20 June 2013

Pedal Effects: MI Audio Neo Fuzz - Test and demo


Note: this entry was already published in my old Spanish version of this blog, around August / 2011. Just revisiting it here.
The Fuzz was the very first pedal effect I had and, I had it just because I've built one myself. This is an effect that accompanies me from the very beginning and therefore, it's very familiar and useful for me.
But, I was so stupid that I thrown to the trashcan my hand-made fuzz (among with another hand-made distortion unit I've also built that time). With the past of time, when I wanted to recover the sound of such a fuzz, none of the multi-effect emulations (Zoom GFX-8, POD X3 Live, etc) and none of the several fuzz pedals I've tried leaved me satisfied.

The closer I went to that sound was with the Hudson Electronics' Stroll On, an expensive clone of the Tone Bender MKII but, cheaper than the D*A*M one and, with a reasonable lead time.

But anyway, the fuzz is a cursed effect. It can sound really good or really ugly, depending on several variables. Fuzz magic depends on a correct election of its set of transistors and a correct biasing of such a set.

In my case, I more interested in Germanium fuzzes and, unfortunately, production of germanium transistors is really inconsistent and, there is some uncontrollable rawness in each one. Just that unpredictable factor is what produces a more musical result (respect of silicon ones), in a similar way as tubes sound more musical than the more technically perfect transistors.

One more turn to the screw, germanium transistors are very sensible to temperature changes and, in extreme conditions can stop to conduct the signal. This obliges you to have to re-bias transistors to bring back the nice sound to the unit.

Another typical issue is related to the interaction between this pedal with every different rig (guitar, pickups, cables, amp and rest of pedals). Early pedals were originally designed for electronic organs and, therefore, the input impedance was established according such a kind of instruments and, that means that is actually very low compared to the needs of an electrical guitar. By example, the Fuzz Face had an input impedance of 1 KOhm, when your amp has an input impedance of 1 MOhm (1000 times higher).

A fuzz works better when it's receiving the direct signal from your guitar, because under such conditions, pickup overload is creating the right sound.
Typically, if you place a modern pedal, with a very low output impedance (below the 1 KOhm that expects the fuzz), the sound of the fuzz will be compromised.
Additionally to all that, depending on the pickup we use (single coil, humbucker, low / medium / high output...) the fuzz sound can radically change.

All these issues, typical in germanium fuzzes, drove me to search for some current alternative, with special interest in to find some fuzz with a certain control of tone and bias and, that can be compatible with the rest of the pedalboard.

And, this quest lead me to the MI Audio Neo Fuzz, which sound liked me in Youtube videos and, which technical specifications seemed to cover all my requisites.

So, in this entry, I will talk about my impressions while testing this interesting and modern unit.


It comes in an anonymous cardboard box, without any kind of logo. Just a simple stick on the upper side identifies the product.
Inside, the pedal comes wrapped in an air-bubble plastic sheet and, you can find a paper sheet with the description of this product and the basic function of its knobs and switches.
There are no example settings but, just some few notes about the function of each knob or switch, to understand how each change contributes to the overall sound.

Most of pedal makers forget to include some example settings that can be of help to get the basics of its pedals, something very interesting when you face any new effect for the very first time.

A second sticker says that this product has a warranty of 5 years!. That talks about the quality that should have such a pedal.

When you open the back cover, you can see a couple of PCB containing the components and, they look really professionally finished (bright soldering, rigid wires, etc...).

The unit is slightly wider than any typical pedal (MXR, Ibanez, Boss, etc), closer to the size of Voodoo Lab pedals.


According to the maker, this fuzz load 3 military NOS germanium transistors, around 30 years old, that were carefully selected (he thrown around 70% of bought transistors).
It seems that this fuzz isn't a clone of a vintage design but, it was designed from scratch, based in a careful analysis of several classic fuzzes, taking into account the issues related to each particular design and, checking how each component contributed to the tone.

Always according to the maker, it seems that his design has a double negative feedback that helps to stabilize the variable behavior of germanium transistors, even with sudden temperature changes.

This pedal works as any effect based on germanium transistors, that is, with the positive grounded. It allows to use an external supply unit, with a typical boss barrel connector with negative center (the standard in pedals, what is nice!). The unit will swap negative and positive internally.

