Music Thing Modular Spring Reverb Mkii – Panel / PCB Set & Phono Sockets

From: £26.50 (Excl. VAT)

You can use both a Spring Tank and a Digital Brick with one Spring Reverb Module, to use a Tank and Brick at the same time you’ll need the Spring Reverb Expander

Note: this is Panel/PCB Set only which includes 2 x PCB Mount Phono sockets.

The Vactrol required is no longer available from Thonk so must be sourced elsewhere.

Choose panel type/colour

Out of Stock


The Belton/Accutronics Spring Tank and Digital Brick is sometimes available as an extra option to buy from us, discussion of Brick and Tank suppliers here.

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.
  • New improved circuit

Buy the Expander here –

Thonk Build Document –

This Panel/PCB Set also includes 2 x PCB Mount Phono sockets. It does not include the vactrol required.


More Features

  • Works with a variety of spring reverb tanks (not included), 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). Vactrols are no longer available from Thonk so must be sourced elsewhere.
  • 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 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.

Additional information

HP Size

Choose panel type/colour

Weight N/A
Panel Type

Aluminium Frontpanel, Black Aluminium Frontpanel

HP Size