Chameleon

Complex distortion and amp simulation pedal made famous (and expensive) by Kurt Cobain

   

 

The Chameleon is an amp sim and distortion rack effect module that compares to the Tech 21 SansAmp, SansAmp Classic, and SansAmp GT2.  These pedals are "tweaker heaven", offering a very large number of different control setting combinations.  The pedals were made in the 90's, and were used by many artists then and now, for both guitar and bass.  The pedal gained fame when Kurt Cobain used the original SansAmp pedal, most likely on the In Utero album and for many live shows, although it wasn't his only, or perhaps even his main, distortion pedal.  

 

Description

The GT Chameleon compares to the Tech 21 SansAmp pedals.  There are several SansAmp pedals from Tech 21.  The Chameleon comes in two configurations.  The first configuration compares to the original SansAmp pedal, which at a later date was reissued as the SansAmp Classic.  Other than having the word "Classic" added to the name, the Classic is the same as the original SansAmp pedal.  The second configuration of the Chameleon compares to the SansAmp GT-2.  The GT-2 is very similar but has a simpler set of control switches and slightly fewer options.  We'll limit our discussion here to those 3 models (original, Classic reissue, and GT-2) which are captured by our Chameleon (original/Classic reissue) and our Chameleon GT2 (GT-2 version).

As you probably know, Kurt Cobain famously used the original SansAmp pedal, although he was not the only big star to use it.  If you visit the Tech 21 website, you'll see a long list of well-known guitar and bass players, who have used their pedals in pretty much every style of music you can think of.

Oddly, the original, Classic re-issue, and GT-2 have all been in and out of production at various times since they were introduced in 1989.  The pedals are still in high demand.  At the time of writing this, the originals fetch $500-$1000 used, new ones (Classic and GT2) when available are around $230+.

So what is all the fuss about?  These two circuits are slightly different, but the intent is the same and their controls and tones have much more in common than different.  The GT-2 is a slightly "evolved" version of the original.  Both are meant to give you the ability to model different amps and mic-ing methods by setting a number of switches to route your signal through different parts of the circuit.  You get 4 knobs, one 3-way toggle switch (original/Classic only), and 8 DIP switches (aka Character switches) to create the tone of your choice on the original/Classic.  That's 768 different switch combinations, not counting all the possible settings of the 4 knobs which easily takes the number of distinct settings into the thousands.  That would normally be option overload, but of course many of those switch settings sort of go together to create classic amp tones.  Other combinations are either very similar or are less interesting.  But all settings are legitimate possibilities.  The GT-2 changes the toggle switch and 8 DIP switches to three 3-way switches.  That's far, far fewer combinations (27), but they are better organized and focused.

The Input switch on the original/Classic lets you select a base amp starting point.  The Lead setting corresponds to Marshall, the Normal setting corresponds to Mesa Boogie, and the Clean setting is for Fender and Hiwatt. 

The knobs allow you to control volume, drive, and tone in different ways.  The DIP switches and slider switches give you further control over tone, drive, and mic position.  These differ considerably between the original/Classic and the GT-2 and are described in more detail below.  As you can see, we broke from our normal control style and used two pairs of concentric black metal knobs.  Without the concentric knobs (and potentiometers behind them), we would need to make the modules three inches wide, a bit more space than we would like to use up in our enclosures.

All the controls are very effective, yielding a variety of amp tones that can cover any genre of music from metal to clean.  All are meant to sound like tube amps and use FET technology to achieve that goal.  The controls also interact with each other, having a slightly different effect depending on the settings of other controls.  As a result, it can definitely take some time to find your favorite settings.

The pedals included a buffer that was on and in your path even when the effect was off.  We offer that as an option on both configurations, but the default is to have the buffer on only when the effect is on.

The pedals were designed to go directly to the PA or mixer, without an amp or cab.  You can even listen to them with headphones plugged directly into the pedals.  But you can also run them into your amp, perhaps being careful to keep the amp settings mostly tone-neutral and clean.  With so many different settings and so much switch wiring inside, the original pedals would sometimes squeal or otherwise "misbehave" on some settings.  That's normal when tone, volume, and drive settings start nearing their maximums, and can be expected when you wander into that space either with the original pedals or our modules.

As you can guess from looking at the long list of famous users who are particular about their tone, the circuit works amazingly well at delivering a wide variety of all analog amp tones.  This is one of those circuits you might consider if you play in a cover band and need more amp tones than you really want to lug around.

