The RMA Mudlark is a somewhat straight forward circuit conceived after I rocketed past my target price point with the Dirty Doper. It is comprised of seven discrete transistors and supporting passive components that form up the following four sections:

  1. Initial gain
  2. Two point (Baxandall) equalization
  3. Two transistor fuzz
  4. Recovery amplifier

The sequence of the EQ and fuzz can be switched to allow more variation. As a standard the bypass LED is lit red when EQ feeds fuzz and blue when fuzz feeds EQ.


Pictured above is a fairly comprehensive illustration of the range of options.

At far left is the RMA Mudlark in standard trim. Upper left control defines level of cascading gain stages, upper right control is EQ shape (CCW rotation = bass up & treble down while CW rotation = bass down & treble up), toggle switch defines order, small knob is output level, and footswitch is bypass.

At middle left is a three knob variant with optional supercharger switch at LED point (LED has moved to between the two upper knobs). The supercharger is a somewhat refined feedback path that bolsters gain at the expense of sustain, at higher gain points it spills over into stepped oscillation territory not unlike the wandering artifacts of primitive harmonizer circuits.

At middle right we see the RMA Mudlark in five knob trim. The cascading gain section is now further tailorable with the initial and middle gain controls spanning the upper left corner of the enclosure. Output volume control has been relocated to upper right in the spirit of logical progression. Bass & treble now enjoy independence from one another. Also pictured on this build is optional footswitch upgrade for toggle function, and a cracked glass bezel LED that is being developed for a future circuit.

At far right is a five knob build tailored for table top applications (toggles replace footswitch).

Here’s the middle right unit in action:

Current pricing as follows:

  • Standard three knob Mudlark   $145 plus shipping
  • Five knob Mudlark variant       $175 plus shipping
  • Supercharger                            +$20
  • Upgrade toggle to footswitch   +$10
  • Cracked glass LED bezel         +$30

Mudlark configuration