Mimir's Well

FV-1 DSP Pedal Platform


What are the controls? What does it look like?
  1. Parameter Controls: the 3 white knobs control different parameters depending on which patch you're running
  2. Patch Name
  3. Patch Selection: choose between patches in the selected bank (3 banks of 23 patches)
  4. Volume
  5. 3-way Bank Selection: select between the built-in bank of patches, and 2 banks of custom patches
  6. Wet/Dry Mix
  7. True Bypass
  8. Top Mounted Jacks
  9. Power: 9V, center negative power supply required (not included)
walkthrough of Mimir's Well

Video Demo


23 Pedals in One Enclosure

Mimir's Well is a very limited batch of expertly handcrafted guitar pedals powered by the extremely popular FV-1 DSP (digital signal processor). It allows you to run audio processing patches that create amazing reverb, delay, pitch, and other effects.

NOT a Cheap Multi-FX

This is the same chip that powers pedals such as the EQD Rainbow Machine and Dispatch Master, Subdecay Super Spring Theory, EHX Holy Stain, Catalinbread Topanga, Walrus Arp 87 and Fathom, Black Hole Symmetry, Fuchs Plush Good Verbrations, and tons more. Just like those, it uses all of its hardware to run a single patch at a time. Unlike those, however, it also holds 23 patches you can switch between.

Make It Yours

You customize your pedal by choosing from 163+ available patches designed by professional audio engineers and amazing members of the DIY pedal community.

Who's This For?

You will be delighted with this pedal if you want...

  • ...to easily (and cheaply!) find one or two new pedals you'll really, really love
    • Most of us don't actually need the dozens of new pedals (patches) you can get with Mimir's Well, but it lets you avoid months of buying (then going through the hassle of selling) dozens of single-patch pedals in search for that perfect sound
  • ...to try every nuanced variation of a specific effect type, and dial in to perfection
    • Find a perfect tape echo: Single or dual head? Or triple tap? With or without ping pong?
  • ...to endlessly experiment with dozens of different effects
    • Audition as many as you want for $1/patch
  • ...to learn to write your own DSP programs
Buy Now

Mimir's Horn, a more affordable version without the screen is also available. Shop Mimir's Horn


What sounds can you make?

Choose 16+ Patches

Visit the bank builder to see a list of many of the available custom patches. These patches are created by professional audio DSP engineers, as well as members of the DIY pedal community.

You can choose 16 custom patches (2 banks of 8) to preload into your pedal, and you can also buy more for $1 each, and swap banks.

Visit Patch List

Built-In Patches

In addition to the custom patches you select, the pedal comes with 7 excellent built-in patches.

Name Knob 1 Knob 2 Knob 3
Chorus + Reverb Reverb mix Rate Chorus mix
Flanger + Reverb Reverb mix Rate Flanger mix
Tremolo + Reverb Reverb mix Rate Tremolo mix
Pitch shift Pitch +/- 4 semitones - -
Pitch Echo Pitch Delay Echo mix
Reverb 1 Time High filter Low filter
Reverb 2 Time High filter Low filter

Let's hear them!

Check out the demo video on YouTube, or in the Walkthrough section above to hear a variety of patches.

Like other FV-1 based pedals, this pedal's sound comes entirely from the patch running on it. There are 163+ patches so it's simply not possible for me to demo all of these. (especially since this is a very small batch of handmade pedals, not an ongoing production run... Plus I don't have a decent video rig)

To hear the level of quality you can expect from this pedal and its programs, check out some of the other pedals in the wild that share nearly identical circuitry:

  • EQD Dispatch Master
  • Subdecay Super Spring Theory
  • EHX Holy Stain
  • Catalinbread Topanga
  • Walrus Arp 87
  • Walrus Fathom
  • Black Hole Symmetry
  • Fuchs Plush Good Verbrations

I guarantee you will find at least a few you love, or you can return for a refund within 7 days. Plus, you can try tons of extra patches for only $1 each, then when you narrow it down to the few you love, consolidate them onto 1 or 2 banks.

