There have been 5 versions of the mono Wet Mono Reverb:

  • version 1 (model year 2009, brushed aluminum with blue & silver overlay)
  • version 2a (model year 2010, black with black & silver overlay)
  • version 2b (model year 2011, black with black & silver overlay)
  • version 3 (model year 2012-13, black with dark blue & white overlay)
  • versions 4/4tb (model year mid-2014+)

With respect to version 1, version 2a:

  • increased the Mix knob range to go 100% wet at full clockwise
  • increased the Depth knob range to go to "near infinite" at full clockwise
  • tweaked the lower Depth knob range to sound less "slappy" and more like a small room
  • increased the size of the battery compartment to accommodate a larger battery (i.e., rechargeables)

With respect to version 2a, version 2b:

  • replaced the true bypass with a switchable buffered/unbuffered bypass
  • increased the wet signal headroom by about 6 dB
  • added the low battery indicator
  • reduced the wet signal level slightly to make it easier to add "just a touch" of reverb

Version 2b can be differentiated from 2a by the label on the bottom of the pedal or on the box, which indicates how to change the switchable bypass. Or, if no label is present, then you have version 2b.

With respect to the version 2b, version 3:

  • adds trails bypass
  • improves Mix knob taper: ultra-fine control from "just a touch" of reverb to 100% wet with no volume loss
  • adds variable headroom control for line level use at lower Mix knob settings
  • removes battery capability
  • removes switchable buffered/unbuffered bypass

With respect to version 3, version 4:

  • adds a Tone knob
  • changes the footswitch to a "soft" switch
  • adds selectable trails/normal/two-stage bypass
  • adds an option for true bypass

With respect to version 4, version 5:

  • moved in & out jacks to the top
  • added selectable reverb type — original Wet or W3T (in Immerse Mk II)
  • removed the option for true bypass