Moog Moogerfooger analog effects


Update 07-07-2012

MF-101 Lowpass
MF-102 Ring Mod
MF-103 Phaser
MF-104 Delay
MF-105M MIDIMurf
MF-108M Cluster Flux

Bob Moog's first entry into the commercial market under his company Big Briar (later Moog Music) was the Moogerfooger line of effects pedals.  They are designed for guitars, keyboards, drum machines, or any audio application.  Many have complained about the prices of the floor stompbox format, but these are professional low noise wide bandwidth audio processors with features not found on other stompbox effects. 

For those curious about the origin of the name, Bob had visited a studio and noticed one of the mixer channels was labeled "moogerfooger".  He learned that the owner had a heavy Brooklyn accent and this label was the translated from his pronunciation of a very unflattering metaphor.

The first of the pedals were the MF-101 low pass filter and MF-102 ring modulator which were released in 1998.  While they are not the first devices of their kind they were the start of the Moogerfooger tradition of voltage control of device parameters.  Bob Moog pioneered the concept of voltage control in the synthesizer industry and with the Moogerfooger line he extends it to effects processors.  Besides voltage control, these devices are well featured.  The later devices (with the "M" suffix) would incorporate control of parameters over MIDI, ushering in the 21st century.

All the Moogerfooger pedals feature an input gain control to provide 35dB of gain, which will accommodate anything from low-level guitar to (+)4dBm line level sources.  A tri-color LED shows green for signal presence, yellow for low level overdrive, and red for distortion/clipping.  Overdrive is purposely built in and designed to be warm sounding, while increasing the gain will generate stronger distortion and will eventually clip the internal circuits.  So if you are dealing with a percussive signal and want to exploit the overdrive, it will take a little experimentation to find the gain setting that sounds good to your ears.  Otherwise your optimum gain setting is where the LED occasionally blinks yellow.  This is a nice compact indicator of gain while keeping the signal to noise level reasonable.

Voltage control is provided at TRS jacks on the rear panel.  They can be used with passive attenuators such as CV (control voltage) pedals consisting of a simple pot - the ring supplies the (+)5.7VDC source which is current limited to 0.5mA, the tip receives the attenuated voltage from the pot, and sleeve is ground.  The full range of the CV-able pot can be accomplished with a 0VDC to (+)5VDC range at the CV jack.  Active CV sources such as sequencers, analog synthesizer modulation sources (such as sample-and-hold), or MIDI-to-CV converters can be used by wiring a TRS plug with the ring left unconnected.  A TS plug can safely be used as the current limiting with ring shorted to ground will prevent damage, but it will also render the ring inactive (and other passive attenuators) at the other jacks.  Besides external CV modulation, these CV jacks allow the device to be pseudo-programmable by turning all the CV-able knobs fully counterclockwise, connecting their CV jacks to a MIDI-to-CV converter, and using MIDI messages from your MIDI sequencer to "program" the device in real time.  Rocker switches and the input/output level controls will not have voltage control.

A footswitch bypass the processor circuit, with an LED indicating active or bypass status so you can tell at a glance whether it is active.  The footswitch is rugged enough for foot operation while easy to press with the thumb, so the Moogerfooger can be used on the floor or on the tabletop.  The bypass is buffered and not a true bypass.  Many guitar players are biased against buffered bypass because they don't want anything to alter their tone.  Many guitar players also believe anything they hear/read and there are many myths surrounding the guitar industry (professional artists often are the source of these myths as they don't want copycats on their trail - Eddie Van Halen* and Billy Gibbons are notorious for this practice).  Bob Moog has had design experience with guitar processors - when the 1970s Moog Music was part of the Norlin conglomerate Bob designed the Lab Series amplifiers and the wedge-shaped Maestro stompboxes. 

Bob chose the buffered bypass for an important reason - it significantly reduces the effect of cable capacitance.  The high output impedance of guitar pickups combined with the capacitance of cables form a lowpass filter that robs your guitar of high frequencies.  Cable capacitance is specified per foot so the longer the cable the worse the loss of high frequencies - the loss can occur with cable as short as ten feet.  With true bypass, a chain of stompboxes all add up to the equivalent of a very long cable and you start losing high frequencies.  But with buffered bypass, the output impedance is now low impedance which renders the effect of cable capacitance ineffective.  Therefore guitar players have it the wrong way around - it is true bypass that alters the tone of their guitar, not buffered.  Does the Moogerfooger buffer circuit alter the tone?  Consider the designer - Bob Moog.  He has a long history of audio circuit design with input from musicians and is no slouch with music devices.  If anybody is going to get the bypass buffer designed right, he's your man.

