Moog MF-105 MuRF
Eight resonant bandpass filters, twelve patterns, and a drive stage that turns a clean guitar into something that sounds like it's been dragged through a modular rack.
Overview
The MuRF — Multiple Response Filter Array — is the odd one out in the Moogerfooger line, and that's precisely why collectors keep coming back to it. Where most stompboxes chase a vintage effect or a slightly tweaked variation on one, the MF-105 does something genuinely different: it puts eight resonant bandpass filters in a row, each with its own level slider and its center frequency printed right there on the panel, then animates them with a pattern generator. Electronic Musician (April 2005) described it as offering "something unique" among stompboxes, and the review's 4.5-out-of-5 overall rating suggests the magazine found the execution as interesting as the concept.
The filter complement is only the beginning. The Animation section — a Bank switch plus Pattern, Envelope, and Rate knobs — is what turns a static filter bank into a rhythmic processor. The Pattern knob selects from 12 patterns that trigger envelopes for the eight filters, and the Rate knob sets how fast those patterns run. The Bank switch toggles between two filter banks for a total of 24 available patterns; Bank B activates an LFO that subtly modulates filter frequencies, while Bank A patterns are unmodulated. The Envelope knob is the sleeper control — Electronic Musician noted that settings from 1 to 3 close the envelope quickly for percussive, staccato sounds, settings between 3 and 7 blur the pattern steps into something more phaser-like, and settings above 7 reverse the envelopes sent to the filters, producing staccato effects that sound backward. That's a lot of tonal territory from one knob.
The signal path is straightforward but thoughtfully built. The input accepts both instrument and line-level signals, and a Drive knob adjusts the input response while an Output knob sets output level. The Drive stage is more forgiving than the LED color-coding suggests — Electronic Musician found that when the signal hits the red zone it isn't necessarily a warning to back off, and that pushing it added nice overdriven warmth to the creamy-sounding filters. Bypass is hard bypass, often called true bypass on guitar pedals: when engaged, the audio input passes directly to the output with no tone-altering components in the signal path. The output is mono, which the review flagged as a limitation for outboard studio use — stereo outputs would have made the MuRF more useful as a processor for prerecorded material, though as a live guitar pedal the mono output was never an issue.
Real-time control is where the Moogerfooger lineage shows through. The MF-105 offers control inputs for Rate, Mix, Envelope, and LFO/Sweep, accommodating expression pedals, synths with control-voltage outputs, or MIDI-to-CV converters. A control input is the only way to control LFO/Sweep, which sweeps the filters' center frequencies by ±15 percent in Bank A patterns and changes the LFO rates in Bank B patterns. One quirk worth knowing: when using a control input, the control range is centered around the current position of the relevant knob, and the controller's range can never exceed the range of the knob. Set the Rate knob at 5 and an EP-1 expression pedal gets the full 0-to-10 range; set it at 3 and the pedal's range is only 0 to 8. The MuRF was also the first Moogerfooger to offer a tempo-tap option using a momentary switch such as Moog's FS-1, with the unit interpreting the time between taps as half the tempo — tap quarter notes and the resulting rate lands in eighth notes. When Tap Tempo is in use, the Rate knob is ignored, though adjusting the Rate knob afterward supersedes the tapped tempo.
One early production issue is worth flagging for anyone shopping used units. Electronic Musician discovered that using a continuous controller to sweep the MuRF's LFO resulted in clicking artifacts at extreme values, and Moog said the problem occurred with no more than 30 of the first units shipped and had been fixed. That's a small window, but it's the kind of detail that separates a careful listing from a hopeful one.
In practice, the MF-105 rewards experimentation more than it rewards a single setting. Electronic Musician used it both as a live guitar pedal and as an outboard processor for prerecorded synthesizer tracks, and found that by adjusting the filter volume sliders and Animation controls it was possible to create mind-bending step-sequencer and arpeggiated filter effects. The review's verdict was warm but honest: the MuRF is definitely on the expensive side of boutique effects boxes, and the mono output is a real limitation for studio work, but for anyone looking for an unusual and creative filter bank it won't disappoint.
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