Even that this is a genial idea, you should take into account that you could do that only in the case that you have some power supply with ISOLATED outputs or, if you use a separated power unit just to feed this pedal (among any other with germanium transistors or reversed polarity).
Watch out, you can damage your pedal and / or your supply unit !!!.

I am running it with a Voodoo Lab Pedal Power 2 Plus supply unit, which has isolated outputs so, I have no issues.

Anyway, worn low efficiency batteries are the typical way with fuzzes. That way, they sound the best.

All these characteristics, together with the versatility of its controls and, the fact that this design was made from scratch, with a moderner take but trying to preserve the "vintage tone", is what made me to try once more with another fuzz pedal.



One of the two bigger knobs of this unit. As in any fuzz, it controls the output level of this pedal.


The second big knob. It controls the amount of the fuzz effect applied to the original signal and, it's highly dependent on the rest of controls and, very specially, on Bias and Load settings.

This is control that you don't see externally in fuzzes. If any, they are small trim pots inside the unit that force you to open the back cover, tweak, test, tweak, test.
The Bias controls the sweet spot of its transistors, where they can work more linearly and, where you achieve the best headroom to handle negative and positive signals.
As I mentioned before, this is one of the key characteristics I was looking for, to allow me to comfortably re-bias transistors when needed.

I don't know of any other fuzz having this characteristic.
Load changes the input impedance level, in a way that the pickup sees different load levels. This allows you to adjust the load to different pickups and, to compatibilize this pedal with the rest of your pedalboard.
One more specific characteristic that made me to choose this fuzz.


Most of fuzzes have a tone control that just cuts the highs, throwing them to ground. The Neo Fuzz increases the low end when rolling on to left hand or, increases high end when rolled on to right hand.


One more unusual control in fuzzes. This knob controls the content in Mid frequencies of the sound.
To left hand, it seems to enhance mid-lows while, to right hand it seems to enhance mid-highs.
This control is highly dependent on the Tone knob. If Tone is all they way to left hand, Body hasn't effect.
Tame Switch

This 3-positions switch is the responsible of controlling the higher frequencies content.
In the middle position (off), nothing is being cut and, therefore, you get the brightess (or piercing) sound.
To the left (some), some is being cut, helping to tame the sound of bright guitars or amps.
To the left (lots), the high end is being drastically cut and, it's specially good for bright hi-gain amps.
This control is also highly dependent on the Tone control.


I've tested the fuzz alone, to check what can it do by itself and, to be sure I am getting the best fuzz tones.

Differently to other fuzzes, which they have some spot where they start to sound over-compressed and over-saturated, with excesive hard clipping, the Neo Fuzz was delivering a very dynamic sound, covering all gain levels (from a colored booster to a powerful fuzz) with spades.

Once the Bias was set up, the Load knob allows you to control the body of the effect, so we can achieve very different level of compression in the effect.

The four tone controls help you to achieve barely any kind of fuzz sound you have in mind, from dark and deep tones to bright and cutting trebles.

In some setting, I was achieving a sound very close to an Octavia effect (for a casual!).

Indeed, this is a very versatile fuzz, in the line of the Z.Vex Fuzz Factory but, with an important difference.
While the Fuzz Factory seems to be oriented to achieve "Freaky" effects (apart of the basis tone, that's excellent), the Neo fuzz seems to be oriented to achieve only useful variate sounds, without covering the extremes of the Fuzz Factory.


Following video covers my experience while testing this pedal, in all the combinations that I was able to imagine.
It starts describing the characteristics of the unit, functions of each control and, continues with the step of finding the right Bias spot.
Once the Bias was set up, we check the Load knob and see how the body and overall sound changes.
Then, we go to analyze the several tone controls, seen extreme and middle combinations.
Once all controls were seen, there is a small series of riffs with different random settings, to check more clearly the different voices of this fuzz unit.
I am finishing the video checking the ability to clean the signal when rolling off guitar's volume.

As an additional note, I have to say that changes in tone are more notable in real world. It seems that recording and further audio transformations removed some of the sound nuances and, very specially in the high end zone.

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