21 March 2023

How does it work ?

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What is the Zef ?

The Zef offers the sound and the feel of a classical violin, with the virtually unlimited possibilities of amplification and analog or digital effects.

It looks stunning, is very convenient to use and is made entirely in France by its designers.

But the Zef is more than this: It is YOUR electrical violin, with a whole bunch of options to customize it and fine-tune it electronically and manually to help you reach YOUR sound ideal. And there will be more extras in the pipeline.

Unplugged, the Zef is a great silent violin for study, offering better sound, better response and better playability than a classical violin with a practice mute, or a conventional electric violin.

How is this possible?

When we created the Zef, we rejected the idea of having a solid-body (that is, a non-resonant body, the basis of nearly all other electric violins on the market today). For the forty or so years of its existence, the solid-body electric violin hasn’t really won over the vast majority of music-lovers, let alone violinists, with its sound or feel. There is nothing you can do about it: the raw vibration of a bowed string results in a sound which is perceived as artificial and unpleasant. A solid and inert body won’t ever communicate the same sensations to the violinist as a resonant body. Various types of electronic post-processing of the solid-body sound – common on better instruments, offer only slight cosmetic improvements.

We felt the electric violin needed to have its hollow body back, because it is this feature which filters the sound spectrum of the bowed string and gives the violin the sound we know and appreciate. But up to now a hollow body has always resulted in feedback problems at high volumes or when run through effects, making the amplified instrument unusable.


Well, no. Because what causes those problems is the body’s resonance, not its vibrations. The Zef represents the simple and elegant solution, to dissociate vibrations and resonance.

But how? 

The secret is in the holes! Without getting too technical (you can always ask us, we know our maths!), let’s try a comparison with the good old pasta sieve. Just like water, air is a fluid. As the water passes through the holes of the sieve, so sound waves, which are just compressions of air molecules, mostly go through the holes of the Zef – with the exception of very high frequencies, which are harmless as far as feedback is concerned. The problem of feedback happens not when the resonance body sounds, but when it resonates with the sound-waves coming back (hence feedback) from the speakers. This creates an over-resonance in the instrument which gets stuck on certain frequencies, creating the typical feedback howl. 

With the sound-waves incapable of making the Zef’s body vibrate, it is invisible, so to speak, to the sound from the speakers.

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So where does the sound come from?

Designed like a classical violin, with its arched top and back, proportions, f-holes, its sound transmission via bridge, sound-post and bass-bar, reproducing the graded thinning of the wood with diminishing hole diameters from the edges to the center, plus some compromises made with regard to the particular sound properties of aluminum, the Zef’s body vibrates in a way very similar to that of a classical violin. These vibrations are captured at two “hot spots”, on the Zef’s belly and back, by pick-ups using a piezo-electric polymer. PVDF, and transformed into an electrical signal, rendered by the speakers as a real violin sound – warm, lively, profound and nuanced.

Being able to genuinely interact with his instrument and bow, the musician can draw the whole palette of sound and modulations from his Zef, and not just variations in loudness.

Long story short: Amplified straight, the Zef offers the same possibilities as a classical violin, with the notable difference that the sound comes from the speaker – at 110dB, if need be.

We believe that the Zef is the perfect replacement for an amplified classical or electro-acoustic violin if your aim is a straight, amplified violin sound.

And it gets even more interesting if you play with effects – from the slightest reverb, via saturation, doubled octaves, to electro sounds or barbaric distortions. All effects have only the basic sound of the instrument to work on. If this sound is poor, cold, artificial and skimpy, so will the effects be. On the other hand… 

To get a nice fat, fleshy effect, full of flavor and nuance, the straight sound has to provide all this in the first place. To push the culinary comparison even further (we are French, after all 😉 ) You don’t make a Tournedos maître d’hôtel with beef from the supermarket at two Euros the kilo, and chemical sauce in tubes.

Plug in your Zef, you’ll quickly get the idea. But beware! It’s addictive!

Use of the preamp and settings

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The preamp makes some minor corrections to some overly present frequencies typical of bowed instruments in general, and even more so with the vibrational properties of the aluminum.

The majority of these corrections are hard-wired in the preamp. On the preamp you’ll find several settings.

1 The bass-cut 

The bass-cut permits to obtain three basic sounds, like the switch between the three pick-ups on an electric guitar.

A sound with balanced bass (white light on), for a natural acoustic sound.

A sound with boosted bass (red light on) like a jazz guitar or to boost a distortion (like the rhythm guitar in Rock / Metal)

A sound with deep bass-cut (yellow light on), like the bridge pick-up of an electric guitar. This gives a very acid sound with distortion, a bit like the solo guitar from AC/DC.

To toggle the bass-boost, just use the foot-switch on the left. The right foot-switch will change from red (boost) to yellow (acid) and from yellow to red.

To set the bass boost, the upper left button will work in « white » (natural) mode, the upper right in « yellow » (acid) mode.

In red mode (boost), no need to set anything.

2 The mid-range cut

Wolf notes on bowed instruments are typically found at the first position of the second highest string (A, on the violin). It is naturally too strong on the Zef (that’s why it is diminished by the preamp), but it does reproduce the real sound of a classical instrument, a feature all other electric violins lack. You can set the amount of decrease with the upper middle button.

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3 Volume

The central button of the preamp sets the output level of the preamp. It does NOT set the gain at the entry of the preamp!

