Line 6 M Series Modifications

(M5 modifications and repairs are no longer available. Unfortunately, it's proven to be an unreliable platform for changes.)

Audio Upgrade (AU): M9 $115 - M13 $135

Reduces background noise
Adds remarkable increase in fidelity and clarity
Effects are more profound and detailed
Clean signal is far more robust and clear
An analog master volume is added for fine level adjustment when effects are active or in DSP bypass mode 

Optional Internal Master Volume (INT-MV): $35

If you don't need  external access to the master output control added with the Audio Upgrade I can install this vital control on the inside of the case. You can adjust it with a small flat-head screwdriver through a small opening in the left-side-face of the case. The same potentiometer is mounted on a fabricated bracket in such a way that prevents it from being adjusted by accident or trauma to the case.  This may also set your mind at ease if you are concerned with accidentally bumping an external control while using it. (There example pictures of this in both M9 and M13 slideshows below.)

The Short of it:
The signal path between the input and output is upgraded and altered with audiophile grade passive and active components to maximize the efficiency of the stock CODEC. The analog to digital conversion process is fed a more pristine signal with extended headroom and added muscle from the power “rails”. Between the balanced CODEC output to the line level outputs, the signal path is streamlined to invigorate and protect the integrity of both affected and clean tones. Leaving the pedal in DSP bypass or “spillover” mode is no longer at the expense of your tone.

Replacement Switches (SW): M9 $99 - M13 $155

Replaces all  factory PCB mounted switches and plungers with new self-contained smooth action components. 


Remote Tap Jack (RT): M9 - M13 $50 ($30 when combined with other modifications)

Input tempo remotely with a normally open type switch (sold separately) or sync with other time based effect pedals that have an isolated remote tap jack via an MTPro. This does not change the factory function(s) of the regular TAP switch, holding the remote switch closed will access that switches secondary function. NOTE: this is not intended to be directly connected to the remote tap function of another pedal or simple "multitap" pedals that share the same switch contacts or ground at the case, doing so will expose either device to incompatible voltages/logic grounds and eventually result in irreparable damage. It will work with the isolated outputs of switch/relay based multi-sync devices, like any version of the MTPro, or those from Tapestry Audio and Disaster Area Designs.

Dedicated Looper Toggle Switch for M9 (LP): $85

Let's you press one time without hold to access looper mode without changing the nature of the TAP switch. Two different techniques:

1) No wait, instant Looper Mode. Caveat: involves tapping into the incoming MIDI messages and sending commands for the looper to toggle instantly. The only drawback is the possibility of the corruption of one of the incoming MIDI messages (like one of the 24 clock ticks per beat when using MIDI clock from an external source). You may or may not notice this, but know it's a possibility.

2) Auto-Hold. The "let me do that for you without MIDI" version. Caveat: This simply simulates you holding down the switch yourself and will take the same time to activate, just you only have to press the new switch once.

M9 Dedicated Scene Select Footswitch (SCN):
$45 ($30 when combined with additional M9 modifications )

Access the scene select screen on the M9. This helps you avoid the awkwardness of missing the two switch combination on stock units. Once activated the selection process is the same as before.

Expression Switches for M9 & M13
$45, 2 x $80 (latching with LED)
$30, 2 x $45 (momentary without LED)
$65 (1 x latching & 1 x momentary )

Simulates an expression pedal in “heel down” or “toe down” positions. You may already be familiar with this feature which enables two different settings (same model(s) but different parameters) per preset enabling you to morph between settings with the expression pedal. By following the related instructions found on page 3.3 of the Line6 “M9 Advanced Guide” and pages 2.2,3.3 of "M13 Advanced Guide” you can set up these two unique combinations per preset then have instant access to both with this new switch. The default location for the first switch is EXP 1, however you can specify which you prefer especially when ordering a combination of momentary and latching. 

*When using an external expression pedal, the mod is bypassed and the factory expression feature functions as normal.

"Where do you install these extra switches?"

For the M9: Expression Switches are installed on the top deck above FX1B and FX2B. When adding two Expression Switches AND a Scene Select switch, the later is installed just to the left-center of the main display. 

If three new switches for the M9 are combined with the Audio Upgrade, the new total output control will need to be located elsewhere. For the M9 this is usually on the back face just between the stereo I/O jacks, or for a $20 upcharge, mounted to a fabricated bracket on the inside of the case that is accessible from the left-side-face of the enclosure. (Examples can be seen in the M9 slideshow above.)

For the M13: Expression Switches are installed on the far right of the top deck just to the right of FX Unit 4 control knobs. When adding two Expression Switches, the default locations are one above-center the "M13 Stombox Modeler" screen print and one below-center. Single switches are installed below-center. 

If two new expression switches for the M13 are combined with the Audio Upgrade, the new total output control will need to be located elsewhere. This is usually on the back face close to the AC power input and power cord tension relief "T". For a $15 upcharge, this output control can be mounted to a fabricated bracket on the inside of the case. This internal adjustment is accessed with a small flat head screwdriver through a hole in the left side of the case. This enables you to "set and forget" the output level and eliminate the chance of accidentally changing a control mounted to the outside of the case. (Examples can be seen in the M13 slideshow below.)