The control configuration of both versions have a good deal of overlap.  While the circuits are considerably different, it is more a matter of doing the same sorts of things differently than it is a matter of different intents.  The settings on the GT2 version seem to be better organized and more intuitive, although offering fewer combinations to try.  Those fewer combinations are perhaps more focused on the "good" ones.

We don't recommend making component changes.  All the resistors, capacitors, etc are already high quality and selected to work well in this circuit.  In the original model, a FET transistor was used for the buffer.  We use the same one as the original used, but they are difficult to source, so we may substitute a different one, but still a FET - no audible change to the sound.  The GT2 buffer transistor we use is also either the same or tone-same as the original in that circuit.  The op amps are also FET-based.  We use slightly different packaging of those same chips that are the same inside, or other FET chips that again have the same tone.  FET is important to get the tube sound the pedals are known for.  The voltage needs to stay at 9V to produce the correct levels of distortion in the op amps.  The end result is that the modules sound essentially the same as the original pedals. 

Configurations

We offer two configurations.  The Chameleon compares to the original and Classic reissue SansAmp pedals.  The Chameleon GT2 compares to the SansAmp GT2.

These circuits already have so many features that we see no point in trying to add more.  We stick to the original designs.  The only interesting option is whether or not you want an always-on buffer like the originals or prefer a real bypass when the effect is off.  You have to work with the DIP switches of the original for a while to get the hang of it.  On the GT2, it is more straightforward - pick an amp, a mod, and a mic location.

  • Chameleon - Compares to the original and Classic reissue SansAmp pedals.

  • Chameleon GT2 - Compares to the SansAmp GT2 pedal.

 

Options

  • Always-On Buffer - Route your signal through a buffer even when the effect is off.  By default we switch the buffer on and off with the effect

 

Front Panel - Chameleon

  • On/Off indicator LED
  • Presence Drive - Adjusts upper midrange.  Turn up for crunch
  • Amp Drive - Adjusts distortion
  • Output - Volume control.  Suggested to adjust to unity with bypass volume level
  • High - Final high-end adjustment.  Suggested to use at halfway or less, all on for going to a studio mixer
  • Input switch -  LEAD: Marshall preamp tone with extra mids and highs, NORMAL: flat EQ, Mesa-Boogie tone, BASS: Fender/Hiwatt clean amp tone
  • DIP switches 1-8
    • 1 Mid-Boost 1, 2 Mid-Boost 2 - Both off: brightest, 1 on 2 off: next brightest, 1 off 2 on: warmer, Both on: fat
    • 3 Low Drive - On: flat EQ, Off: more highs
    • 4 Clean Amp - On: cleans up the OD, nice and chunky
    • 5 Bright Switch - On: when Amp Drive is on lower settings adds brightness.  Does less as Amp Drive is increased.
    • 6 Vintage Tubes - On: softer, less aggressive tone
    • 7 Speaker Edge - On: add presence
    • 8 Close Miking - On: boosts lows a small amount

Front Panel - Chameleon GT2

  • On/Off indicator LED
  • Drive - Adjusts OD/gain level
  • Low, High - Active tone controls
  • Level - Volume
  • Amp - Select TWEED for Fender, BRITISH for Marshall, or CALIFORNIA for Mesa Boogie.  These adjust multiple aspects of the tone, gain, and feel for each amp style
  • Mod - Select CLEAN for stock tube amp, HI GAIN for an extra pre-amp tube gain stage, and HOT WIRED for hard-driven high-gain
  • Mic - Choose the mic placement in a "dead room/no ambiance" sound.  Select CLASSIC for mostly flat "distant mic" tone, provides a bit more mids and cuts through better than other settings.  Select CENTER to mimic "close mic" aimed at the center of the speaker cone, provides more highs and lows for big all-out crunch tones.  Select OFF AXIS to mimic "close mic" but at the edge of the speaker cone instead of the center, smooths out the tone

 

Rear Panel - both

  • Audio In
  • Audio Out
  • On/Off Footswitch
  • On/Off Override
  • DC Power
  • DC Power LED

 

Module Width

  • 2"
  • wing versions not currently available

 

Power Consumption (aprox)

Chameleon:  9-13mA

Chameleon GT2:  15-19mA

 

Base Configurations

Part # Description List Price
MOD-CHAMELEON Chameleon module $275
MOD-CHAMELEON-GT2 Chameleon GT2 module $275

 

Options

Part # Description List Price
MOPT-CHAMELEON-BUF Switch to Always-On Buffer $0