PLEASE NOTE: THIS MODIFICATION IS ALSO AVAILABLE FOR THE
LINE 6 DL4 DELAY MODELER

The Line 6 FM4 Filter Modeler is a multi-effect unit from Line 6′s popular Modeler range. In this pedal, Line 6 took many famous filter effects, vintage synthesizers and vocoders as inspiration to inspire guitarists to look outside-of-the-box. Most of the models in this stompbox are pure unobtanium – you’d be hard pressed to see one on eBay, let alone have one of your own. The FM4 neatly packages sixteen models, with some sounds instantly recalling musical heroes such as Zappa, Fripp and Frampton. Examples of some of the inspired models are the Mutron III Filter, Oberheim Voltage Controlled Filter, Z-Vex Seek Wah, Korg x-911 Guitar Synth and waveforms from vintage synths such as the Prophet 600 to the legendary Arp Explorer.

This purple beast has four footswitches that allow you to instantly recall four saved presets. The five control parameters allow you to select the Frequency, Q, Speed, Mode/Pitch and Mix of each filter/synth setting. Expression Pedal control allows you to morph between two different saved settings in the one preset. For example, heel down of the expression pedal can be saved for 50% Speed and 50% Mix and toe down can be saved for 100% Speed and 100% Mix. This lets you morph between these two settings and stop at any parameter along the way – useful for keeping in time with a fluctuating rhythm section.

The Line 6 Modeler range has gained a bad reputation as unreliable due to some design limitations. Firstly, the switches used are not on/off switches, but spring actuators that “click” a surface mount switch on and off. These switches feel unsturdy and are normally the first things to break. Secondly, many users noticed a volume drop when activating the pedal. The output level was affected by component values in the buffer circuit with varied levels of “drop” in different pedals.

The DIY community was pleased when pedal designer Jeorge Tripps (Way Huge, Line 6, Dunlop) released information in tackling these initial limitations, it led to a number of pedal makers and modders to offering their services to improve the Line 6 Modelers. Robert Keeley offers a hi-fi mod involving the replacement of IC chips for Burr Brown’s and some part-time modders (DRASP at Harmony Central Effects Forum) improving on the flexibility of the pedal. After intensive experimenting successes (and failures), cubisteffects now offers a number of modifications to the Line 6 Modelers.

As you can see in these pictures on this page, I have custom sprayed the once-purple pedal to a Barbie Pink. This is not the colour of the original !

cubisteffects offers not only a modification to rectify the initial design flaws but also has a number of modifications that can improve the flexibility of the unit, and some that push the pedal to become a new experimental tool.

STANDARD MOD

The Standard Modification involves three changes;

1. SWITCHES – The spring actuators are removed and momentary SPST “soft-touch” switches are installed. These switches are screwed to the pedal chassis and are wired to the place of the switch providing thousands of clicks without touching the PCB.
2. VOLUME DROP – Selected capacitors and resistors are removed and, if required, replaced with metal film components.
3. LEDs – The four red LEDs are replaced with superbright, waterclear LEDs of your choice.

EXPRESSION MOD

A rugged 24mm Alpha pot is placed on either side of your preference. This allows you to use the Expression Pedal controls without having an expression pedal take up pedalboard real estate. The modification enables you to save and morph between two settings per preset by rolling your foot over the knob. Settings are saved as per the Line 6 instruction manual.

FEEDBACK MOD

This modification involves re-routing the output of the Modeler back into the input, and the new output selected by a switch on the top of the chassis. This is a feedback loop, and causes spontaneous bursts of noise, squeals, oscillations, drones – all depending on the setting selected. This modification is definitely for the more adventurous musician, but with every effect, the feedback can be used subtly. Most times the feedback can be deafening so it must be used with caution. However, I have installed a small knob that sits aside the switch allowing you to control the amount, pitch, speed of the feedback. A superbright, waterclear LED indicates whether the feedback loop is on or off.

The cool thing with this modification is that the FM4 becomes a stand-alone noisemaker or “synth” as a loose term. I found it best run through a mixer to control its levels more accurately and left as a table-top unit. Alternatively, if on your pedal board, running your guitar through it will produce a background oscillation (especially in the Synth models) similar to the Z-Vex Fuzz Factory.

Other modifications offered are:

TWIN PRESET MODIFICATION

This preset lets you save two different settings per preset as per the Expression Mod. However unlike the Expression Mod, the two settings are selected via a stomp switch. This allows you to instantly switch between two settings without the need for an expression pedal. The selected preset is indicated by a superbright, waterclear LED.

DISTORTION CIRCUIT BENDS

WARNING: Volatile and extreme modification. Not for the faint-hearted.
This mod involves two circuit bends that work around the same principle as the Feedback Mod but are much more pronounced and distorted. Crackling, white noise, fuzzed insanity can all be activated via two independent toggle switches with a knob controlling the output volume for both. Superbright, waterclear LEDs indicate whether bend is on or off (but you can clearly hear them if they are on!)