Many stompboxes are powered from compact batteries and thus suffer from design compromises that sacrifice signal-to-noise level, headroom, frequency response, quality of the effect, and depth of features.  Because the Moogerfooger line is powered from a beefier power source in the form of a wallwart, there is plenty of power to design quality and features into the devices.  The power source must supply 300ma at a regulated voltage from (+)9VDC (some of the devices will tolerate up to a maximum of (+)12VDC, some up to (+)15VDC, some no higher than (+)9VDC.  So much for convention). The tip of the power connector is positive.

MF-101 Low Pass Filter


Now I have PLENTY of lowpass filters in my arsenal, particularly the Moog Ladder variety.  Why would I need another one?

I was recording our jazz band and the tone of the bass player had too much upper midrange, enough to conflict with the snare drum.  EQ didn't help.  I did try using the Minimoog filter with its external audio input but the effect didn't sound right.  And I didn't want all that cabling presenting a trip hazard.  Then I was wandering my favorite haunt for used gear and they had a used MF-101 with EP-1 pedal and gigbag.  It dawned on me that the 12dB/oct slope might be the ticket to tame that bass.  Indeed it was - the 12dB/oct (2 pole) slope sounded better than the 24dB/oct (4 pole) slope found in most Moog synthesizers.  While it gently rolled off the upper midrange, it also firmed up the low end and resulted in a great sounding bass tone.  12dB/oct doesn't roll off the cut band harmonics as sharply as 24dB/oct, which is why it sounded better for a bass guitar.

Not that there was anything wrong with the 24dB/oct slope - it is all a matter of application.

Besides correcting bass timbres, I have a future application for this box.  I have some MIDI orchestrations in the works, and I want to use this box to dynamically change the timbre of my static samples from my Kurzweil romplers.  Those Kurzweils have no on-board filter and I wanted the timbre to change with volume/breath pressure like the real thing - this required an envelope follower.  I had nothing in my arsenal that contained an envelope follower, and that is where this box will fill that gap.

The filter has a nice resonant color in either 2 pole or 4 pole mode, and its cutoff AND resonance can be voltage controlled.  This feature alone is excellent for shoehorning into a synthesizer if you have filter(s) that are weak sounding.  The envelope follower generates a control voltage that corresponds to the amplitude of the input signal.  This control voltage is applied to the filter cutoff via the AMOUNT control, and that control voltage is available at a rear panel jack (YAY!).  It has a FAST and SMOOTH response - the difference is how closely the envelope tracks the amplitude.  FAST is near instantaneous, while SMOOTH has added rise/fall time to the response.  The latter is best for stringed instruments with rapid transients, while the former is best for instruments with slower transients like strings, reeds, and brass.  You can use the MIX control to blend from 100% dry to 100% wet.  Rear panel jacks provide voltage control of mix, amount, cutoff, and resonance.  A nicely rounded out pedal.

This one is one of the early Big Briar models - the company under which Bob operated until he regained his namesake trademark back and changed it to Moog Music - easily identified with the facsimile "Bob Moog" autograph on the face instead of the moog logo.  From the IC datecodes this specimen was built in 1999.  But hold on, there is an interesting component in here - a CA3080.  These haven't been made since the early 2000s, so later models would have had a component substitution due to an obsolete part.  The 3080 is an OTA that was commonly used during the 1970-80s as VCAs and as control elements for filters in analog synthesizers.  As famously used in Moogs and Oberheim SEM-based designs, the 3080 could be driven (and indeed was) into nonlinearity to impart a subtle overdrive on the signal, which is one reason that vintage synths have a high end "sheen" that is missing from modern analog synthesizers.  Since the filter resonance can be voltage controlled, the obvious application for that 3080 was in the feedback path of the filter which had been utilized in previous Moog models such as Source and Memorymoog - both which exhibit that vintage "sheen".  If I find one of the later models it would be an interesting comparision between the two.

