elliptic

I did a bunch of testing, documented elsewhere, but the underlying cause appears to be expression pedal assignments and some combinations of effects. I found that just completely removing the expression pedal assignments makes the problem go away, even after you put the expression pedal assignments back again. Bit of a pain to go back and set up all your expression settings again, but at least the tuner now works again. Fingers crossed it doesn't come back.

So I did a bunch of testing and here's what I've found. I backed up my settings and loaded them on to the 2nd M13. It still worked fine, so it seemed to be a fault with the 1st M13. More testing revealed that it was only on some scenes, and it was only if effect 1A was on. I mucked around and found that it depended on what effect was in 1A. For example Volume Pedal, Red Com and Blue Comp all work fine, but Boost Comp and Facial Fuzz don't. I finally discovered that it has to do with how your expression pedals are assigned. I removed all assignments from the expression pedals, and the problem has gone, even after I put the expression pedal assignments back. It seems like the software gets itself confused, but removing the expression pedal assignments snaps it out of it.

You can back up all your settings via midi and restore them later. I'm having the same problem, I had the switches replaced with heavy duty ones and it made no difference, and in any case the tap button works just fine, it's only the tuner, and it only doesn't work on some scenes, so I'm pretty sure it's a software problem.

I have two M13s, on one of them the tuner works fine (although the box has other issues), but on the other the tuner button only works for some scenes. I thought it was the switch but I've now had all the switches replaced with heavy duty ones. In any case the tap function always works as expected, it's only with some scenes that the tuner button just doesn't work i.e. doesn't switch into tuner mode.

Guitar->M13->amp, although I tried going in to the fx loop return and the noise is there too. If you record using the looper the noise gets recorded, regardless of the pre/post setting, so it really does seem to be in the input stage. Noise gate is off, but turning it on doesn't make any difference.

Here's an audio file so you can hear it as I don't think I described it very well. If I have the only M13 on Earth that has this problem I will be very surprised. The first bit starts off with no effects and just switches between true bypass and dsp bypass. The next bit is straight (true bypass) and then with a chorus. The problem is the same regardless of what effects are in the chain.

I found it to be pretty finnicky about the midi interface. It wouldn't work at all with one of mine, worked fine with a different interface.

I'm having a problem with my M13 where there is a hissing, sort of swelling white noise surf-ish sound whenever the input level is at 10 on the guitar and the notes are roughly between low E and an octave above. It happens with all my guitars - a '72 Telecaster, a '75 Les Paul Deluxe, a '69 Mustang etc - so it's not that the guitar has a particularly hot output. It's a surf kind of swell of noise that starts just after the note is struck and swells and fades over about a second or two, with the duration being directly related to the volume i.e. it gets shorter as you turn the volume down or pick softly or mute the note. I don't think it's clipping as it doesn't start right with the note attack, and the intensity doesn't change with the volume changing (it actually swells at the start), just the duration. The underlying note isn't distorted, there's just a background noise. I've reset to factory settings, and then I re-installed the firmware (2.04) entirely, made no difference. If I set to true bypass and switch off all effects it disappears entirely and everything is clean. It does remind me of the surf kind of noise you used to get with early chorus pedals except that it doesn't matter what type of effect it is, even just a single eq or reverb has exactly the same problem, and it happens when there is no effect switched on when set to dsp bypass. I've never come across a problem like this.