2010... BUILT UNDER LICENSE FROM E.M.S. (Cornwall)
The Synthi HI-FLI Re-Release
I am pleased to say I have negotiated with Robin Wood at E.M.S. to re-release the HiFLi under License. The price for each HiFLi unit (including pedals) will be £2000 + shipping. This price is a reflection of the many hours of build time each unit takes (this is not a glorified 'stomp box' and is closer in complexity to a Synthi A or a VCS3 than it is to any stompbox. Dont forget the original HiFLi sold for £350 in the early 1970's which conservatively translates to about £3500 today!.)
I have now stopped taking orders for Hi-FLi units having
almost 50 people on the build list (15 on the official
list and 35 on the supplementary list for units which will
be built subject to agreement by E.M.S. )
current production levels it will take at least 4-5 years
to get through these orders! I may at some future time
open up the list again.
Special Thanks goes to Vincent Gallo, whose suggestions and interest in reproducing the Hi-FLi were instrumental to the re-release project.
last update: 11/5/2013
Here is a photo of HiFli's serial 03-05 completed. Note the pedal units now use 'SolaSound'/'ColourSound' 'shells' from Steve Macari's in London. These were also used on the 1970's units after EMS ditched the rather cumbersome big/heavy pedal units shipped with early models.
Designed by legendary EMS electronics genius David Cockerell
(of Synthi AKS/VCS3/Synthi100 fame) in 1972/3 probably primarily
as a guitar effects unit (though it certainly has uses as an
analogue effects for synth sounds) and used by the likes of
David Gilmour (Pink Floyd) and Steve Hackett (ex Genesis) and
others. I was intrigued by the air of mystique surrounding this
unit. It seems to be regarded by many guitar player out there as
the ‘Holy Grail’ of vintage analogue guitar effects.
Whether this is because it’s also one of the rarest effects in the world, maybe in part explains this. Although guitar playing is not something I am good at ..I was also intrigued by its possible uses on synth type sounds. The re-release is an exact duplicate of the circuits of the original mk2 HiFLi..down to using the same obsolete transistors and the same opamps. The only 'electronics' difference is my use of a very stable toroidal transformer based internal power supply.
The case design is of course different. The original was in a wonderful white fiberglass (very 1970’s style!) console..something that is beyond my skills to easily reproduce. Therefore I opted for a powder coated black steel chassis with iroko end-cheeks and a cnc engraved and machined top panel (I made this myself with my CNC engraver/router) in satin anodized silver aluminium. Part of the project was also to clone the original pedal unit..this being a crucial part of the HiFLi in my opinion.
The audio input (eg guitar or synth) is via a jackplug built into the side of the left pedal. Control voltages and amplified audio go to the main unit via an 8 way umbilical cable with Jones plug on the end (just like the original). The right hand pedal has a convenient pot to control the amount of preamp gain. This scaling pot was part of the original Moog pedal so I made good use of it!
HiFLi Main Features
The HiFLI consist of several sections. Those on the left half
are Top Boost, Octave Shift (containing Sub-Octave and Ring
Modulation features) and Sustain Fuzz. Then a Bypass Mixer
(mixing wet/dry signals) divides the left and right parts and
the right half consists of probably the most important part as
regards sound shaping, a wonderful multi-feature Phase Filter. I
also added 2 features that appeared on the original HiFLI mk2
units: a bypass front panel slide switch to bypass the left hand
side effects completely and send the audio signal directly into
the Phase Filter (very useful!) and an additional ‘Growl’ switch
that drops down the fundamental note extracted from the audio in
by 2 and 3 octaves (The Sub-Octave drops it by 1 octave). These
sub-harmonics are not just combined with the original sound but
used to modulate the phase filter thus allowing very
strange/bizzare new sounds to be created. The pedal unit is a
fantastic idea. All the front panels sliders simply provide a
control voltage to operate each effect..yes all the effects are
voltage controlled! On the bottom of each slider is a 3 way
slide switch marked ‘+,0.-‘. In the ‘0’ position the pedal has
no affect on that effect as you operate it and the slider acts
as the effect control. In the + or - position operating the left
or right pedal sends a control voltage that swings from +12v to
-12v or -12v to +12v as you move the pedal up/down. The
left/right pedals control the left/right hand effects when
viewing the top panel. Since there is an independent pedal slide
switch on every effect..you can imagine the creative
possibilities here! There are many many different sounds you can
create simply by altering the state of each pedal voltage slider
switch. This is a really great idea and is why I said earlier
that the pedals unit in my opinion is crucial to getting the
most out of the HiFLi.