MF-102 Ring Modulator


The Ring Modulator is the oddball of my collection and is best at special effects.  The ring modulator concept produces sum and difference harmonics from a carrier oscillator (built into the unit) and a modulator signal (your audio source).  The audio results can be quite clangorous (bell-like) and can range between the extremes of radical and musical.

To clarify how Ring Modulation works, assume a carrier signal consisting of a sine wave at 500hz, and the modulator signal another sine wave at 100hz.  The sum of these harmonics (500 plus 100) is 600hz and the difference (500 minus 100) is 400hz.  The resulting sum/difference set of new harmonics have little to no audible harmonic relationship to their original signals.  The original signals are suppressed from the ring modulator output although you can blend your audio source with the mix control.  More complex harmonics can result using non-sinusoidal waveforms, which is where your audio source comes in. The Ring Modulator can transform waveforms of simple harmonic structure such as square or triangle waves into complex waveforms, a good tool for generating complex LFO waveshapes for your synthesizer.  The result resembles amplitude modulation, and in fact guitar-style tremolo can be achieved by configuring the modulator at very low frequencies.

If you manually sweep the modulator frequency up and down you will hear the sum/difference harmonic sets sweeping up and down.  If you hear harmonics at one extreme reverse direction, they are going "through zero" and the frequencies become negative.  In the audio domain negative and positive frequencies sound the same, it is the sweep through zero frequency that is the special effect.  This is one of many special effects that this puppy can do.  This "sweep" effect can be done automatically using the LFO, whose rate is indicated with an LED. The LFO supplies square or sine waveforms with an adjustable rate of 0.1hz to 25hz and adjustable modulation depth ("Amount" knob).

This box has a generous rear panel.  The outputs of the LFO and the carrier oscillators are available at separate jacks for use as modulation sources for external devices.  The LFO output swings at +/-1.5V while the carrier at +/-1.25V.  Since the carrier can be frequency modulated with the LFO this can be an interesting modulation source for your analog synthesizer or another Moogerfooger device.  Also included is a carrier input jack which replaces the internal carrier source with another audio source of your choice, with best results at (-)4dBm (or 0.5Vrms).  Under this condition, keep in mind that if either audio source is muted then so is the output.  This permits another talent of the Ring Modulator - a frequency doubler.  If you apply the same signal to both carrier and modulator, the difference is zero while the sum is double resulting in a pitch an octave higher (although higher harmonics may be attenuated due to the limited bandwidth of the IC performing ring modulation).

The CV jacks on the rear panel provide remote control of carrier frequency, LFO rate, LFO amount, and Mix.  If you have the Moog Voyager with the VX-351 option then you can use the envelopes, LFO, pitch bend wheel, S&H, touchpad X/Y/Z et al to go hog wild with this box.  This thing can get really sick.

The Ring Modulator and Low Pass Filter are the only Moogerfooger processors that do not have an adjustable output.


MF-103 6/12-stage Phaser


This box harkens back to the days of 1970s - an OTA-based phase shifter configurable into 6 stage or 12 stage.  I would place its phasing sound between the MXR Phase 100 and the Mutron BiPhase.

Phase shifting produces comb filter effects, so named because the frequency response (aka spectral result) of multiple peaks and dips resemble the teeth of a comb.  In its static form, the audio result is akin to feeling your ears being twisted from inside your head.  Actually a static phase shift is very common in certain rooms, in the right point of reference, where the reflective ambience can cause the same comb filter effect.  A phase-shift "stage" is the circuit element that provides (n) degrees of phase shift.  Single phase shift stage is a very subtle effect and not at all interesting.  Multiple stages configured in series can produce thicker sounds, so a 12 stage produces the thickest sound (has more peaks/dips in the spectral result) while the 6 stage is a pronounced gentler effect.  The Mutron BiPhase is one of the other few phase shifters that can be configured as a 12 stage.

