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Spring Reverb MK2 | Music Thing Modular

Spring Reverb MK2 | Music Thing Modular


The Music Thing Spring Reverb MK2 is a flexible, easy-to-build voltage controlled DIY mono spring reverb module.

This is a full kit set in the Eurorack format. These are Thonk created kits - now available from within the US!

NOTE: These ship with the aluminum panels, and without the Accutronics brick and/or a spring tank - those need to be seperately sourced

Availability:Out of stock

This is a full kit that includes everything you need to build a 6hp Eurorack module, you just need to provide the spring tank or digital brick. The Music Thing Spring Reverb Mkii is a flexible, easy-to-build voltage controlled DIY mono spring reverb module. Traditional guitar reverbs are tuned to the sound of the guitar and the amplifier it is played through. This circuit is different; designed to be relatively clean and high-fi, with a lot of bass response. Use real spring reverb tanks, or solid state reverb bricks.

New Features of the Spring Reverb Mkii include:

  • Internal Feedback control with CV input, dedicated attenuverter and with invert switch for maximum feedbackiness
  • Wet out and feedback in sockets for more flexible patching
  • 3HP Expander – allows for instant switching between reverb brick and spring tank – or set a blend between the two
  • Expander also allows for front panel send and return to spring tank. (Sold Separately)
  • New improved circuit

More Features

  • Works with a variety of spring reverb tanks (optional), or with the Accutronics BTDR-2 reverb ‘brick’ designed by Brian Neunaber (optional)
  • Vactrol (VTL5C3) crossfade between dry and wet (vactrol circuits are variable in their ability to go completely 100% wet, like the Make Noise Echophon for example)
  • Tilt EQ on the reverb send to tune the voice of the reverb
  • X-Fade input so the module can also be used as a standalone vactrol crossfader (crossfade demo)
  • Feedback circuit with positive and negative phase
  • Attenuverter on the crossfade CV input
  • 6hp wide (NB: If using the brick, mounted horizontally, the brick extends 5mm over the PCB to the left of the module, around 25mm back from the front panel, so mount the reverb next to a shallow module)
  • Expander with Front panel mount Phono sockets & Crossfade between reverb types (Sold Separately).

Expander info: 

The Music Thing Spring Reverb Expander is designed to connect to the Music Thing Modular Spring Reverb Mkii. The expander adds the ability to blend the reverb tank and brick outputs and manually crossfade between the two. This module also adds the option to connect to your reverb tank from the front panel rather than the back PCB of the main Spring Reverb module. This expander is passive so doesn’t require a power cable.


Note: This expander is only compatible with the MTM Spring Reverb Mkii – It will not work with older revisions.




  • Front panel Send & Return sockets to Reverb Tank
  • Set blend level between Spring Tank and Brick Outputs
  • 3HP Front Panel – In Silver Aluminium


Additional Information
More Information
Brand Music Thing Modular
Additional Resources Spring Reverb MK2 Build Guide Spring Reverb MK2 Expander Build Guide

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