To set it, turn it to between noon and 3 o’clock, then set the volume on your amplification system (electro-acoustic amp, console…) to a comfortable amount. You can now fine-tune your volume on the preamp.

The volume button on the Zef pre-amp may receive a Dunlop brand rubber extension, to be set with the foot.

As your hands are usually busy playing the Zef, this might come in quite handy…

Together with a distortion pedal, the volume may serve as an effect as it sets the amount of saturation. Just check how the guitar-heroes do it, and do not hesitate to copy them!

Cabling / setup

Cabling is rather easy. The Zef has to be plugged into its preamp, then into the effect(s) and finally into a mixing table or an amp. Of course, if the venue features it, you can plug directly from the effects (or the preamp if playing without effects) into the D.I. box.

Amp or mixing table ?

The Zef’s sound is already close to that of an acoustic instrument. What little treatment it needs is provided by the preamp.

That way, in the same way an electric guitar amp will correct some defects inherent to the instrument, the Zef’s preamp provides the final small corrections before the sound engineer or musician can color the sound on an amp or a mixing table.

But as said beforehand, most amps carry out corrections and alterations on the entering signal. So, whether you use an acoustic amp or an electric guitar amp, the Zef’s sound will inevitably be altered, where no alteration is necessary, or beneficial. The best sound we got out of the Zef was with monitors. These speakers are made for studio mixes and offer the most neutral sound possible. That’s all you’ll ever need with the Zef!

There are several portable monitors on the market offering more than enough power. 

To get the best out of your Zef, get a little two-way mixing table and connect it to a monitor. The result will be better than with an expensive amp, and cheaper.

That being said, feel free to try out several different amps which will color the Zef in different ways. In any case, you won’t need to hump your amp everywhere to be sure of a decent sound with the Zef.

Recommendations for effects

All existing electric guitar effects are worth testing, plus bass effects if you are playing a Zefoloncello.

If you are a newbie when it comes to effects, we strongly recommend a digital multi-effect, which is a cheap and satisfying way to try out a multitude of effects to find out what you really like and want.

Afterwards, consider buying separate effect pedals, analog or digital.

Different brands have different specificities:

Mooer build very small pedals for really affordable prices. They might give you a bit of noise, but they remain pretty interesting for effects you use only occasionally.

You’ll find very psychedelic effects with a little vintage feel to them at Electro Harmonix.

Boss is a well-known producer of multi-effects, loopers and standard pedals, like the Metal Zone.

At the high end, TC Electronics are reputed for their very neat and elaborate sounds.

Finally, do not hesitate to try out less well known or hand-crafted pedals, as you might find good surprises there.

To do so, we strongly recommend you to follow Facebook groups that deal in second hand pedals. These groups give you the opportunity to learn something about the pedals before buying them, and to resell them if ever they do not satisfy you. As a general rule, try to check out one or two Facebook videos about the pedal you consider buying.

With the Zef, some special rules apply:

Vintage wah-wahs for electric guitars like the Cry Baby or the Vox should not be used if you are plugged directly into a mixing table. Those pedals add a significant gain of about 18 dB to the signal (originally to saturate the guitar amp), and will thoroughly saturate a mixing table input. Moreover, violins or even viola have a higher treble range than guitars, and thus require wah-wahs reaching higher into the treble.

So we recommend you look out for a wah-wah with adjustable gain and / or volume, like the Morley, or other wah-wahs with a maximum of manual adjustments.

Finally, adding up wah-wah and distortion might lead to feedback in the treble, if you play it really loud. If you consider playing with this kind of effect, you should get a gate, for example the Boss NS-1. It is affordable and offers a wealth of possibilities to set it up.

This is the only configuration in which you might get feedback from your Zef. But in this configuration, you’ll also get feedback from solid-body electric violins, or from electric guitars.

In any case, distortion might generate so much noise that you should use a gate. Guitar players use them, and they are also recommended for use with solid-bodies.

Advantages of analog vs digital effects ?

Analog effects are reputed for offering better sound quality, but in the end it all comes down to taste and fashion. For sure, digital effects offer far more possibilities when it comes to pitches or octave doubling, or temporal effects like delay or reverb.

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Physical and acoustical operation, the musician’s view-point (Aurélien, viola player emeritus)

The Zef was conceived from the desire to play an electric violin that could offer a sound that resembles as closely as possible that of a classical violin. This sound offers incomparable richness of timbre and sound color. 

Talking about my personal experience, I’ve heard guitar players rage when they heard me playing my Zef viola, saying that playing with a bow, I had much larger sound possibilities than they had. It’s the bow which allows us to play so intricately with the sound parameters – if the instrument we are playing permits it!

Based on the general experience and dissatisfaction of solid-body players around us, we found that it was essential to pick up the sound from the body, and not just at the strings.

But fitting an instrument’s resonant body with contact transducers (piezo or other), makes it extremely susceptible to feedback.

So to stop the resonant body from triggering feedback, it had to be perforated with thousands of little holes, as close one to another as possible.

These perforations would render a wooden resonance body very fragile and would be too costly to pierce into some composite fiber material.

That’s why we chose aluminum – which comes with its own wealth of difficulties, which are dealt with by the preamp.

The pick-ups

The Zef’s pick-ups are piezo-electric polymers (PVDF, or PolyVinyliDene Fluoride), stuck to hot spots on the belly and back of the Zef. 




If you clean your Zef with a soft, dry cloth (as a classical violin in fact), just wipe softly over the pick-ups, without pressure.