EMS Synthi Hi-Fli c1973 (HiFli)

Rare early production EMS Synthi Hi-Fli, dating from c1973, in excellent condition following a full overhaul by EMS earlier this year; comes with twin footpedal unit - contact us now for more details.

Select Currency

You missed it!


Rare early production EMS Synthi Hi-Fli, dating from c1973, in excellent condition following a full overhaul by EMS earlier this year; comes with twin footpedal unit – contact us now for more details.

  • This is a knob-twiddler’s dream of an effect and the ultimate in hens’ teeth: 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 this Gilmourish blog for further details – he bought a prototype in 1972 and from what he recalls it was “very, very expensive”; Gilmourish suggest it was used during the recording of Dark Side Of The Moon

This unit comes with a dual footswitch unit and was serviced by EMS in April 2019. It is an early example dating from c1973.

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 Only 350 were originally made making it a very rare beast indeed.

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 can prove elusive.

See listing photos for a shot of David in his home studio in 1972 with a prototype of the Hi-Fli.

HiFli Controls:

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.

In my experience, there is one unit that stands above the rest: the EMS Synthi Hi-Fli. This is the ultimate vintage guitar pedal, whether for its features, sound, looks, size, scarcity, price, or simply its star quality. I’ve been fortunate to own four or five over the years, with some overlap between different variations. At one point, I had a rare early prototype and one of the last MkII units. They all sound different, and each one has its own unique character. This is due to the varying degrees by which the 40-year-old components in these complex, discrete circuits have aged. I could have justified keeping them all on the basis that each had unique qualities I enjoyed. But my keeper unit is one of the last produced by EMS. Built starting in 1972, the Hi-Fli was designed a year earlier by David Cockerell, who was also responsible for such legendary synths as the EMS VCS 3, Synthi AKS, and Synthi 100. In ’74, he moved to Electro-Harmonix, where he designed many classic pedals, including the Small Stone, Electric Mistress, 16 Second Digital Delay, and Microsynth. David Gilmour of Pink Floyd is the most renowned early adopter of the Hi-Fli. He began using a prototype onstage in 1972-’73 and in recording Dark Side of the Moon. A Hi-Fli is also visible in the film Pink Floyd: Live in Pompeii. He has two units to this day, though Floyd gear expert and Gilmour tech Phil Taylor maintains that he didn’t use the Hi-Fli extensively. The prototype was displayed at the stunning Pink Floyd: Their Mortal Remains exhibit at London’s Victoria and Albert Museum last year. Around 350 Hi-Flis were made, and other notable users include Steve Hackett of Genesis and Todd Rundgren.

Industrial designer Martin Holbrook’s iconic look for the Hi-Fli was a futuristic, curvaceous cream-colored fiberglass console, typical of late-’60s space-age design—although it was disparagingly referred to as “the toilet seat.” After the first 10 prototypes, which featured twin foot pedals built into the stand that supported it, the design was changed to a separate stand and pedals.

David Gilmour of Pink Floyd is the most renowned early adopter of the Hi-Fli. He began using a prototype onstage in 1972-’73 and in recording Dark Side of the Moon.

The prototype design, though undoubtedly far more aesthetically pleasing, was less successful ergonomically. Access to the pedals under the sizeable control section was difficult while playing guitar. After EMS ran out of cream fiberglass cases, the final 10 or so units produced by Robin Wood were housed in garish orange-painted wooden boxes.

While the early prototypes miss some of the later units’ improvements, and some mid-period Hi-Flis didn’t have the “growl” modification, all examples I’ve played have been utterly captivating. I know of no other effects unit that is as sonically versatile or as compelling and expressive. The Hi-Fli oozes inspiration, but if you find a sound you like, be certain to hit record quickly, because it can be difficult to precisely recreate settings. There are many variable parameters, and the slightest movement of each of nine faders has a significant impact on the sound. So, the Hi-Fli has all the flaws, foibles, and idiosyncrasies you’d expect in an analog synth from the early ’70s. It is one of those rare magical devices that surprises and delights one moment, only to obfuscate and exasperate the next.

Set the Controls for the Heart of the Sun
The Hi-Fli is complex and nuanced. Of course, you can just plug in and move sliders and switches until you get a sound you like. But the Hi-Fli is divided into two main sections by the bypass mixer, which controls the wet/dry mix. On the left are the top boost, octave shift, and sustain fuzz controls, and on the right are the controls for the stunning and multi-featured phase filter section. This is where you select and shape the various phaser, vibrato, and filter settings: vibrato, phasing 1, phasing 2, waw, wawa, and meow—tags that provide a tantalizing glimpse of what’s possible.