Much more interesting sounds result from sweeping the phase shift automatically via the LFO.  The LFO is a simple affair with only sine waveform with rate and amount control, although you can replace it with another LFO of your choice (or any synthesizer modulation source such as touchpad or sequential controller) with the SWEEP IN jack on the rear panel.  The LFO can sweep from a barely discernable one cycle every 100 seconds (0.01hz) to way in the audio range (250hz) - the widest range in the Moogerfooger line?  The LFO sweeps the peaks/dips across the frequency axis while maintaining the displacement between peaks/dips.  The rate of the LFO has a wide range from very slow (for barely perceptable phase shifting) to very fast (appraoching ring modulator effects).  AMOUNT varies the depth of modulation from the LFO and is often omitted on most stompbox phase shifters.  Rate and amount can be voltage controlled from the rear panel jacks, and the LFO output is also available at the rear panel.

The SWEEP control sets the initial frequency centers of the peaks/dips, while the RESONANCE control varies the depth of the dips (I may trademark that phrase!) and the sharpness of the peaks.  Both of these can be voltage controlled via the rear panel jacks.

The AUX OUT provides a stereo effect - the spectral result is the peaks/dips are reversed as that of the AUDIO OUT and the extreme low and high spectra are heavily attenuated.  This is not an out of phase output which is a common stereo "cheat" among less expensive processors.  Out of phase stereo signals will cancel when summed to mono, but the MF-103 does not suffer from this.


MF-104 Analog Delay


This is the original 800ms MF-104 analog delay last made in 2001 (not the later 1000ms MF-104Z or 1400ms MF-104SD).  There were 1000 of these units produced and they are the most sought after of the moogerfooger pedals on the used market.  The limited production was due to the limited supply of BBD ICs, which at the time were being obsoleted by the manufacturer.

Two delay ranges of 400ms and 800ms are offered, the longer delay at the expense of decreased high frequencies.  This is a typical tradeoff of analog delays because longer delay times require slowing the delay clock driver into the audio domain, thus clock feedthrough must be filtered out before it reaches the audio output.  This is not always a bad thing as it can emulate natural echoes which are not full fidelity in nature.  Moog doesn't provide a specification of frequency response, but the shorter 400ms range seems to top out at 12Khz and 800ms at 6Khz.

Nothing earth-shattering about the analog delay controls - delay time, feedback, and mix all which are voltage controllable.  At feedback above "8" it will feedback on itself, which can be a cool effect that can be varied in real time by manipulating the feedback and/or delay time controls.  However they did neglect to include negative feedback.  The interesting feature is you can insert the processor of your choice in the feedback loop.  The manual suggests the MF-102 Ring Modulator but that sounds really radical (I may try it with S&H modulating the carrier).  High pass filters work well for rolling off the low frequencies, which what echo in nature sounds like.  Loop Gain compensates for passive filters such as tank RLC circuits.  I have also found the MIDIMurf useful in the feedback loop, especially when using the pattern sequencer.

The rear panel provides both mix and delay outputs, the latter a handy feature.  If you set the mix 100% dry, you can route the delay only signal to a separate mixer buss or to a stereo amplifier setup.  The Moog crew had some good input from musicians to have included this.

I own two of these - these things sounded so good that I acquired a second one back when they were still available.  In hindsight it was a wise decision as the yet-to-be-produced Moog Voyager was to have dual filter stereo outputs, and these two analog delays sound awesome on the Voyager stereo outputs.  In fact the earlier unit used the MN3005 BBD device, while the later one the MN3008.  I haven't closely examined the PC boards for any difference, but the part number etched on the boards do have differing revision letters.

My only beef is that the MF-104 doesn't produce shorter delays than 40ms so you can't do Haas processing, chorus, or flange effects (that would later come in the MF-108M).

I have never heard the MF-104Z or MF-104SD so I do not know if there are any sound differences.  The easiest way to tell them apart is the MF-104 has Bob Moog's facsimile signature on the front panel, while the others have the moog logo.



The MIDIMuRF is a MIDI controlled filter bank, effectively a merging of the non-MIDI MF-105 and MF-105B.  There is a lot of power under this simple box.

There are eight resonant bandpass filters whose outputs can be attenuated via the slidepots, and a switch toggles the center frequencies of each filter between those optimized for bass or guitar.  While it looks like a graphic equalizer, there are important differences.  The filters in the MuRF are purposely designed to be resonant so they color the sound, the slidepots vary from unity gain to zero output, and the filters are tuned so that adjacent bands do not overlap.  The graphic equalizer is designed with minimum color, the filters of each band are not resonant, and the slidepots will not completely mute the band.  The graphic equalizer is designed as a correction device with boost and cut control to minimize color, while the MuRF is designed to intentionally color the sound but with only cut control.

