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Big Briar Moogerfoogers

Pedal-based Voltage-controlled Processing System By Chris Carter
Published February 2002

Since 1999, Bob Moog's Big Briar company has been making analogue filters and effects pedals based on his original Moog module designs. Now there's a central control unit, so that you can use them all together as a complete processing system.

Unless you've been hiding under a rock for over 30 years, are only eight years old or have picked up this magazine thinking it was about yodelling, then you must at least recognise the name Bob Moog, probably the most famous name in electronic music. Although the Moog Music company and its once‑famous Minimoogs and modular systems are no more, Moog himself has survived on the fringes of the industry, and since the early '90s, his Big Briar company has been busy producing Theremins and other such esoterica for the discerning electronic musician.

Big Briar MoogerfoogersIn recent years, Big Briar have produced the award‑winning Moogerfooger range of analogue effects and processors. These oddly named units are all direct descendants of the original Moog systems' analogue circuit designs and contain many of the basic building blocks of modular synthesis. The Moogerfooger processor family now comprises five: the MF101 low‑pass filter, the MF102 ring modulator, the MF103 12‑stage phaser, the MF104 analogue delay, and the CF251 control processor. Exciting times are also ahead for Big Briar, as they're about to relaunch the legendary Minimoog as the Minimoog Voyager, a new analogue/digital hybrid version of the original.

For the moment, though, it's the Moogerfoogers that concern us. The four effects processors each live inside chunky oversized 'stomp boxes', approximately nine inches by six by three, made of steel with real hardwood end cheeks and traditional Moog‑style knobs, rocker switches and tri‑colour LEDs. Around the back of each unit is a multitude of jack sockets for interfacing with other Moogerfoogers, the CF251 control processor, footpedals, MIDI‑to‑CV units, or other analogue gear. All the Moogerfooger units are powered from standard 9V wall‑wart adaptors, and although it is obvious from the stomp box design that they're all primarily intended for the guitaring fraternity, I have a sneaking suspicion they are going to find themselves hooked up to quite a few keyboards, samplers and mixers too. Being a keyboardy type myself, that's exactly what I used for this review.

MF101 Low‑pass Filter

If, at this point, you are experiencing feelings of déjà vû, that's because Paul White first reviewed the Moogerfooger low‑pass filter in SOS April 1999. However, for those of you without that review to hand, I'll briefly go over the basic functions.

As you can see from the photos, the layout (which is pretty much the same on all the units) is relatively basic with just five or six knobs and a couple of rocker switches.

The circuitry comprises a switchable analogue two‑pole (12dB‑per‑octave) or four‑pole (24dB‑per‑octave) low‑pass filter with knobs for Cutoff frequency, Resonance and Drive (input gain). The filter can be controlled by an internal envelope follower with adjustable envelope amount and a switchable envelope Response (fast/smooth). A Mix control is included for blending the filtered and unfiltered sounds.

The rear of the MF101, like all the Moogerfoogers, offers an unusually high number of sockets for a 'stomp box'. In this case, there are jack connectors for mono audio in and out (naturally), plus an Envelope Follower voltage‑control output and voltage‑control inputs for Cutoff, Mix, Resonance and Amount. The voltage‑control inputs can accommodate any standard 0 to +5V variable control source, such as you would find on the majority of ancient and modern modular synths.

As analogue low‑pass filters go, the Moogerfooger can't really be faulted, but then again this is a Moog design, so you'd expect that, wouldn't you? I certainly did. And with the right material, I doubt you'd be disappointed. But to get the best out of this filter (like most filters, really) you need to give it something rich in harmonics, such as a raw square, sawtooth or pulse waveform. Distorted guitar and complete mixes are also good sources for low‑pass filtering. The four‑pole setting is my favourite and has a warm, deep quality, while the two‑pole setting gives a slightly brighter but still very pleasant sound. Cranking up the Drive and Resonance controls emphasises the 'Moogy' quality of this filter, and turning the Resonance knob to maximum causes the filter to self‑oscillate. The word 'sweet' springs to mind when listening to this VCF, although you have to keep your eye on the input level LEDs to avoid serious overloading.

The envelope follower option, which imposes the amplitude of the input signal on the filter cutoff, is useful in certain circumstances, though I have to admit I didn't use it much in this review and instead opted for manual knob sweeps and external voltage control. It could be a useful tool for guitarists, however, as it follows the amplitude of your playing. The case isn't so clear‑cut for keyboard players, though, as auto‑envelope following (as opposed to true keyboard triggering) can be a bit of a hit‑and‑miss affair.

