EMS Synthi HiFli

An amazingly-rare EMS Synthi HiFli with original chrome stand and early heavy-duty twin pedals.

This is a knob-twiddler's dream of an effect: your guitar will never sound the same again.

Number one in Analogman Tom's list of rare guitar effects from his excellent book.

Used by David Gilmour - see gilmourish.com for further details - he bought a prototype in 1972 and from what he recalls it was “very, very expensive”; it was used during the recording of Dark Side Of The Moon

The Hi Fli was designed by David Cockerell in 1971 for EMS. Only 350 were originally made making it a very rare beast indeed.

This rare early unit EMS Synthi Hi-Fli comes with its original chrome stand. Serial number 9064, the sixty-fourth Hi-Fli made, it is in beautiful condition and features the early series chunky nylon-dipped pedals. It features the excellent Envelope Bypass mod on a small chrome toggle switch which makes it useable with less percussive sound sources. A mains on-off switch has also been added on the front panel. It was retrofitted with the Growl modification by EMS.

The Hi Fli was actually referred to as a synthesizer in the original ad, but it’s basically an analog multi effect processor, which can be used on vocals, guitars and organs. It has two footpedals, which could be routed as control voltages/expression pedal to any of the slider functions. It’s got no memory to bank up settings, – everything is in real time, so one had to manually tweak the sliders for each tone change. You'll suddenly hit upon an amazing combination while tweaking the knobs - be sure to hit record as repeating it could prove tricky.

Top Boost: Provides up to 30 db treble boost.

Octave Shift: Drops the pitch by an octave.

Buzz Switch: Adds high frequencies overtones to the sub-octave signal.

Ring Mod: Produce an octave higher when a signle note is played and the typical ring modulation when two or more strings are played.

Decay Rate: A rotary control controls the decay time of the ring mod and octave shift signal level.

Sustain Fuzz: Special circuits detect the beginning and end of each note and apply upper harmonics.

Attack Rate: A rotary control varies the rise time of Sustained Fuzz signal. Notes can be sustained even though the original signal has dropped by more than 20db.

Pedal Switches: The switches under the sliders combine the pedal control with the manual sliders. Selections of switches with pre-set slider positions enable the pedal to change treatments instantly.

Solo/Strum: This switch alters the Hi-Fli’s sensitivity to signal attacks and should be set to more sensitive for single notes (i.e solo).

Bypass Mix Fader: This central slider controls the mix of the original and treated sound. In the high position only the input pre-amplifier is in-circuit. The bypass footswitch gives instant access to this position. The output from the Octave shitft, Ring Modulator and Fuzz Sustain sections are re-combined and go to the phase filter and modulator section.

Control Modulation Selector: 6 position control knob.

Treatment Selector: There are six distinct modes of operation – Vibrato, two modes of Phasing, normal WAA-WAA (1 resonant peak), WAW-WAW (six resonant peaks) a completely new sound, and finally MEOW (two sets of three resonant peaks moving in oppisite directions.

Modulation Speed: This slider operates in the first 4 positions of the control modulation selector, providing a fine frequency control.
Modulation Ramp Time: Operates in positions 3 to 6 of the conrol modulation selector.

Modulation Depth: Controls the depth of the Phaser.

Frequency shift: This controls the frequency domain in which the modulation waveform operates, being central for symmetrical modulation.

L.E.D selectors: Two light emitting diodes show the movement of the modulation waveform.

Please also see: ems-synthi.demon.co.uk,

“AnalogMan’s Guide to Vintage Effects” by Tom Hughes

and the David Gilmour Gear Forum.

Excerpts from the Gilmourish post written by HiFli owner “Richard”.