VERTEX Steel String MKII

Features include

  • Dumble SSS tone from a compact stompbox
  • Based on model #001 of an original Dumble SSS amp
  • 33% slimmer and lighter than the original Steel String!
  • New Jazz/Rock toggle thickens up cleans and tightens up drive tones
  • Optional 9 to 18VDC operation (adapter not included)
  • True bypass
  • Designed & Assembled in California



When it comes to Continuum cleans or searing Blues lead tones, the Vertex Effects Steel String MKII — based on serial #001 of a legendary six-figure Steel String Singer amplifier— is an amazing tone-shaper and mild overdrive in an über compact, pedalboard friendly, size.  Whether you're hitting the front end of your favorite tube amp to give it a little more D-Style character or breathing a little more life into a solid state or backline amplifier, the Steel String MKII is a must for those that revere the classic Steel String amplifier clean tone.  Short of having a $250,000 SSS amplifier in your arsenal, the Steel String MKII is the next best thing!  It easily fits on any pedalboard, powered with any standard 9-18V power supply, and can be quickly dialed in with the gain, filter, and level controls with an added rock/jazz toggle to better shape the low-end EQ.


The Steel String MKII is about as easy as it gets when finding inspiring tones with your amp and guitar pairing of choice.  When the gain is below 50%, the Steel String will act as more of a clean boost with some D-style coloration (dialing the Filter, Volume, and Rock/Jazz settings to taste).  However, when the gain knob exceeds 50%, it begins to get into light overdrive territory and makes for an amazing mid-gain overdrive and an amazing pedal for stacking into mid-range style overdrives like the classic TS-style circuits.  In addition to being an amazing stand-alone overdrive, the Steel String can be a great EQ to balance out other harsher overdrive pedals when stacked, and can smooth some of those unwanted frequencies we often have to dial out of our mid and high gain pedals.  Whether you want to use the Steel String MKII as a Boost, Overdrive, or EQ shaper, there are literally endless possibilities that would make it an excellent choice for your pedalboard.


  • 1/3 the size — MKII manages to include the complete circuit of the Steel String MKI with ZERO compromise in tone.  By decreasing the size by over 33% players have all the benefits of the original Steel String in an even more pedalboard friendly size.
  • Added "Jazz/Rock" switch — As seen on many D-Style amplifiers, the Jazz/Rock toggle provides an even wider range of EQ voicing, in particular, in the low-end, working in combination with the filter control on the pedal.