Before we get on to the effects, an important function of the
HiFLi is to detect an attack/decay time from the input audio. So
for a plucked guitar string the initial attack and the point at
which the amplitude drops below a certain level is detected. The
attack detection is used to trigger other effects which I’ll
discuss later. An exponentially decaying envelope is also
generated from this attack/decay section. The attack/decay
extraction is rather sensitive and its ‘correct function’ (ie
single rather than multiple triggers as each string is plucked)
depends on how you play (solo/strum) and the input level of the
audio from the preamp. Thus there is a panel slide switch for
flipping between sensitivities..one for ‘solo’ and the other for
‘strum’ guitar playing. In practice I found you can play as you
wish in each mode and you get different responses/sounds..!
Audio in from the preamp in the pedal unit is fed to the Top Boost that is basically a treble boost. Makes quite a big change to the sound when you push the slider up ..particularly on fuzz sustain.
Octave Shift/Ring Modulation
This section involves a suboctave generator that extracts a
fundamental note form the audio in and drops it by one octave.
Rather than simply mix this suboctave with the original signal
something more sophisticated is done. A ‘pseudo’ ring modulation
effect occurs where instead of multiplying 2 waveforms, the
RingMod just adds a half wave rectified version of the
fundamental to the output of the Top Boost and thus can produce
a fundamental that is double in frequency..so a bit like what
happens with a standard RingMod where the frequency of eg a sine
wave sent in is doubled though waveform multiplication.
But in the HiFLi RingMod version one doesn't hear the typical metallic/bell like sounds. Rather this pseudo ringmod signal is sent to a pair of FET’s which act as modulators..modulated by the suboctave signal. The result is some great deep suboctaves the amount of which are controlled by the ringmod and suboctave levels.
A fairly standard but nice sounding fuzz section that can be
mixed with the output of the Octave Shift. The fuzz input is the
from the Top Boost section. The fuzz attack time is controlled
from the attack/decay section and is variable. On fast rise
times..the fuzz appear instantly a string is plucked. Slower
rise times allow the fuzz to ‘swell’ in amplitude after the
string is plucked. So you get a slewed fuzz effect. Great!
Here is where the major soundscaping effects occur. The phase filter is in fact 6 filters and FET/bipolar transistor switches that alter the signal path through the filters of audio fed from the left hand effects. The 6 different ‘Treatments’(selected by front panel rotary switch) are Vibrato, Phasing 1,Phasing2, Waa, Waw and Meow are the result of different paths the audio is fed through the filter sections. For any given phase filter configuration above, there is in addition, 6 different modulations you can apply to vary the frequency of the phase filter. Varying the frequency alters the amount of phase shift that occurs in the audio signal. These modulations take the form of ‘transients’ ie waveforms that are produced only between the attack and decay sections of eg a plucked guitar string. Outside of this ‘attack/decay’ envelope the modulation waveform goes back to a simple sine wave. The 6 transients are slow sine, fast sine, increasing amplitude sine, decreasing amplitude sine, ramp up and ramp down. Modulation speed is controlled via slider (or pedals) and modulation amount by another slider. Here is a great feature. The time taken for transients to appear modulating the phase filter is controllable. So there is a slew option ..controllable via the modulation ramp time slider/pedal. Finally there is a slider/pedal that directly shifts the frequency of the phase filter. This allows you to ‘sweep’ the audible range of the filter if you use pedal control.
The ‘Growl’ switch
option drops the fundamental by 2 or 3 octaves depending on the
switch position. As mentioned above, these sub-harmonoics are
used to modulate the phase filter not simply mixed with the
orighinal sound. This gives amazing/bizzare new modulations! The
amount of growl is controllable via the depth slider and also if
the increasing/decreasing sine modulation is selected, by the
decaying envelope extracted from the attack/decay section of the
My impression of the phase filter is that its the ‘guts’ of the HiFLI and produces an astonishing range of phasing effects form subtle vibrato to screeching wah sounds all with transient modulations on top! The Envelope and Fuzz bypass switch allows you to bypass completely the left hand effects section of the HiFLi and send audio directly into the Phase Filter. This was something (along with Growl) that EMS seem to have added in the mk2 version of the HiFLI..so you wont see it on earlier mk1 versions. Its a simple idea but allows for yet more different sounds..’clean phasing’ if you wish Finally the bypass mix slider is a simple dry/wet mix control of the audio output.
I would also suggest checking out the superb original HiFLi
demos by David
Mohr on youtube. All the effected sounds he makes I can
recognize and reproduce on the re-release HiFLi. I wish I could
play guitar as well as he does...thats not something I can so
easily reproduce :0) ! Note however David demos only a selection
of Hi-FLi sounds..there are many many more if you dig deep...