I would like to have seen a basic LFO (low‑frequency oscillator) included in this unit for sweeping the filter range, but this is a situation where the LFO in the CF251 Control Processor could be patched in (more on this later).

MF102 Ring Modulator

The Ring Modulator has the same physical layout as the filter, but is an entirely different beast and contains all the features you need to create classic metallic, discordant ring modulator sounds and effects.

In case you don't know what a ring modulator does, it basically takes two different signals (known as the Carrier and Modulator) and creates new signals at frequencies based on the sum and difference of the Carrier and Modulator frequencies (for more on ring modulators, see Part 11 of Gordon Reid's Synth Secrets, in SOS March 2000.

In the MF102, any sound you feed into the audio input becomes the Modulator, while the Carrier is usually an internal VCO with a switchable sine/square wave output, although there is also an audio input which allows you to disregard the internal VCO and supply your own Carrier as well. If you do use it, the internal VCO can in turn be modulated by an internal LFO or an external voltage. Controls are kept to a minimum with a Frequency knob, Frequency range switch (Low & High), the Sine/Square switch for the VCO, a Rate knob with LED, and LFO Amount. The balance of treated and untreated audio signal can be adjusted with a Modulator Mix control and a Drive knob governs the level of the audio input.

Around the back are sockets for mono audio in and out, voltage‑control inputs for LFO Rate, LFO Amount, VCO Frequency and audio Mix, and control‑voltage outputs from the LFO and Carrier (VCO). There's also the aforementioned Carrier In socket. All in all, it's a comprehensive range of facilities.

It's not all roses, though. One slight irritation is that the MF102 includes an undocumented automatic noise gate on the audio signal, or 'squelch circuit' in Moog terminology. The reason for including this feature is understandable; it's to help suppress oscillator breakthrough (ie. the unwanted presence of the original Carrier in the output signals); an unavoidable side‑effect of using analogue circuitry. The problem is that there is no control over how the noise gate functions, and it can cut off the tail end of some soft sounds. Despite this, oscillator breakthrough is still occasionally audible with little or no signal present!

This is undoubtedly the Moogerfooger with the greatest potential for sonic mangling, and, unlike the low‑pass filter, you don't have to be selective with your choice of material to get results. You may need to spend some time tweaking controls to get the best out of it, though; the Mix and Drive knobs, for instance, can drastically affect the depth of ring modulation.

The MF102 is quite capable of producing all the usual metallic clangs and harmonic sweeps, and you can also use it for subtle tremolo and slow modulation effects. Connecting the rear CV inputs to other Moogerfoogers or CV‑capable systems opens up a whole new range of ring‑modulating possibilities too.

MF103 12‑Stage Phaser

This processor contains an LFO and a switchable six‑ or 12‑stage analogue phasing circuit. There are controls for LFO Amount and Rate plus a High/Low rocker switch for the LFO speed, which is also indicated by a flashing LED. The Phaser section has a Sweep knob so you can change the phasing effect manually, a Resonance control for a deeper and more pronounced phasing effect and a rocker switch to select six‑ or 12‑stage phasing. There is also an input Drive control, an Output Level knob and a tri‑coloured LED to help you set the optimum audio input level.

I should briefly explain the differences between the two phasing modes. In six‑stage phase mode the audio signal is fed through a comb filter which has three distinct frequency dips, or notches. There are intervals of about two octaves between these notches, and when the centre frequency is swept or modulated you get that classic analogue phasing effect, as heard from the most phaser pedals. The Moogerfooger takes this a step further and offers the option of doubling the number of frequency notches the signal has to go through. The result is a much more pronounced phasing, and is quite similar to the rarely heard so‑called 'barber pole' effect, in which the phasing seems to continually rise (or fall) without end. But as with all phasers, the effect is only really apparent if the phase frequency is continually moving, either being modulated by the LFO, via the external CV input, or being swept by hand.

Although the MF103 is really only a one‑trick horse, with combinations of deeper and shallow and/or faster and slower phasing, it is also one of my favourites in the range. In either mode, but particularly on the 12‑stage setting, it can impart a very analogue and extremely pleasing musical timbre to a sound. Unique amongst the Moogerfoogers, it also includes an additional inverted audio output. When used in conjunction with the normal output (with one panned hard left, and the other hard right), this can give a pleasant stereo phase‑shifted panning effect.

MF104 Analogue Delay

This type of delay unit is quite a rarity these days, as it uses old technology (by today's standards, anyway) that is no longer in production — namely 'bucket‑brigade' integrated circuits. Big Briar have managed to track down the last remaining stocks of these special but once common items and are producing a limited edition run of just 1000 Analogue Delay processors. Coupled with the Moog name, this pretty well guarantees that the MF104 will become a collectable item.

