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Tech 21 Sansamp XXL

Hi-tech Overdrive Unit By Paul White
Published December 1995

Paul White tries out a new overdrive pedal that was clearly named after a very large T‑shirt.

This latest Sansamp product incorporates Tech 21's specially‑designed overdrive chip in a pedal. As it doesn't have a speaker simulator, you have to record via a device that does have one, or use an amp and mic it up.

At the heart of the unit is a complex chip, which is designed to model (in the analogue domain, of course!) the characteristics of a valve‑powered guitar amp, right down to the push‑pull output stage. The upshot is that the overdrive sound, and, equally as importantly, the responsiveness of tone, very closely matches that of a real amplifier.

The XXL's other claim to fame is that with the addition of the new Warp knob, it provides control over odd and even harmonics. The remaining controls (level, tone, and drive) are common to most stomp boxes, and in true stomp box tradition, a chunky bypass footswitch is provided. Power is supplied via 9V PP3 battery, though an external PSU may be used.

The Warp setting varies the available tones from overdrive through to a true tube tonality, and at more extreme Warp settings the level of the note being played also 'pumps', in much the same way as a valve amp compresses due to power supply sag. Even the passive tone circuit is slightly out of the ordinary — when its control knob is fully clockwise, it is essentially flat, but as you approach the mid position, the low frequencies are boosted, so fattening up the sound. When the knob is turned right down, the high end is also cut, leaving a very smooth tone.

In The Studio

The beauty of the XXL in the studio is that you can plug it into any half‑decent practice amp and create a huge sound that delivers noticeably more 'oomph' than most DI methods. Using an amp also gives you the chance to utilise real room acoustics in your recording. On the other hand, if you have a guitar preamp with an in‑built speaker simulator already, you can use the XXL to vastly increase the range of available sounds.

My first test was to use the XXL with my little Fender Champ amp and a Strat, and the results were simply superb — especially at lower drive settings, where the tonality of the guitar and the responsiveness of tone produced a sound that can only be described as classic. At higher overdrive levels, the sound becomes more saturated and very punchy, which is ideal for rock work — even the Strat's single‑coil pickups sounded very thick. Experimenting with the Warp control revealed that the harmonic balance makes a considerable difference to the type of tone achieved, and the best Strat sounds came with settings above the halfway point.

When I tried the XXL with my PRS guitar, the tone was excellent again, but this time I found that it wasn't possible to turn the XXL's drive control down far enough to give me that elusive in‑between blues tone.


Although aimed mainly at the live musician, this pedal can transform any small amp into a studio monster, and it also sounds good plugged into other preamps that have their own speaker‑simulator circuitry. The Warp Harmonics control makes this unit more versatile than any other four‑knob overdrive box I've used before, and the Sansamp circuitry produces a very convincing tube amp tone. As already mentioned, the drive range may be too restricted for those users who have powerful, humbucking guitars, and who want to get a subtle blues tone on occasion. The only way you can get the drive low enough is to turn the volume down on the guitar, and with most guitars, that results in some loss of top end. This limitation aside, the XXL is an excellent pedal which transcends the limitations of the usual overdrive box.


  • Excellent range of convincing tones.
  • Warp control really effective.


  • Minimum drive level still too high for some powerful humbuckers.
  • No speaker simulator built in.


The XXL sets a new standard for overdrive pedals and will be welcomed by guitarists for both stage and studio use.