Included in the MuRF is a cyclic pattern generator (labeled ANIMATION on the front panel) which can be controlled and configured over MIDI.  The pattern generator is an eight channel 64 step sequencer with each channel enabling or muting the independent filters, and each channel has its own independent envelope (triggered by the sequencer) which shapes the volume of each filter.  The MuRF is delivered with a factory set of 24 preset patterns (12 for guitar range, 12 for bass range) but using the MIDIMuRF Controller software you can create and download your own patterns over MIDI.

The RATE control varies the speed of the pattern generator while the PATTERN rotary switch selects the pattern presets.   The ENVELOPE control has a multiple function.  The envelope is technically a lag processor with adjustable rise (attack) and fall (release) rates.  The RATE control works in conjunction with the ENVELOPE control - the ENVELOPE control defines the rise and fall scale, while the RATE control defines the rise and fall constant.  The actual envelope rise and fall time is the product of scale and constant.  As the ENVELOPE control is rotated from 0 to 5, the fall factor increases more than the rise factor.  At the "5" setting both rise and fall factors are equal.  As the ENVELOPE control is rotated from 10 to 5, the rise factor increases more than the fall factor.  So the ENVELOPE control varies both the rise and fall factors, with enough variation to arrive at the desired effect.  This is a very clever way to reduce a panel full of knobs to just two controls (and keep costs down).

The LFO clock for the pattern generator can be controlled by the RATE control, by MIDI clock, or by tap tempo using a footswitch (or a clock) to the rear panel TAP/STEP jack.  The LFO rate LED changes color to tell you whether the clock is controlled by the knob (red) or by MIDI/Tap footswitch (green).  The TAP/STEP is a TRS jack and when you plug a footswitch in halfway, the footswitch will manually STEP through each pattern step - a convenient tool to audition steps in a user custom pattern.

What does a pattern generator sound like?!?  Hard to describe, but it can sound like nothing else out there.

MIX, RATE, and ENVELOPE jacks on the rear panel provide TRS voltage control of these parameters.  An LFO/SWEEP jack is dual purpose - with the pattern generator on, an external LFO or clock can be used to sync the pattern generator to external devices; with pattern generator off, a CV sweeps the center frequencies of the filters.  Stereo audio outputs spread the even numbered filters to one side and the odd numbered filters to the other side.

The MIDI implementation for this device is quite extensive.  There is too much to list here, suffice to say that just about any conceiveable MIDI control is implemented, including MIDI control of drive and output (!) and sysex.  Every control on the front panel can be controlled over MIDI - including the filter gain slidepots.  There are also some features inside that are accessable only by MIDI.

I like the MIDIMuRF as a fixed filter bank on the MIX IN/OUT jack of the Moog Voyager.  The MIX IN/OUT is used as an insert between the oscillator mixer output and the filters. With the MIDIMuRF patched into this jack, it is useful for varying the timbre of the oscillator(s) before they are filtered, which gets a bigger palette of sounds.  And because the MIDIMuRF has MIDI control, your sequencer can configure the filters for each Voyager patch.  Now that's power!

What does MuRF stand for?  Multiple Resonant Filter.  Too bad they didn't call it the Spectral Multiple Resonant Filter - SMuRF (I jest :-)


MF-108M Cluster Flux


Moog's latest Moogerfooger offering is the limited edition Cluster Flux which is a wonderful sounding MIDI controlled BBD-based flanger and chorus device.  Only 1000 of these units will be made due to the limited supply of BBD devices.

My previous beef involving the MF-104 is now resolved with this device - Yay!

I've seen plenty of flange/chorus processors but this box has features I have not seen anywhere else.  The usual TIME, LFO RATE, and LFO AMOUNT are there.  Not often seen is positive AND negative feedback (with facility for self-oscillation).  A very unique feature is the variety of LFO waveshapes - it offers sine, triangle, square, falling ramp, rising ramp, and... sample & hold?!?  This is the only flanger/chorus I've ever seen that offered sine or triangle modulation waveshapes, each of them resulting in a different effect - THANK YOU!  A rocker switch toggles the time delay RANGE between FLANGE (0.6ms to 10ms) and CHORUS (5ms to 50ms).  The LFO frequency range is 0.05hz (one cycle every 20 seconds) to 50hz, wide enough for most flange/chorus effects.