Latching switch* - includes an indicator LED that is mounted near each switch respectively.

Momentary switch* -  smooth quiet travel that allows you to instantly toggle between expression settings. Pressed down = "Toe Down"  and "Heel Down" on release. Pulse expression settings for interesting sounds,  a two octave up or down setting works fantastic with this mod! (Does not include led indicators.)

(Custom Options: If you'd like your switch mounted in a different location email me with your idea and we'll explore the possibilities; The “Expression Switch” features can be accomplish with a small external switch and red indicator LED.)


M Series Repairs

Switches aside, the M series from Line 6 is a very robust platform, and most any component failure can be repaired. Whether you have a loss of audio, intermittent signal, broken knob shafts, broken AC jack, failure to power up etc. I can fix it. Simple knob replacements to more complicated repairs (replacing CODEC) range from $40-$80 plus return shipping. The fix related to M9's with a serial number including S5934 is $75 plus return shipping. 

If one of the normal upgrades actually corrects your problem there's no additional charge. If having an upgrade in addition to repair work you may be eligible for a discount towards the repair labor.

Why is it necessary to replace the stock switches?

  • Another great pedal series from Line 6! But design (think DL4) again may have been a casualty to bottom line leaving the pro player wanting a bit more.

  • Replaces all stock surface-mount switches and actuators with smooth action robust self-contained momentary switches for years of professional use.

  • If you often need to input tempo with the stock switch it will fail sooner or later depending on your angle of attack. A failing actuator to surface mounted tactile switch will typically fail in the following progression:

    • As vague as this sounds, initially they’ll seem stiff every now and then

    • The time it takes the pedal to recognize your input will begin to seem “off” (especially on the tap switch)

    • It becomes increasingly difficult to lock in the desired BPM as a the duration of useable tempo’s interval decreases before it’s necessary to re-tap for a musical sync to rhythm.

    • The switch will completely lock up but will work again after forcefully striking it with your foot, beer bottle, or wah-pedal (none of which are recommended)

    • After the previous resourceful attempts to free the switch help less and less the switch no longer functions at all.

    • Influenced by an overwhelming feeling that “this used to fix it”, too much force is applied to the switch hastening its destruction.

    • You pray that some poor sucker on E-Bay will never notice the difference, or you rant on a gear forum until you feel better.

  • Life is short, don't let a bean counter keep you from enjoying your favorite pedals.

What clients are saying about the changes:

Thanks for working on my M9.  It seems better than ever so far!  I’m glad I decided to do the audio upgrade as well as the two expression switches.  Thanks for your patience and quick turn around!

Got the M9 back today.  The switches feel great, and I’m looking forward to my looper not turning itself on and off during shows. :)  I’m really digging the audio upgrade, too.  I have to readjust the parameters of pretty much every patch I dialed in, and they’re coming out fantastic. Definitely a worthwhile upgrade.  The master volume control seems to be at unity at noon or just above…it varies with each patch right now.  I can level them out, though.  

Thanks so much for the great work and speedy service! I’ll be recommending you to everyone I know with an M-series pedal. 
Justin Ostrander

The M9 has spent some time with me and sounds absolutely fantastic!! Thank you so so much for everything. What a journey we've been on with this little monster. Your customer service is beyond explanation, Jack. Impeccable. And you can use that on your website.
All the best to you, Jack. Thank you so very much!!!
Frank Cifarelli

Thanks for your awesome work! This M13 sounds incredible! The big thing for me is the pitch shifting patches track so much better. Can't wait to get my M9 done! Thanks again,

I must say that I am more than pleased with the Mod’s.  The whole overdrive, distortion sounds were pretty much unusable to my ear prior to the mod.  Based on YouTube and reviews (and my experience with mods to DL stuff), I knew the time-based stuff would improve but I don’t know what you did to the other stuff but it all just sounds SO MUCH better.  So much so that I’m likely going to get a second one or an M13 and have you mod it!!Thanks, again!!

Please Note: Line 6 is an outstanding company that has consistently produced stellar products designed by some of the most brilliant minds in the industry. As many of these innovators moved on to start their own companies they continue to raise the bar on the standards by which all others are compared to.

Unfortunately, as for any company with mass production, maintaining healthy profit margins often requires choosing parts that fit within an acceptable margin of error/failure/accuracy/price which are most efficient/profitable to use in the process of manufacturing.

Purchasing departments of large companies get a list of parts with quantities, values, ratings and sometimes exact tolerances, for mission critical sections of circuit systems. Otherwise, the common standards per component type are acceptable. The higher the tolerance, the more expensive.

Somewhere in here a balance must be reached.  I imagine a negotiation via emails and/or unnecessary memos and meetings between engineering/design and purchasing/manufacturing occurs with phrases like "can we get away with ___ (specification)?", "Will a __ work instead of what's spec'd?", "What's the margin we're really working with here, can we use a ___?"

Brand new and out of the box these pedals are remarkable and extremely useful. The M Series is unrivaled in power and utility for the price.  These modifications replace key parts with superior parts that otherwise would have driven the price of these units out of reach for most.