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The Line 6 DL4 Delay Modeler has become a staple on many guitarist’s pedalboards – from professionals to bedroom rockers. It packs 15 different delays into a four stomp box – enabling you to have anything from Floydish tape echos one second to reverse Hendrix solos the next. Expression Pedal control allows you to morph between two different saved settings in the one preset. For example, heel down of the expression pedal can be saved for 50% Repeats and 50% Mix and toe down can be saved for 100% Repeats and 100% Mix. This lets you ride the pedal into oscillation and back it off when it starts to run away.  The three presets give you your favourite sounds one-click away while the fourth switch is a tap tempo control. But perhaps the hidden gem in this versatile pedal is the excellent 14-second looper which lets you record a phrase and manipulate it via a one-shot, reverse, half-time or double-time speeds.

Line 6 also offers more Modelers in this four-button stompbox format: The MM4 is a Modulation Modeler that contains classic emulations of phasers, flangers, tremolos etc. The FM4 is a Filter Modeler and changes the guitar into a vintage synth with a step of a switch. A Distortion Modeler, the DM4, recreates many of the hard-to attain fuzzes, overdrives and distortions. The discontinued AM4, Amplifier Modeler, can also be found on eBay from time to time.

As much loved as the pedal is, it has gained a bad reputation as unreliable due to some design limitations. Firstly, the switches used are not on/off switches, but spring actuators that “click” a surface mount switch on and off. These switches feel unsturdy and are normally the first things to break. Secondly, many users noticed a volume drop when activating the pedal. The output level was affected by component values in the buffer circuit with varied levels of “drop” in different pedals.

The DIY community was pleased when pedal designer Jeorge Tripps (Way Huge, Line 6, Dunlop) released information in tackling these initial limitations, it led to a number of pedal makers and modders to offering their services to improve the Line 6 Modelers. Robert Keeley offers a hi-fi mod involving the replacement of IC chips for Burr Brown’s and some part-time modders (DRASP at Harmony Central Effects Forum) improving on the flexibility of the pedal. After intensive experimenting successes (and failures), cubisteffects now offers a number of modifications to the Line 6 Modelers.

cubisteffects offers not only a modification to rectify the initial design flaws but also has a number of modifications that can improve the flexibility of the unit, and some that push the pedal to become a new experimental tool.

STANDARD MOD

The Standard Modification involves three changes;

1. SWITCHES - The spring actuators are removed and momentary SPST “soft-touch” switches are installed. These switches are screwed to the pedal chassis and are wired to the place of the switch providing thousands of clicks without touching the PCB.
2. VOLUME DROP – Selected capacitors and resistors are removed and, if required, replaced with metal film components.
3. LEDs – The four red LEDs are replaced with superbright, waterclear LEDs of your choice.

EXPRESSION MOD

A rugged 24mm Alpha pot is placed on the bottom right of the pedal, adjacent to the tap tempo switch. This allows you to use the Expression Pedal controls without having an expression pedal take up pedalboard real estate. The modification enables you to save and morph between two settings per preset by rolling your foot over the knob. Settings are saved as per the Line 6 instruction manual. The knob can be put on either side of the pedal.

FEEDBACK MOD

This modification involves re-routing the output of the Modeler back into the input, and the new output selected by a switch on the top of the chassis. This is a feedback loop, and causes spontaneous bursts of noise, squeals, oscillations, drones – all depending on the setting selected. This modification is definitely for the more adventurous musician, but with every effect, the feedback can be used subtly. Most times the feedback can be deafeningly loud, so I have installed a separate BLEND knob to dial in the volume you wish.st be used with caution. The second knob controls the INTENSITY of the feedback allowing control of the amount, pitch, speed of the feedback depending on the delay setting.. A superbright, waterclear LED indicates whether the feedback loop is on or off.

Below is a demo:

Other modifications offered are:

TWIN PRESET MODIFICATION

This preset lets you save two different settings per preset as per the Expression Mod. However unlike the Expression Mod, the two settings are selected via a stomp switch. This allows you to instantly switch between two settings without the need for an expression pedal. The selected preset is indicated by a superbright, waterclear LED.

DISTORTION CIRCUIT BENDS – NO LONGER OFFERED

WARNING: Volatile and extreme modification. Not for the faint-hearted.
This mod involves two circuit bends that work around the same principle as the Feedback Mod but are much more pronounced and distorted. Crackling, white noise, fuzzed loops can all be activated via two independent toggle switches with a knob controlling the output volume for both. Superbright, waterclear LEDs indicate whether bend is on or off (but you can clearly hear them if they are on!)

C.