The Blues Pro, along with the Crunch Box, have been a couple of pedals that have gained a lot of fans over the years we have been making them. When I designed them long ago, I wanted to create a pair of pedals crammed with many different sounds, accessible via three knobs. The simplicity of the design grabbed the attention of a lot of musicians but as the years ticked on, and more and more overdrive pedals hit the market, we received feedback from the fans asking for a bit more from these designs.

This feedback saw the birth of the Super Crunch Box idea (that is still in prototype phase), and now the Super Blues Pro!

The Blues Pro has always delivered in the low/mid gain overdrive tones, and sounds great through any amp or guitar/pickup combination. As the gain goes up, you can get more compression and super-squishy fuzz tone at a flick of a toggle switch. The mid-focused TS sound is a classic found on a lot of blues and rock recordings, and the Blues Pro took that initial design a step further. That is how the Super Blues Pro was tackled – but what could I add to keep the pedal true to its origin, but extend it a bit further?

First, headroom! Like the new Boost ‘n’ Buff v.3 and soon, the Super Crunch Box, we have added internal voltage multiplying circuitry to boost the operating voltage from a 9V only input, to give the Super Blues Pro 18V supply. This added headroom gives more clarity in the top end and attack and really adds that sparkle for low-gain boosting your amplifier.

Next, I wanted to expand the kinds of overdrive tones that can be dialled in and stand alongside the tone of the original Blues Pro. This has been done with the introduction of the DETAIL, BODY and TRIM controls:

DETAIL – This is essentially like the original tone control on the Blues Pro

BODY – One of the main features of the Blues Pro is a bass/low-mid boost to help get rid of the typical mid-hump of the typical TS type of pedal. The BODY control essentially makes this variable, so you can go for a more mid-focused tone, traditional Blues Pro (with the BODY set to 12 O’clock), or even more low end by cranking the BODY

TRIM – This is essentially a second gain control, which affects the gain in a different part of the circuit. The TRIM and GAIN controls have different frequency responses, so you can achieve a wide variety of tones by adjusting these two controls. The standard Blues Pro sounds can be achieved with the TRIM control set to 2 0′clock.

Finally, I wanted to give users the control of the clipping structure of the overdrive signal – allowing anything from a low-gain, open overdrive tone to the super-compressed, mid-gain fuzz found in the previous version. This is controlled via the two toggle switches, each having three options; Silicon, MOSFET or none.

The interesting thing (which I don’t think has been done before,… I’m certainly not aware of any instances) is the ability to choose the clipping device for each side of the waveform individually. The top switch controls the clipping of the top of the waveform, while the bottom switch selects the clipping device for the bottom of the waveform. This means that you can now experiment with say, diode clipping on the top, and MOSFET on the bottom, or No clipping for the top of the waveform, but diode on the bottom etc.

Another thing to point out as well is that the silicon diodes for the top and bottom are in fact different diodes, to add a slight asymmetry to the waveform in Silicon mode. But this also means that you get a slight difference in the tone and feel of the pedal swap switch settings. Also, the MOSFET mode actually uses the clipping characteristics of the MOSFET itself, not the reverse protection diode commonly integrated into the devices.

The range of clipping tones available include the classic TS sounds of the original Blues Pro, or a range of compressed fuzz sounds, all with varying attack dependent on the diodes selected. As the gain increases and bringing in the TRIM control you can opt for a smooth, mid-rich overdrive a la Dumble amplifier tones, or an open, chiming top-end boost.

I’m really excited about the Super Blues Pro, and I’m really looking forward to getting it into the hands of the Blues Pro fans!

-M

In the discussion with Jon from Guitar Noize, I was asked about all of our new releases planned for 2012 (which there are many!!) and things that are in the pipeline. Have a listen on the link below and stay tuned to the podcast series for more featured Australian builders and musicians.

http://www.guitarnoize.com/the-guitar-noize-podcast-episode-1-mi-audios-michael-ibrahim/

-Mike

But as of late, there have been a lot of manufacturers using the PT2399 chip; a digital delay that emulates an analog or tape delay sound. The PT2399 is a great value bundle in one IC, however it does have its limitations and these are apparent if you have played the current pedals in the market. So instead of trying to force this chip to be the replacement for your Echoplex, I decided to embrace these limitations and release a delay pedal that doesn’t quite fit into any category – yes it can do those classic modulated delays sounds (and very, very well too) but can be pushed to do so much more, and in turn, hopefully inspire some new sounds and experimentation.

