Boss Xtortion XT-2

earthtonesaudio · Post by **earthtonesaudio** » 27 Jul 2009, 16:44

Here are the mods I did to mine:

-Swap one of the red clipping LEDs for Ge, one for Si (small signal types).
-Add 100k in parallel with R13
-Add 1k in parallel with R20
-Add 1M in parallel with R35
-Add 22k in parallel with R26
-Short R24
-Add 47n cap in parallel with C23

There are 2 reasons for doing all those things in parallel: it's obvious what and where the mods are, and easy to revert back to stock if desired (just snip out the added parts with a pair of side cuts).

Before I did these mods, it was easy to get a bad sound, impossible to get any good sounds from it (my subjective opinion of course). With the mods, it's a lot more flexible. It does several new awful sounds, plus some good ones.

Note that the R13 mod affects the bypass tone as well (increases tone suck). Perform this mod at your own risk.

yahoo! · Post by **yahoo!** » 28 Jul 2009, 15:03

do have soundclips for this?

mills · Post by **mills** » 28 Jul 2009, 17:11

Thanks for posting! I've been meaning to mod mine for a while and just haven't been able to find the time.

I'd been planning a few mods that I think were similar, but if you don't mind my asking what does the R35 mod theoretically do?
And, what would the capacitor mod do? I know it has to affect the punch knob, but other than what I think is a simulated inductor below it for the eq, I have a hard time understanding what IC2.1 (well, and 2.2) are doing...

devastator · Post by **devastator** » 28 Jul 2009, 17:17

thanks

Can you give more explanations about what do the mods on the sound?

earthtonesaudio · Post by **earthtonesaudio** » 28 Jul 2009, 19:50

I thought you'd never ask!
First, a helpful page: http://www.muzique.com/lab/gyrator.htm
Second, note that R37 is not labeled on the schematic. I'm pretty sure it was 820k.
Also R35 is a typo in my first post, it should be R37.

earthtonesaudio wrote:Here are the mods I did to mine:

-Swap one of the red clipping LEDs for Ge, one for Si (small signal types). clips on lower voltage signals/more distortion/asymmetric distortion/added germanium mojo
-Add 100k in parallel with R13 "increased tone suck" mod, with my guitar this slightly reduces bass and volume going in, and lets the guitar volume knob clean up the tone a little better. Note: this is a guitar-specific mod, and it affects the bypass tone as well, so apply this mod with caution.
-Add 1k in parallel with R20 more gain for "all" frequencies going into IC1.2, less of a mid cut when Punch knob is rotated fully CCW
-Add 1M in parallel with R35 Ack! This is a typo! I meant R37. Addign 1M in parallel reduces the Q and raises the center frequency of this gyrator to about 800Hz
-Add 22k in parallel with R26 This increases the center frequency of the mid scoop of the Contour control
-Short R24 This one has the most effect of all the mods. This lets you reduce the mid boost of the Punch control down to zero, and even beyond to cut mids. This is a very noticeable mod, drastically changes the capabilities of the pedal, but the original character is still available if you want it. If you only do one of these mods, do this one.
-Add 47n cap in parallel with C23 This brings the center frequency of this gyrator back down to about 600Hz while further reducing the Q.

There are 2 reasons for doing all those things in parallel: it's obvious what and where the mods are, and easy to revert back to stock if desired (just snip out the added parts with a pair of side cuts).

Before I did these mods, it was easy to get a bad sound, impossible to get any good sounds from it (my subjective opinion of course). With the mods, it's a lot more flexible. It does several new awful sounds, plus some good ones.

Note that the R13 mod affects the bypass tone as well (increases tone suck). Perform this mod at your own risk.

mills · Post by **mills** » 28 Jul 2009, 20:20

earthtonesaudio wrote:I thought you'd never ask!
First, a helpful page: http://www.muzique.com/lab/gyrator.htm
Second, note that R37 is not labeled on the schematic. I'm pretty sure it was 820k.
Also R35 is a typo in my first post, it should be R37.

Thanks for the link! I'd only seen the Geo Parametric EQ page and wasn't quite sure how to interperet the similar but not identical setup I've seen in a couple schematics... the calculator should make life easier when it comes time to mod a thing or two.

earthtonesaudio · Post by **earthtonesaudio** » 30 Jul 2009, 03:14

One final mod, now I'm quite satisfied with the pedal:

Relocate the top of C16 to the other side of R26.
The stock tone control goes from a sorta muddy tone fully counter-clockwise, to a deep mid scoop fully clockwise. Now it goes from a hollow/deep mid scoop at full CCW, to no scoop (centered), to a fuller-sounding mid scoop at full CW.

One of these days I'll figure out how to work the digital video camera and YouTube it, but not in the near future.

TheGaryAmes · Post by **TheGaryAmes** » 19 Feb 2021, 16:36

I see this is an old thread but nonetheless just for anyone else who might be searching for mods on this pedal....

I suggest these 2 changes:

I had really good results to my ears at least by changing R24 from 33K to 18k. I accomplished this by putting a 39K resistor across R24 instead of shorting it out as was suggested above in this thread. This creates a less drastic change in the sound that I found easier to adjust to my tastes and makes it easy to revert back to stock by simply snipping out the added parallel 39K resistor.

The other thing I did was to remove the C18 electrolytic .1uf capacitor and replace it with .033uf non-electrolytic cap which reduces the inherent woofiness of the pedal and helps it stay out of the way of the bass guitar and fit better in an overall mix. I then added a small switch, that adds a .015UF cap in parallel with the .033UF one so that I can switch between .033UF and .048UF. If one doesn’t want to go to the trouble of installing the switch I would suggest just using a .047uf capacitor in place of C18.

One could also install a .047uf cap and add a switch that puts another .047uf in parallel with the installed one to be able to switch back-and-forth between .047uf and approximately .1Uf (i e .094uf), which is then close enough to stock to make little audible difference when compared to the stock sound.

Of course if you’re Jack White and don’t play with a bass player you may like the stock boominess....

TheGaryAmes · Post by **TheGaryAmes** » 19 Feb 2021, 16:51

Oops I forgot to add that I also changed C21 from .033uf to .048uf by adding a .015uf cap across C21.
This slightly reduces a bit of the ice picky raspiness and makes for a slightly smoother sound.

bajaman · Post by **bajaman** » 19 Feb 2021, 21:44

Boss Corporation's biggest lemon - no wonder they discontinued it quickly

TheGaryAmes · Post by **TheGaryAmes** » 20 Feb 2021, 05:31

One has to wonder about the apparent lack of market research and proper marketing on this one for sure. It could have been a much more unique an useful pedal out of the box. I’m rather happy with the “punch” control at this point. The “contour” control could perhaps use some more work although changing the capacitor right before it changes its character a bit anyway. It reminds me a bit of the “shape” control on old Crate amps.

Gila_Crisis · Post by **Gila_Crisis** » 01 Mar 2021, 09:15

I just got one for very cheap (like 20$), I remeber back then in the last 90s I tried one a friend had, and I was mehhh.. a MEtal Zone can do the same.
Now I must admit it's not so bad after all these years: it has this very acid, industiral metal, broken radio sound on guitar and with synth it's also a lot more interesting!