Using the Loop function on the MF104 with the control processor (patched here to use the CP251's sample & hold module).Using the Loop function on the MF104 with the control processor (patched here to use the CP251's sample & hold module).The top panel layout is the same as the other Moogers, but instead we have controls for Delay Time, Feedback, Mix, Drive (input level with tri‑coloured LED) and Output Level. Also included is a Loop Gain control and LED (of which more in a moment) and an Internal/External Loop rocker switch.

One drawback with analogue delays is that they have a much lower audio bandwidth compared to digital delays (often less than half). To most modern ears, they are therefore an acquired taste, and can sound muffled and decidedly low‑tech. However, with the right kind of music, and in the right situation, such as when playing live or adding 'warmth' to digital instruments, they can be just what the doctor ordered.

Voltage control of many parameters is offered, including external control over mix, feedback and delay time. If you've not played with an analogue delay before, you might find tricks like sweeping the delay time on the fly without digital noise or stepping artefacts a real revelation. It may not be an effect that suits all types of music, but it's great for dub and experimental electronica. Used at the minimum delay time settings, the MF104 will produce flanging, while at the mid settings you can get it to simulate 'boingy' spring reverb‑type sounds. The maximum delay is a respectable 800mS, and is eminently suitable for spacey Robert Fripp‑type effects.

The Loop option is nothing to do with sampling and breakbeats, but allows you to re‑route the delay feedback signal out of the audio chain and into an external processor, after which you can insert the effected signal back into the feedback path. If you use the Loop Gain control carefully (to set the gain of the signal sent to the loop) and choose the right kind of external processing, the results can be quite unusual. For instance, if the Loop option is used to send to and return from the Ring Modulator, and a sound is played into the Delay processor, the original signal is heard as it should be, but the delayed echoes are increasingly ring‑modulated with each repeat. The Loop feature works best with an external effect that has a pronounced effect on the sound, such as the phaser or ring modulator, but it doesn't work so well if you use the low‑pass filter.

Voltage‑control Inputs

The voltage‑control inputs on all the Moogerfooger audio processors use three‑conductor, ring/tip‑type jack sockets. The ring terminal is supplied internally with +5V and if the right kind of expression pedal is correctly connected to the voltage‑control inputs (details are in the instruction manuals), it can be used as a constantly variable control source.

The CP251 Control Processor also includes eight of the same ring/tip sockets (in the LFO, mixer, sample‑and‑hold module and the attenuators), and thoughtfully, the sockets are coloured red. The informative instruction manual suggests that these should provide the experimentally inclined with a wide range of control possibilities.

CP251 Control Processor

This unit is the odd one out of the Moogerfooger family, in looks and features. As you can see from the picture on the next page, it doesn't have the same sloping 'stomp box' style of the other units, and although it is approximately the same size, it is also quite a bit heavier. It can also be used on its back or standing upright, in which case the power plug can be inserted in a second 9V socket on the base plate — a thoughtful design touch.

The CP251 is divided into roughly eight sections: a four‑input mixer, a lag processor, an LFO, two attenuators, a noise generator, a sample & hold module, and a four‑way multiple group of jack sockets.

Although the instruction manual states that this is solely a control processor and has no audio input or output sockets, this isn't strictly true, as the CP251's noise source can be connected to the audio inputs of the other Moogerfoogers, and the four‑input mixer and attenuators can also be used with audio signals. However, it is true that the CP251 is primarily intended as a voltage‑control source or modifier for the CV inputs and outputs of the Moogerfooger processors, or other analogue or voltage‑controllable gear.

Unless you've come across modular synths before, some of the CP251's features may be unfamiliar, such as the sample & hold module, the lag processor and the attenuators. The attenuators are simply for reducing the level of a CV signal, although unusually the degree of attenuation itself can also be controlled by another CV source. The lag processor provides a means of slowing down a fast‑changing control waveform such as a square wave. Two knobs adjust the rise rate (the leading edge) and fall rate (the trailing edge) of the incoming signal. This is a handy feature for changing the shape of basic waveforms that are controlling other Moogerfooger CV functions; for example, a square wave could be modified into a normal (or inverted) sawtooth or triangle waveform.

The four‑input control signal mixer does what it is supposed to, but only inputs 1 and 2 can be attenuated; inputs 3 and 4 are mixed at their maximum level. However, the mixer output stage includes a Master Level and an Offset control for shifting the mixer output control voltage in a positive or negative direction. A useful inverted output is also included.

