Eventide Instant Flanger (1976–1979)
The Eventide Instant Flanger is a rackmount flanger built from 1976 until 1979. It originally sold for $579.50. It was a stage version of Eventide's earlier FL201 studio unit, with the FL201's design modified and given a revised front panel. Inside is a 512-stage bucket-brigade delay line, with two independent delay lines and internal clocking that gives delay times from 10 to 50ms. The internal oscillator could run at frequencies up to 25 kHz, which makes scan rates of roughly 25,000:1.
The front panel has rotary controls for Bias, Depth, Rate, Feedback, Boost, Manual, and Mix. LF and HF indicators show the status of the internal oscillator. Both HF and LF inputs are present, along with a 1/4-inch jack output. The unit was aimed at electric guitar and bass players, though Eventide's own literature also pitched it for theatrical, TV, radio, and recording work. Jimmy Page used one.
Reception, then and now, has been consistently warm. Sound on Sound (September 2003, p.62), reviewing the Clockworks Legacy plug-in version, noted that the Instant Flanger has a refinement and subtlety that puts other flangers to shame. Owners describe the hardware unit as warm and organic with a sweet high end, great on drums, vocals, and guitars. They also call it noisy by modern standards, prone to running hot, and not a subtle effect. It is a collector's item today and hard to find in good working condition. A recent Reverb listing was around $2,000. Known maintenance issues include a noisy internal power supply and capacitors that may need replacing.
Documented specs are thin in places. The unit is 19-inch rackmount, 1U, and weighs 18 lb (21 lb shipping). Input impedance is 100kΩ, output 100Ω. THD is listed at 0.1%, signal-to-noise at 70dB, and dynamic range at 90dB. Power consumption is 6W. Sources conflict on bandwidth - one says 10 kHz, another 40 kHz - so that spec is left out here rather than guessed at.
Similar items on eBay
No exact Eventide Instant Flanger listings are live right now — these searches show current Eventide and similar vintage synth gear on eBay:
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.