3 Versions


Mimir's Horn

Get the exact same, fantastic sounds as Mimir's Well, but in a smaller package with a fewer bells and whistles.

  • 8 custom patches in a single bank
  • Additional patches for only $1 each (requires swapping internal banks)
  • Customize your labels
  • Choose from a variety of graphic options


Mimir's Well

This is the most popular, flagship pedal, described throughout this page.


Mimir's Well: Custom Package

This deluxe edition is the same great Mimir's Well pedal described throughout this page, but gives you the flexibility to make it 100% your own.

  • Customize graphics
  • Customize labels
  • Choose knobs and colors
  • Free t-shirt

Perfect for...

The Connoisseur

Your meticulously selected, killer effects

We can help you sort through hundreds of awesome pedal programs and find the precious few you'll take to your grave...

The Specialist

Deep dive into one effect

Want every possible variation of a Shimmer Reverb, or half a dozen Ping Pong delays? You'll have plenty of options to dial in the perfect sound...

The Tinkerer

Endlessly experiment

Want to explore dozens or hundreds of pedals? Maybe even write your own?! This is the platform for you...

Free and Open Source

For a very motivated DIY'er, I've posted everything you need to build this pedal on github.

Or if you already own a pre-built pedal, this github repository is also great if you want to customize the display code (different colors? different fonts? completely redesign the screen?)

It also has the code and tools to make your own EEPROMs.

I also sell PCBs and kits that can take away some of the trickier parts of this build:

  • $89 Partial kit with pre-soldered surface mount DSP chip, pre-programmed display microcontroller, and more
  • $12 PCB only


Check out the demo video on YouTube, or in the Walkthrough section above to hear a variety of patches.

If you're looking to hear all of the patches, that's simply not feasible. See more details in the "PATCHES" section above for an explanation. If you're worried about the risk of not liking it, we'll mitigate that risk in 2 key ways:

  1. Although it's not practical for me to give demos of 163+ patches, I do guarantee you'll find at least a couple you love, or you can simply send it back for a refund within 7 days.
  2. You can order as many banks as you like (effectively at-cost), and swap them out until you find what you love. Then email me and I can send you a consolidated pair of banks.

No. Not in the way you're probably imagining. You don't pick and choose multiple effects to chain or layer like you would with a modeling amp, or a little pod unit. Those are a jack of all trades, and master of none.

The patches written for this pedal use low-level DSP code that modify the audio signal in complex mathematical ways. Each is written very specifically for the desired effect, and the result is a single "pedal". It requires 100% of the hardware and DSP's capabilities to run, so you can only use a single patch at a time.

A patch is not a collection of approximated (or modeled) pedals; it's a single pedal, precisely.

Since this is a high-quality DSP, and not a general-purpose modeler, you can only run a single patch at a time.

If you find more than one patch you love, and want to run them both (and I suspect you will!), you can obviously buy another Mimir's Well pedal. This is a limited-time small batch of pedals, though, and they may sell out.

I'm offering an ongoing made-to-order smaller version of this pedal. For $219 (and occasionally less) you can get the same great sounds in a smaller package, with a single custom bank (8 patches), and no screen.

Because these are made-to-order, that also means you can choose custom colors, labels, and pick from a variety of graphics to really make it your own.

More questions?

If you have other questions I didn't address on this page, please email me: mark@mas-effects.com

Swapping Banks

If you want to try more than 23 patches, you'll need to swap out the bank chips in the pedal.

This isn't a routine part of using the pedal; It's only really for auditioning a bunch of patches to find your perfect sounds.

It's pretty straightforward:

  • Banks are pairs of color-coded EEPROM chips. The chips are labeled with colored numbers/letters, and the sockets are color-coded too.
  • Unscrew the back plate
  • Pull out a pair of corresponding blue and yellow chips
  • Push in the new one
  • It's totally okay, and even recommended to leave the back plate off the pedal until you're done auditioning patches

Once you've tried out everything you're interested in, come back and we'll consolidate your favorites onto 1 or 2 banks so you never have to swap again.