed: 0.03Hz to 12Hz
- Frequency response: 20Hz–20kHz ±3dB
- THD: 0.02% at 1kHz
- Inputs/outputs: unbalanced 1/4" jacks (2 in, 2 out)
- Power: 117V AC, 50-60Hz, 3 watts
- Dimensions: 19" × 1.75" × 8.5" (rack-mount)
- Envelope follower + LFO control
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