So here it is: the (as-of-yet unnamed) MI Effects Lo-Fi Delay. A lot of careful design has gone into what goes around the PT chip to give modulation like no other pedal. There is control over the filtering of the delay signal that really gives a new perspective with a flick of the switch, and also the input and output of the pedal carefully honed to give you the control of the best signal-to-noise ratio.

The controls are:

• TIME – delay time up to a max of 600ms.
• REPEATS – go from short, slapback to self-oscillation. The LO-PASS/HI-PASS switch also affects how quickly the pedal will self-oscillate.
• RATE and DEPTH – these control the LFO modulation on the repeats. The RATE goes from super slow to throbbingly fast with a smooth taper for all speeds in between. The Depth also goes from zero at minimum for unmodulated delay, to super warble at maximum. There are some cool octave skipping sounds to be had in square wave mode.
• SQUARE/TRIANGLE WAVE – this switch selects the waveform of the LFO modulating the delay signal. Triangle wave at low rate and depth can give you classic chorus sounds, whilst square wave can give choppy, tremolo sounds, even pseudo pitch-shifting effects.
• LO/HI-PASS MODE – this switch controls the filtering of the delay line. The LO-PASS mode gives dark, analog repeats while the HI-PASS gives clarity to the top-end for shimmering modulation and self-oscillation. Using the LO-PASS mode “smears” the repeats together whilst the HI-PASS mode gives more defined repeats. The production will probably have a 3 position switch for three levels of filtering
• TRAILS ON/OFF – the trails switch allows the control of the trails continuing or cutting off once the pedal is turned off. This is extremely useful to not “cut-off” long delay lines allowing them to naturally decay if switched off mid-trail. Using trails on also allows you to play an atmospheric sound or oscillation, switch the pedal off and play over the top of it, acting almost like a short looper.
• LEVEL – this controls the LEVEL of wet, delay signal whilst having the dry signal constant. This is NOT a mix control.
• INPUT – this controls the INPUT gain of the signal hitting the circuit. This is provided to give you the best signal-to-noise ratio depending on what pickup/guitar/boosters you have in line. Start by setting the INPUT until it clips, then slightly back it off. Raise the LEVEL to taste and you have the clearest signal possible with the lowest floor noise. A bonus is that the INPUT gain can be set to max, and distort your delay line and keep the dry signal clean. This is perfect for stacking with other pedals and the overdrive channel of your amp.

Combining all of these features gives every guitarist, and instrumentalist, a whole new palette of sounds with something there for every guitarist. Modulation can go from subtle to extreme, or have pristine, clean repeats to distorted, washy, smeared reverb-like trails. Use the square wave for choppy, rhythmic pulses or triangle wave for classic chorus/vibrato. I encourage you to dig deeper and get inspired with some new sounds.

At the MI Workshop, I have always wanted to fully trick-out a Crunch Box to see how many mods and features we could fit into its small enclosure.  So one rainy afternoon I did just that, and decided to give three away for our Facebook and Twitter followers.

I was pleasantly surprised with how the Crunch Box sound had evolved with these added features. This, plus the constant feedback from customers wanting this new Crunch Box, led us to prototype the Super Crunch Box.

The Crunch Box has been around for quite a few years now, and has even inspired several clones and knock-offs. So I threw some ideas around the workshop, and came up with a design that expands the flexibility of the original, without an large rise in price.

First Upgrade: 18V Internal Supply
All stock MI drive pedals can be run up to 24V for more headroom, giving more clarity and a tighter bottom end.  We know that a lot of our users run our pedals at higher voltage, but are aware of the troubles of running extra adaptors for these pedals. So a feature I am looking to implement in our future designs is the addition of circuitry to double the input voltage of your 9V adaptor/battery to supply 18V to the pedal. This is a great feature that your pedal board will happy with. The pedal sounds bigger, tighter and more responsive at 18V.