Like the MF-103 Phaser, this device generates a comb filter effect in FLANGE mode.  A major difference is the displacement of the frequencies of peaks/dips is different in a time delay processor as opposed to a phase shift processor.  FEEDBACK increases the sharpness and intensity of the peaks in FLANGE mode.  Positive feedback emphasizes all the harmonics of a fundamental frequency equal to the inverse of the delay time (even harmonics), while negative feedback generates a completely different comb filter effect in which odd harmonics are emphasized and the frequency response is shifted down one octave. If you don't comprehend that technical explanation, just trust that positive and negative feedback yields radically different effects.  In CHORUS mode FEEDBACK creates a detuned doubling effect, haas effect, or vibrato.  You can get a wide variety of chorus effects with variations of LFO rate, amount, delay time, and feedback.  Nice.

A new addition to the Moogerfooger format is the TAP TEMPO footswitch.  Interesting feature but with two problems: 1) how do you tap the footswitch fast enough for 10ms flange range and 2) Moog finally designed such a flexible LFO from so many requests, but neglected to include an LFO OUT on the rear panel (sigh).

MIX, LFO RATE, LFO AMT, TIME, and FEEDBACK jacks on the rear panel provide TRS voltage control of these parameters.  There is a FB INSERT jack for inserting a processor (such as a high pass filter) in the feedback path (tip=SEND, ring=RETURN).  Stereo audio outputs are provided, but they are simply out-of-phase outputs which will cancel when summed to mono.  An internal DIP switch configures the outputs in variations of dry/wet/mix and phase positions - factory default is right output & mix enabled, wet signal out-of-phase.

The MIDI implementation for this device is quite extensive.  The BBD clock is implemented in firmware which permits a lot of control possibilities over MIDI.  Every control on the front panel (except DRIVE) can be controlled over MIDI - you can save your flange/chorus settings in a MIDI string in your MIDI sequencer!   There are also some features inside that are accessable only by MIDI, such as delay time multiplier up to x8 and delay time portamento.

This device is really effective on my Fender Rhodes Silvertop piano and on guitar, especially through my Selmer Zodiac Twin Thirty amp.  The flanging can get pretty extreme and there are all kinds of chorus variations to be had.  Hard to get a bad sound from this thing.  It's a very flexible processor although a bit noisy - did they include a compander in this thing?  And be careful with LFO waveshapes that have stepped instantaneous edges (square, ramps, S&H) as the control feedthrough is a little leaky (translated: you'll hear a THUMP in the audio).  You can reduce this defect if you roll off enough bass in your mixer channel.  I think a smoothed S&H would had been more effective than stepped.



Click on the image below to see the innards of these devices.  Note the transition from through-hole components to modern SMT.  The Cluster Flux is really packed dense!



CP-251 Control Processor

The CP-251 is a utility box designed for processing and generating control voltages.  There are no audio processors in this device.  A commonly asked question is if a customer should get a CP-251 - it is a handy accessory for the Voyager, Phatty, and Taurus product line; but for Moogerfooger pedals it is useful to only those who are interested in experimenting with processing control voltages, have two or more Moogerfooger devices, and can grasp analog synthesizer concepts.

This toolbox includes a four input mixer with offset controls, lag processor with independent rise/fall times, white noise soure, two attenuators, LFO with triangle/square/S&H outputs, and a four-way multiple.  There are more features under this deceptively simple looking panel.

There are jacks with red nuts (later units replaced them with black nuts with a white ring label on the panel) that identify those that can accommodate a TRS passive or active control voltage pedal or external control source.  They are placed at strategic points.

The mixer is designed for control voltage IE it can process DC voltages.  Provided are two attenuation controls (inputs 3 and 4 are fixed with no attenuation), an offset control, and a master control.  OFFSET adds a DC offset to the final mix, useful for converting bipolar +/-(n)VAC signals (such as LFOs) to Moogerfooger-compatible 0-5VDC levels.  Input #3 bears a red nut which means it can accept a TRS passive control voltage pedal.  Complimentary +/- outputs provide a 180 degree out of phase signal on the (-) output.

