Fender Blenders have more gain than you'd ever need or know what to do with and underneath the ton of fuzz is this slight octave effect. When you play a note and hold it & vibrato it a bit, the blender will start off with the note you play, and a harmonic generated one octave above the note you play, and gradually, the actually note you're holding disappears under the fuzz, and you're left with a squealing sustained octave that was generated by the pedal. It's wonderfully sick. And just when you thought it couldn't get any louder or more gained out, there's a boost button. Billy says it sounds like the end of the world, and I have to say he's right. You can hear the blender on MCIS in "Bullet with Butterfly Wings" at about 1:30 when the speakers come in really distorted. Also, it sounds like the blender was used for rhythm in "XYU" where you can't distinguish one chord from the next near the end. If you have Vieuphoria, that scene in Japan where they play "Slunk" with through those two JCM 800 2203 heads, the distortion is all coming from the Fender Blender. It makes the guitar sound unintelligible.
[product reviews on ultimate guitar]