Second Upgrade: External Presence Control
The internal presence control was implemented to integrate easier with every user’s amp setup. Some amps are brighter or darker than the ones we use to test, so by dialling in the Presence control you can control the shape of your sound through your setup. By placing it as an external control, you can really pull some great sounds that sit well in a mix, or to have more control with a range of guitars/amps you might use. The interaction with the Tone control is important as dialling in more Presence can cut really well, but also the lows won’t feel as powerful, so use it with that in mind. This greatly increases the versatility of the Crunch Box, but for those who want to rock it old school, just leave the presence at 50% and proceed as normal!

Third Upgrade: Lo/Hi Gain Switch

This switch adds a great amount of tones that will suit many different playing styles. In Lo Gain Mode, the Crunch Box really cleans up well with the guitar volume knob and has a glassier tone. It still has a lot of gain (it is a Crunch Box after all!) but there is more string definition and top end than Hi Gain Mode. Hi Gain Mode is the stock Crunch Box amount of gain, so you can still get that “hot-rod” sound as with previous versions.

Fourth Upgrade: Clipping Selector
Like the Lo/Hi Gain Switch, this switch aims to tap in to the lower end of the gain spectrum. The switch selects between two different clipping structures, with one still the stock red LEDs as in the original. The other clipping mode provides a softer clipping of the signal, again to provide some flexibility to the overall distorted signal. The softer clipping mode, coupled with the Lo Gain Mode really provides a sparkly, break-up sound that you wouldn’t think comes from a Crunch Box.

I’m proud of the layout of this design and how all of these features were able to be incorporated around the core Crunch Box sound. There are a few hitches we are working through, and a few IC/diode combinations we are experimenting with. Once I’m happy with the outcome, a video demo will go up showing all of these new features. We’re hoping for a mid-year release on this one and for the price to be $149 all things going well, which I’m super excited about, give all the extra features we’re putting in.

Hope you guys like it!

The Megalith Delta high gain distortion pedal design came from years of R&D of our MI Amplification high gain amplifier, the Megalith Beta. It took some time for me to really understand the variables behind great high gain tones. But by designing the amplifier from the ground up, I was able to really grasp how to make a complex, sophisticated high gain sound that kept all the nuances, huge bottom end and the clarity and character of the top end.

The Megalith Delta pedal is a solid state ‘model’ of the Beta preamp, using JFETs to simulate the gain stages of the preamp valves. The transfer characteristics of FETs are very tube-like, so it seemed that this was a great place to start.

This, of course, is not something revolutionary. A quick peruse of the pedal market and various DIY sites will reveal various FET renditions of valve circuits. However, digging a little deeper shows somewhat limited implementations of these circuits. Often, it’s just the exact same circuit as the ‘simulated’ amp, but with FETs instead of tubes, adjusted source or drain resistances, and 9V operation. Little or no thought it given to the operating points, dynamic range, scaling of clipping thresholds, output impedances, and intrinsic capacitances due to things like the miller effect etc.

As you can see, making a FET stage behave like a particular tube stage is actually a very complex affair. One thing which differentiates our endeavour from others’ is the fact that the amplifier in question is our own. I designed every single aspect of the Megalith Beta, and have insights into its working you can’t get by simply looking at the schematic. I know what I wanted every tube stage to do, the logic behind each stage design,… even things like the effect of track and cable capacitance. Because of this, I was able to feed all these parameters into the design, and come up with something which is as close as humanly possible to the original.

Now the controls,…

The GAIN control offers a wide sweep in gain, from low-mid gain rock tones, to serious crunch, to every dark shade of brutal imaginable.

The three-band EQ and EQ SHIFT are taken straight from the amp as well. The EQ SHIFT allows three different voicings by shifting the response of the tone stack.