Three faces of the EMS Synthi Hi-Fli (from left to right): one of the 10 original prototypes with pedals directly beneath the unit; a final production model after EMS had run out of fiberglass housings, with the “growl” switch in the phase filter section and a bypass switch in the midsection; and a mid-period example without the growl mod. The middle unit is the author’s and can be heard in the sound clips online.

Running along the bottom are the switches to control the left and right foot pedals. Being able to select positive or negative voltage for the various sliders (or leave them off) for each pedal puts a vast array of control options at your disposal. On the top left is the solo/strum switch, which determines the attack/decay time sensitivity. Later units also feature the growl, which uses a subharmonic to modulate the phase filter, yielding even wilder sounds.

If I filled this entire magazine, I’d still fall short of conveying the depth, scale, and sheer craziness of the sounds the Hi-Fli can create. One minute you’re in the amphitheater at Pompeii making seagull noises; the next you’re like an axe-slinging Kraftwerk mannequin. Yet it also excels at gentle and subtle phasing and vibrato. This is a design of staggering quality and ambition with possibilities that stretch far beyond anything else created for use with an unmodified electric guitar in the ’70s. Like a guitar, the Hi-Fli will sound very different depending on who is playing it. Over the years, I’ve created all manner of scrumptious electronic noises using different Hi-Flis, and I still don’t feel I’ve come close to exhausting the sonic possibilities of this wondrous device. But in the neighborhood of $5,000 and up today, Hi-Flis are an investment in more than a learning curve.

Please also see:,

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

and the David Gilmour Gear Forum.


In excellent cosmetic condition with only minor scratches on the face. The case is very good with some dings and signs of wear. See photos for more information on cosmetic condition.

Voltage Information

220/240v unit. A step-up transformer will be required for use on 110/120v supplies. Please ask if you need advice on what to use. We do not recommend using cheap, generic Chinese mains transformers.


For sales in UK/EU, this item is on the margin scheme for second hand goods. VAT-free sales are not possible for this item.


Grabbed a Roland RE-201 (early edition killer pre-amp) and Roland DC-50. Absolutely STUNNING. These guys truly live up to the hype. They are meticulous in caring for the gear. Also, I have a few guitar pedal and plug-in emulations of tape-echo sounds and after plugging in the real unit I can't tell you how insane the difference is. It is incredible. Especially that tone from the early pre-amp! I am totally amazed. I am in heaven :) They made it safely to Nashville from the UK and were packed really really well! Thank you so much!! Worth every penny.

Chance Allen

“If not a new language, then at least a very challenging, old dialect that will take me some time to assimilate. I’ve been waiting a long time for the challenge. Thank you @soundgasltd, she’s a beaut...and nobody prepares and packs like you fine folks.”

Justin Meldal-Johnsen

Just wanted to say thank you so much for your pinch roller and echo tape. I've had a space echo for years, been sent to a shop in NYC and it never worked quite right. After installing the roller and tape, my echo works like a dream. Really incredible expertise you all have! Thank you.

Andrew Potter

"Finally, a company that tracks down all those brilliant curiosities that bring so much character and personality to a studio."

Matthew Herbert

“The Space Echo made its way to me - it looks and sounds beyond dreams, thanks guys for your great service and communication.”

Julius Bonson

Purchased a Juno-60 and it works beautifully. Having gotten one teched before, I knew it was worth paying a premium to get it future proofed and Soundgas does just that. Shipped professionally from the UK to USA. Appreciate their expertise and professional demeanor!

Eric Cullen

"Still in shock! Can not believe how good the seller is. This product was inspected, and shipped from the UK to the USA quicker than orders from my home state. Highly recommend these guys."

Thomas Tedesco

"Excellent equipment, wonderful service. I fully recommend Soundgas to anyone in the vintage gear market and I will definitely be a return customer. The gear itself was exactly as advertised and in great condition."

Hallam Kite

"When you are spending big money of vintage gear it's nice to have the confidence of impeccable service, sales and support... some of the best in the industry! Impeccable people, incredible equipment… my poor poor fiancé"

James DLR - Sofa Sound/Metalheadz

"Yes, sure, you can find a Space Echo on eBay, but you won’t find one like this — that’s certain. I am so pleased with my decision to buy from Soundgas, and suggest you stop your search now and just send them a message. You will undoubtedly find yourself writing an ecstatic review about yours in short time."

Ben Evolo

As good as it gets. Tony, Dec and team have been incredible, prompt communication, great advice and outstanding service. It really felt like my Polysix came from a loving home.

Ben Parm

"The packing job to get it over to the US was superb, and the sound and performance of my Space Echo exceeds all of my expectations. I hope to do business with Soundgas again in the future. Many thanks!”