A/B Guitar demos of the re-release HiFLi vs 1972 mk1 original HiFLi
Here are some direct A/B sound comparisons of the new re-release HiFLi compared to a 1972 mk1 original, kindly loaned by Robin Wood at EMS.
Rather than my ropey guitar playing (as you can hear later!) I have used free public domain clean guitar samples to do the test. This is more scientific in that the exact same sample is played through both unit
THESE ARE CERTAINLY NOT THE BEST SAMPLES TO DEMO THE INCREDIBLE SOUNDS OF THE HIFLI. RATHER THEY ARE SIMPLY BEING USED AS A 'SCIENTIFIC' A/B TEST COMPARING ORIGINAL AND RE-RELEASE HIFLI.
Note: The original 1970's mk1 has no growl switch (that came in later versions) and so no A/B comparison was done with the growl switch settings in my test. Also the original unit loaned to me has a non-standard bypass switch (not the same as the one that appeared in later EMS units and which I have implemented in the re-release version ) so again no A/B test was done in bypass mode.
Phase Filter Treatments : Vibrato, Phasing 1, Phasing 2, Waa, Waw, Meow
Small amount of reverb added.
Note the modulation depth of the phase filter in the demos below is quite subtle. The HiFLi is easily capable of mad and very deep modulations! Its just I choose these as they seemed appropriate for the demos.
Original vs Re-Release Comparisons
Maybe a unique sound effect of the HiFli is the delayed fuzz
'swell'. A front panel potentiometer controls the fuzz 'attack
time' after a string is plucked. The amount of fuzz depends on
the loudness of the playing. The effect has been described by
Steve Hackett (ex Genesis) as a kind of 'backward' guitar..he
used this effect for example on the excellent Genesis track
'Ripples' about half-way through the song. It takes some
mastering to get the right strength of pluck and timing and the
preamp level setting in the pedal unit is crucial to get the
volume envelope to do its job.
Here is an A/B demo I made with some reverb added. Sounds
almost like a bowed acoustic instrument !
Boost: 0; Sub Octave 0; Ring Mod 0; Fuzz Level 10; Fall Time
slow; Rise Time '7 O'Clock position' ; Bypass Mixer 0; Control
Mod:N/A; Speed N/A; Ramp Time 0; Mod. Depth 0; Phase Filter
Tratment Phasing 2; Direct Shift 5. Some reverb added.
I think the tests show that he re-release is a very close match to the orginal. Any variations are likely due to my inconsistent playing in switching from one unit to the other and to precise fader settings on each unit.
Small differences in fader settings can make quite noticable sound differences especially the Phase Filter direct frequency shift fader.
The new release HiFLi uses professional 100mm long faders. The original uses 60mm faders and precise setting isnt easy using these and the faders are also not the best quality (cheap plastic type !) unlike the solid metal bodied faders used in the re-release version)
Further samples of the new HiFLi
Just some random effects..these only touch the surface of what the HiFLi can achieve!
Apologies for my iffy guitar playing ;0)
More extreme Samples with fuzz and growl (using guitar)
Fuzz + swept filter
fuzz_sweep1.mp3 fuzz_sweep2.mp3 fuzz_sweep3.mp3
Fuzz + Growl
Clean guitar + Growl
VCS3 Processed by the new HiFLi
Here are some quick attempts at processing a VCS3 generated sequence through the new HiFLi.
In all cases I deliberately used the same very simple
repetitive sequence generated using my TKS sequencer using osc1
and osc 2 through the unmodulated filter on the VCS3 in order to
focus on the HiFLi effects. All the various sound changes you
hear (filter sweeps, etc ) in the demos are generated purely by
playing with knobs and sliders of the HiFLi only.
NO knob twiddling at all on the VCS3. A little bit of echo to
add ambience is the only other effect.
the HiFLi and only process through the Phase Filter section.
proc1.mp3 proc2.mp3 proc3.mp3 proc4.mp3
Next I now include the front section (top boost/suboctave/growl/ringmod/fuzz) again just
playing with sliders:-
proc5.mp3 proc6.mp3 proc7.mp3 proc8.mp3 proc9.mp3 proc10.mp3
VCS3 Drone note processing
2 oscillator drone note from VCS3 constantly repeated by a TKS fed into VCS3 filter.
Processed sound through the HiFLi. Left hand effects bypassed as well as envelope follower.
Filtered through Meow Phase filter. Dynamics produce by slow sine modulation of filter + right pedal control of direct phase shift. Also some knob twiddling on the VCS3 to add further dynamics.