One of the challenges of doing the Megalith in a pedal format was how to integrate the CONTOUR control into the design. The CONTOUR control, which changes the response of the phase inverter, is what really gives the Megalith amp its flexibility. If you want a loose, fatter, vintage high gain sound – turn up the CONTOUR. If you are after a more modern, tighter and cutting high gain tone – turn down the CONTOUR. So in order to mimic this response, I designed a phase-inverter like stage, and integrated the CONTOUR control into it. The combinations of the EQ section will give an impressive number of high gain sounds, just like the Megalith Beta amplifier.

A BOOST mode was added to the pedal as the amplifier really steps up going from “mid” gain mode to “high” gain mode. I thought by adding this as a foot switch, it gives you the option to really step up the crazy. I also figured that mid to high switching was a lot more useful than low to high, as there are already plenty of great options out there for the lower gain sounds. Lets face it, someone interested in the Megalith isn’t going to be too stressed about missing the low gain mode!

A big part of the Megalith Beta amplifier’s huge gain sound is the 160 Watts of headroom! Of course, this would always be the limitation in trying to emulate a high gain amplifier to stomp box form. But by adding voltage doubling circuitry in the Megalith Delta pedal, it allows the 9V supplied by battery, or DC adaptor, to be increased to 18V within the pedal’s circuitry. This has the advantage of producing the crushing low end without mush, much like the 160W output of the Megalith Beta does at the amp level.

Now, the biggest challenge was working out how to fit it all into a case, and keep it stable. For those of you who haven’t strapped yourselves in for a Megalith ride,… let me tell you, it’s one seriously high gain amp. It’s the only amp I’m aware of that doesn’t need to be driven with a pedal to get a super-tight saturated gain tone. So packing all that gain into a modest pedal enclosure is not only challenging in terms of layout (there are 110 components in the circuit), but also in terms of stability. After a few failed attempts, I moved to a 4 layer layout, with top and bottom ground planes for shielding. This also necessitated a few circuit tweaks to take into account the extra capacitance to ground.

Finally, I designed an output section which is designed to ‘compensate’ for the standard guitar amp’s clean channel response, so that when you plug the Megalith pedal into a ‘reference’ clean amp, you get something close to the feel of the Megalith Beta. Having said that, one of the main aspects of the Megalith Beta’s ‘presence’ is the sheer headroom and output power it has. So no, you probably won’t unleash carnage and devastation plugging a Megalith Delta into a 5W lunch-box amp. That’s just the physics of it,… a reality more inviolable than the existence of fragile harmonics in a crystal lattice.

I feel that, although it may sound cliché, the Megalith Delta high gain pedal is unlike any high gain pedal out there. It came off the back of a complex amplifier design in the Megalith Beta, that already pushes the standard in metal amplifier tones. By emulating the preamp of the Beta, it truly captures the essence of the amp with response and character retained.

Below is a quick demo of the finalised design. It goes quickly from clean, to crunch, to the heaviest of metal tones in under two minutes.

A couple of months ago, we started a Facebook discussion on boost pedals. I was looking at re-designing the Boost ‘n’ Buff and wanted to make THE booster. We got some great feedback on the matter and it became clear that there were two main uses of boost. Some of you prefer the loud, super-clean, super-simple boost, and others preferred boost with some EQ control to add some sparkle to your tone. So, naturally, I decided to design two Boost ‘n’ Buffs!

Since discontinuing the first version of our Boost ‘n’ Buff, we have had a lot of people asking for that simple one-knobber to return – and so it has, in the form of the new Boost ‘n’ Buff Mini. So the same Class A transistor design was packed into the small, finger-size “1590A” sized enclosure with the same feature set; buffer mode in bypass and +40dB boost when engaged. A flat booster for the lower range of the gain control, and treble booster for the higher range. But one added feature gives the Boost ‘n’ Buff Mini something extra. A voltage doubling circuit has also been added to provide the boost circuitry with 18V. This means that when 9V DC is added by power jack (the small size doesn’t allow for battery), the circuit is supplied, internally, with 18V. This gives more headroom and extra top-end sparkle to your signal – all in a tiny enclosure that could fit on any pedal board.