Rhett Daily

“If you are a vintage audio gear head then this is the place you have been looking for all your life. Pretty much any piece of classic or obscure kit that you are after is available here... But the clincher for me is that the gear they sell has been restored by their top techs (unless otherwise noted) which is really very important when dealing with, for example, synths from 30 years ago.”

Lincoln Barrett / High Contrast

"Engaging with old gear can sometimes be filled with a lot of uncertainty, and I can't imagine what more could be done to reduce this aspect of it on top of the service you provide. Really phenomenal and I couldn't be happier."

Stephen Voinea

“I’ve bought a number of items from Soundgas recently, and have been really impressed with their service. It takes the stress out of buying vintage gear to know it’s been properly (and faithfully) serviced or restored. Their after-sales service has also been exemplary. Highly recommended.”

David Wrench

"808 is up and running. It’s hard to stop playing it. Like even to eat. Extending testing is quality control and the quality of your stuff combined with customer service is one of the reasons Soundgas is so successful in my opinion."

Brett R

“Imagine the perfect eBay.... with everything you never knew you wanted… and you can rest assured that your vintage and rare wobbly sound device will turn up on time and in one piece and possibly in even better condition that when it left the workshop. Soundgas - literally amazing."

Josh Lloyd-Watson & Tom McFarland - Jungle

"Soundgas has an unbelievable selection of the cool, old stuff that’s hard to find. Tony knows his stuff and goes out of his way to make sure the transaction is a smooth one. Thanks guys!"

Tucker Martine - Flora Recording

"Packed with love and care. A stampede couldn't have crushed this thing. Works great and sounds like a dream. I love you Soundgas."

Ben Van Vlissingen

"Soundgas offer a great service, sourcing esoteric gear that works great."

Tom Rowlands - Chemical Brothers

Fantastic. From initial contact to the product landing at my door the service provided was outstanding. Safe and secure shipping, quality serviced product.

Tom Johnston

I have been buying vintage stuff for a long time from resellers/stores/techs. I've never been so surprised and pleased after opening! Just received a Roland RE-201 and VX55 mixer, they look and sound amazing! Thanks to Tony/Declan for the service and the Soundgas team will be back!

Dong Yun Seok

"Soundgas provided the absolutely top service in terms of item quality as well as service and communication. Shipping was fast, packing was top notch. These people deserve the best reputation they already have. Many many thanks, guys."

Dupille Luc

“I purchased a completely overhauled vintage valve Binson Echorec 2 T7E modified with varispeed, wet-only output, and a new paint job from Soundgas in early 2018. Tony and his team did an amazing job during every step of the purchase”

Matt Morton

"DREAM. COME. TRUE. My music has taken me around the world a few times...and if you are like me and absolutely adore vintage gear...Soundgas is the stuff of LEGENDS. It's the shop that people like us search for our whole lives- fantastic and rare selections, and the technical know-how to repair and or mod these vintage items to get them into shape to flow with your modern setup."

Tom Gossin

"Just received my Roland RS 505 Paraphonic! Thanks so much - arrived very promptly, well packaged, in great condition and sounds amazing! Best seller."

Koko Hiras

“The perfect place to hear, learn about and then buy your most wanted piece of vintage music gear! I've not only managed to buy a rare piece of equipment I really wanted, but I have the guarantee it's been serviced, and I got it from people who are clearly passionate and knowledgeable about what they do, as well as super friendly and responsive by email. Thoroughly recommended!”

Colleen / Cécile Schott

“I have bought two Moog synths from Soundgas over the past year, and I cannot say enough wonderful things about their selection of vintage products, the level of service, diligent responses to email, and expedient shipping with copious protective packaging. Soundgas is an impressive operation. My synths also sound amazing! These folks have made my vintage keyboard dreams come true in short order!”

J Yates


The Weird and the Wonderful – An Auction Update

The Weird and the Wonderful – An Auction Update

We can't stop here, this is bat country! Our next auction (November 22nd) features some head-turning, show-stopping synths, however we also wanted to put the spotlight...

PUBLISHED: 21st Nov 2023

Teaching Machines Wellspring Reverb Review

Teaching Machines Wellspring Reverb Review

Tony takes a dive into the new Welsh-made Wellspring Stereo Reverb and comes up with a very big smile on his face.

PUBLISHED: 17th Oct 2023



We stand behind our gear with a guarantee of your satisfaction - see the FAQ section above for full details and buy with complete confidence.


When buying more than one item you only pay the shipping on the item with the highest shipping cost. Calculated automatically at checkout.


Get in touch via the contact page. We know & love our gear and we want to ensure you get something that matches your needs (that, and we just like talking gear).

Select your currency