"High-Gain Plexi Brown Sound"



The 12K68 amp sim rack effect module compares to high-gain, Marshall plexi distortion pedals based on the Ed Guidry Brown Sound In a Box II (BSIAB2) circuit.  The Wampler Pinnacle is one of those pedals, designed to get you into EVH brown sound tones.



The name "12K68" comes from the 12xxx serial number of Eddie Van Halen's famous 1968 Plexi amp.  The circuit is designed to deliver the Brown Sound which EVH made popular using his Plexi amps.  This module is meant to be run wide open, just like a dimed Plexi.  It can be dialed back for lower gain Plexi tones, but clean tones are not to be found.  It's all about the high gain.

With very high gain, there is always the possibility of noise and squealing.  There are noise reduction options, which should be considered, especially with the Boost option.  There is a trimmer on the board which adjusts the maximum gain level.  The default setting is probably on the high side.  If you experience squealing with Gain, Volume, Tone, and/or Boost cranked up, then you've exceeded the max gain.  Just turn something down a bit until you get back to a gain level that works.  If this happens too early on your controls, then you can adjust the trimmer to lower the gain.  Turning the trimmer down won't appear to impact the gain much, but it can dramatically reduce noise and squealing and it affects the Volume.  The trimmer is touchy - most of the good settings are within a small range of adjustment.



  • 12K68
  • 12K68 Summit

The configurations of the 12K68 module compare to pedals based on the Ed Guidry Brown Sound In a Box II (BSIAB2) design.  The 12K68 Summit compares to the Wampler Pinnacle, which has much in common with the BSIAB2.  The two configurations have a couple of differences.  The Summit has a footswitch-controlled Boost, a modified Tone section, and a Bright/Dark switch to shift the overall range of the Tone control.  They have a very similar high-gain tone, with a good range of Tone adjustment, although the Summit offers some extra tone-shaping capabilities.




No buffers in either configuration.



  • Bass Boost Switch - On one setting this switch provides the normal bass response of the module.  The second setting provides an increased bass response, although that increase can be subtle for guitar.  Since more of your signal is allowed into the circuit, you may also get a little more noise when you engage the Bass Boost.  You may need to turn down the Volume, Gain, or Tone to compensate.  Not recommended for Summit configuration due to squealing.
  • No Shape - The Shape control is included in both configurations.  The Shape control can be removed to make the 12K68 circuit more like the Brown Sound In A Box (BSIAB, not BSIAB2) circuit.  Not available with Summit configuration (Shape control is required for Summit)
  • Hi Cut Switch, Extreme Hi Cut Switch - These provide a high-cut at the very end of the circuit to chop out unwanted treble and noise.  They can have a substantial impact on the highs.  Both versions of the high-cut work at the same frequencies, but the Extreme Hi Cut does it twice, reducing the impacted frequencies even more.  If you get the Extreme Hi Cut, there are two cables from the switch to the board.  If you unplug one of the cables, you get the Hi Cut instead.  Not available for Summit configuration.
  • Hi Cut - This is an unswitched option, available only for the Summit configuration.  It cuts treble content and noise near the end of the circuit.  We can adjust this when we build the module from "minimal trim - keep most of the treble and lots of the noise" to "heavy trim - chop some highs and most of the noise".  By default we provide "medium trim - keep as much high end as possible without causing squealing".  Of course, we can only test this with our setup, so the results may vary a bit with different setups.
  • Boost Toggle - The Summit configuration comes with a Boost function for use with a footswitch.  If you prefer, we can put the Boost on a front panel toggle switch so that the second footswitch is not needed.
  • No Boost - If you don't want the Summit Boost at all, we can remove it.  Building the Boost into the circuit requires leaving some "room" in the gain structure so that when the Boost is engaged you don't jump directly into high-gain overload and squealing.  That means that when the Boost is off, the maximum gain is not available.  That's probably not a problem since there is so much gain available.  And, of course, you can always run with the Boost on.  Without the Boost, you can just set the Gain the way you want and have the whole range available without the Boost.
  • Components - Metal film resistors are used by default to reduce noise.  A mixture of capacitor types is also selected to reduce noise.


Front Panel

  • Volume / Level
  • Gain
  • Tone
  • Shape - Gives Tone control different voicings to work with, focused mostly on the midrange
  • (Summit) Bright/Dark
  • (optional) Bass Boost
  • (optional) Hi Cut, Extreme Hi Cut
  • (optional) Boost


Rear Panel

  • Audio In
  • Audio Out
  • On/Off Footswitch
  • On/Off Override
  • DC Power
  • DC Power LED
  • (optional) Boost Footswitch
  • (optional) Boost Override


Module Width

  • 1.5" standard
  • 2" with options
  • 2" left wing available for standard (4) control 12K68 configuration
  • 1.5" right wing available for standard (4) control 12K68 configuration


Power Consumption (aprox)

8 - 16mA


Base Configurations

Part # Description List Price
MOD-12K68 12K68 module $199
MOD-12K68-SUMMIT 12K68 Summit module $239



Part # Description List Price
MOPT-12K68-BBS Bass Boost Switch $19
MOPT-12K68-NS No Shape $0
MOPT-12K68-HCS Hi Cut Switch $19
MOPT-12K68-EHCS Extreme Hi Cut Switch $19
MOPT-12K68-SHC Summit Hi Cut $0
MOPT-12K68-BT Boost Toggle $0
MOPT-12K68-NB No Boost -$9
MOPT-12K68-CC Component Changes TBD



Part # Description List Price
MPT-12K68-CA Replacement pot, switch, jack, LED cable assembly $19
MPT-12K68-KNB Replacement control knob $2
MPT-12K68-PB Replacement power board $29
MPT-12K68-SB Replacement switching board $29