I then wanted to add an EQ feature to the Boost ‘n’ Buff so that it could have the flexibility to be integrated into any set-up. However, I also wanted to avoid the large knob count  my pedals tend to have. So a neat solution involved adding a three-way mini toggle switch to select between three tone-shaping options, whilst still keeping the same VOLUME and GAIN layout from Boost ‘n’ Buff v.2.
The EQ options are:

1. FULL BOOST – This is a full frequency boost regardless of the gain and volume settings. It not only boosts the volume, but seems to really lift your tone as well. It’s difficult to explain. You’ve just got to feel it.
2. TREBLE BOOST - I tuned this mode to be a more of a dramatic treble boost than the stock Boost ‘n’ Buff. I figured that if the full boost option is now available, then it would be possible to make the treble function a bit more prominent.
3. MID BOOST – This came about because I quite liked how the treble boost pushed an already overdriven amp, but for some amps, I found that too much top end made the tone too harsh (For others it was fine). So by rolling off some of the highest frequencies, and beefing up the mids, we were able to get the extra gain, cut and richness, but without the ice-pick.

As well as the added EQ feature, I also added a voltage tripling circuit to boost the pedal’s operating voltage to ~27V! Unlike the Boost ‘n’ Buff Mini, v.3 does have room for a 9V battery, and will internally triple the supply voltage of either battery or DC adaptor supply.

Here is a demo we recorded of the prototype Boost ‘n’ Buff version 3. We tried to show the amount of boost on tap and the different EQ voicings for each of the three modes into the clean and overdrive channel.

The initial idea was to try to make an overdrive as smooth as possible, but after tinkering with it a bit, it’s morphed into something else altogether. This isn’t modelled on anything in particular but we were shooting for a few things:
1) A very natural response, both in terms of tonal balance and overdrive feel.
2) Unlike opamp based pedals, I wanted something that when you roll back on the volume, the sound is virtually clean, but also balanced.
3) Touch response.
4) high gain sounds to have a big footprint, but with a vintage vibe to them,… what I’ve heard referred to as the 1000lb violin

At its lowest gain, it is a boost/enhancer adding some extra sparkle to your guitar tone. Mid gain mode gives some nice, complex, tube-like overdrive but allows clean-up of your signal via the guitar’s volume knob that A/Bs well against your standard clean. Crank the gain and you have a smooth, harmonic-rich, sustaining lead sound from 70′s rock to jazz-fusion.

Here is a demo we made with a Les Paul > FET Overdrive > MI Amplification Iron Duke…

This demo with two Strats > FET Overdrive > MI Amplification Iron Duke…

It is always great when a prototype delivers what you want to hear, and this one did. We were undecided on whether this would be a pedal we would put into production, but due to the positive feedback we have received from the demos, we will be continuing with it.

However there are a few tweaks needed before a production-ready pedal can be made:

• The tone control is the standard MI mixing tone control. I felt it needed it just so that you could adjust the top end as the gain goes up (as clipping increases, so does the higher frequency content). Having it at a fixed setting would mean either that the low gain sounds were too dark, or that the higher gain sounds were too bright. I’m experimenting with taming the top end with a three-position toggle (as in the Neo Fuzz/GI Fuzz) so that it can be matched no matter the guitar/amp set-up.
• The gain control sweep needs fine-tuning so that at minimum settings it is clean and a more gradual increase in gain from there. At the moment, all of the sweep is from 9 o’clock to 2 o’clock.

Keep posted on the blog for the next prototype iteration with the new tweaks, and a new demo.

- Michael I.

A caveat first: NOT ALL OF THESE DESIGNS WILL MAKE PRODUCTION.
For various reasons, so some of these ideas will be shelved, others will evolve into other projects. So please refrain from questions like “When will this be released?”, “Or can I buy the prototype?”. As much as we would love to have that information, it really depends on a whole constellation of factors, so any releases will come in good time. Please enjoy the read, and let us know if you would like to see this on your pedal board.

We’d love to hear your feedback along the way, by comments on each post, or via our Facebook page and Twitter. We hope that those interested in design will get some knowledge along the way, and those simply interested in MI Effects will get a sneak peek into what will be released in 2012.

Thanks for your support and see you on the comments page!
-Michael I