Despite the fact that the sample & hold module only has two inputs ('In' and 'Trig'), two outputs and no knobs, it is a very useful control‑voltage source. Before the modular‑synth novices amongst you get too excited, I should point out that this module doesn't offer digital audio sampling; instead the term refers to the process of sampling the moving or random voltage applied to the input and then outputting that signal until a new voltage is sampled. The sampling action commences when a trigger signal crosses a preset threshold at the trigger input. Depending on the sample and trigger source the outcome is a random stepped effect at a constantly changing rate, and is most often heard controlling a VCF or VCO.

The sampling source for the S&H In socket is an internally patched connection to the Noise generator output while the Trig input socket is internally connected to the LFO square wave output, but both these connections can be overridden by inserting a jack from an external CV source. S&H Out 1 carries a normal CV signal while Out 2 reaches the outside world via a special low‑pass filter which smoothes out any signal peaks. The filtering feature on Out 2 is also directly related to the LFO/S&H trigger speed — the faster the rate, the smoother the CV output. The S&H module works well, although I'd have liked a variable threshold control on the Trig input. The separate Noise socket generates a straightforward random white noise signal suitable for feeding into the audio input of other Moogerfooger audio processors.

The four‑way multiple module's jacks are all connected in parallel and allow CV inputs or outputs to be used by more than one destination, which is exactly what you'd expect it to do. Finally, there's also an LFO, which is a fairly basic affair with independent sine and square outputs, although it also has a voltage‑controllable rate.

Nice, But At A Price

Apart from a few idiosyncrasies like the lack of a true bypass function (the circuits are always active) and the decidedly mono bias the Moogers get a thumbs‑up from me. As I said earlier, my favourite effects are the phaser and the ring modulator, but my ideal setup would be to use all of them as a rudimentary Moog modular system (see box on this earlier in this article), and I'm sure the less cash‑strapped of you reading this will take that route. And this leads me on to the most common criticism I heard while I had the Moogerfoogers for review; their price compared to other manufacturers' processors. I have to say that this is also my only serious concern. Admittedly, the range oozes quality and is obviously aimed at the professional gigging musician, but the complete set is going to set you back a not‑inconsiderable £1540. And that gives rise to another dilemma — would you use a £500 limited‑edition analogue delay pedal as a stomp box on some manky old stage? Personally I wouldn't dream of it, but that's just my opinion.

And there's the rub — ultimately the decision is up to you. If money is no object, then you should know that the Moogerfoogers sound great, are well built and have an adequate, if basic, feature set. On the other hand, to me at least, £300 is a lot of money to pay for a mono phaser, no matter who made it.

The Pedal‑based Moog Modular?

When used in combination or connected together, the Moogerfoogers really shine and are not unlike a real Moog modular synth system, albeit a small one. The number of patching permutations and configurations is almost endless, and at one point I found myself using more than a dozen patch cords for a totally mad but great‑sounding setup — and that was without using any expression pedals!

But unfortunately, using them in this way also highlights one of the major failings of the Moogerfooger 'stomp box' design — accessibility. As 'patched‑in' guitar or desktop/keyboard effects units the design is fine; you just plug them in and play. The Moog literature describes using the units as a 'modular analogue synthesizer' and all those wonderfully versatile CV inputs and outputs cry out for experimentation, but when using several units together, the need to lean over and patch via the rear panels becomes a major pain in the neck (literally). So why is the CP251 Control Processor unit — a model of logical design with everything accessible on one panel — the only Moogerfooger available in this configuration?

You can see what I'm driving at — I'd love to see all the Moogerfoogers also available in a true desktop modular design along the lines of the CF251, and possibly interlockable or stackable, for that real hands‑on Moog modular patchability experience. I'd also be a very happy chap if there were a socket for a remote bypass switch, not just the expression pedal option, so they could be tweaked from a desktop or keyboard and still be foot‑activated.

In short, I think Mr Moog should also give some thought to non‑guitar‑toting, non‑stomping, electronic musicians. Go on, you know it makes sense!


  • Excellent, authentic analogue sound.
  • A true 'plug‑and‑play' system.
  • Well‑chosen connectivity options allow a wide range of processing possibilities.
  • Can be used in combination to make a basic Moog modular system.
  • Rugged build quality.


  • Mono only.
  • No true effects bypass; circuitry is always active.
  • Expensive.
  • 'Stomp box' design may not appeal to everyone.


A very respectable range of simple‑to‑use, great‑sounding analogue effects units, with a higher‑than‑usual quota of interface sockets for a stomp box. Include the Control Processor in the equation and you have a rudimentary Moog modular system. Nice, but undeniably pricey.


MF101 £219; MF102 £219; MF103 £299; MF104 £499; CP251 £299. Prices include VAT.