The mixer CAN process audio up to 50Khz, but you must use caution so that DC offsets are not present on the output - with the wrong combination of equipment DC offset can cause damage.  Use at your own risk!

The LFO has a jack that can accept a TRS passive control pedal to remotely control the rate of the LFO, which has an LED to indicate the rate of 0.03hz (one cycle every 33 seconds) to 100hz.  The S&H works by "sampling" the noise source at the rate of the LFO, and "holds" the sampled voltage during that clock cycle.  The OUT1 jack is the stepped S&H while the OUT2 jack is the smoothed S&H.  The S&H has a couple of normalled jacks - input is normalled to noise source while trigger is normalled to LFO square.  The jacks allows you to use another independent clock source for the trigger, and another source for the input (such as pink or red noise) - and they both can accept a TRS control voltage pedal.  Quite flexible.  Since the smoothing operation of OUT2 is dependent on the LFO rate, you can use the rate control to vary the amount of "smoothing".

What use is this "lag processor"?  You use it to turn a square wave into a trapezoid even a triangle wave, or use it to "smooth" the stepped S&H. Some classic keyboard vibratos - such as the EMS "Putney" or Vox Continental - use a trapezoidal waveform.  Trapezoidal also makes interesting tremolo effects like those of guitar amps and the classic Rhodes piano stereo tremolo.  Trapezoidal can be used as a repetitive AR envelope.  The lag processor also functions as a glide processor for keyboard or sequencer pitch CVs.  Route the white noise through the lag processor to convert it to pink, red, or blue noise.

The first jack of the four-way multiple can accept a TRS passive control voltage pedal, which allows you to use one pedal to simultaneously control three devices.  The attenuator inputs also accept TRS pedals which allows you to reduce the sweep range of the pedal - handy if you're using a pedal to sweep the pitch of an oscillator.

I got one of the early CP-251s that used red nuts.  I liked the convention of using red nuts (it looks cool) but I can certainly understand the cost effective reasons behind using nuts of the same color.


VX-351 Voyager Output Breakout Box

The Voyager's rear panel has a comprehensive set of CV inputs, and the VX-351 is an option to bring the CV outputs to a breakout box.  A DB25 cable is used to connect the two together (the Voyager requires a conditioning accessory that needs to be installed inside the chassis, which is included with the VX-351).  Pretty much all the Voyager control sources - keyboard pitch/velocity/pressure/trigger, pitch bend wheel, mod wheel, LFO square and triangle, S&H stepped and smoothed, envelopes, noise source, touchpad x/y/z/gate, MOD pedals, wheel and pedal busses - are brought out to the panel for use with Moogerfooger devices or with external synthesizers or other audio processors with voltage control capability.  Also included are two attenuators and two sets of four-way multiples.


Rackmount accessories

Because of the professional audio quality of the Moogerfooger devices, I got the rackmount accessories so they could be racked with my other studio processors.  If I ever need to separate a device for floorpedal use, they are easy to remove.  There is also a rackmount accessory for the CP-251 and VX-351, with the advantage that when the VX-351 is connected to the Voyager, the CP-251 gets its power from the VX-351 so this eliminates a wall wart power supply.


april fools

Seems that the elves at Moog Music have a field day as April Fool's Day approaches.  Some notable examples of past April Fool's pranks are the MF-433, the MF-106TC, and the rare coveted MF/FM.  In a sly reference to John Cage's infamous 4'33'' composition, the MF-433 effectively silences the audio output for 4 minutes 33 seconds at the press of the footswitch.  The MF-106TC Time Compressor has the opposite function of analog delays in that is compresses the time of the input audio, allowing the performer to hear notes they haven't yet played.  The MF/FM lets you bring FM radio, complete with vintage analog tuner, to your fingertips for mangling radio audio.


contact info


* I hold animosity towards Eddie Van Halen because he falsely claimed that his sound was a result of using a variac on his guitar amplifer.  This is both untrue and dangerous because the variac will cause damage to the amplifier - even fire - to the copycat who doesn't know any better.  It is one thing to steer copycats off your trail, yet quite another to cause a fire with the potential of property loss or even death.  That is extremely irresponsible of Eddie to spread such a dangerous lie and I have lost all respect for him, regardless of his place in music history.