Peavey Rage 158 amps are inexpensive and small, therefore making them a favorite among beginning guitar players and those on a short budget. So it stands to reason that they're often a guitarist's first practice palate for learning about things like good tone and quality gain structure. Because the Rage is inexpensive, it often gets the reputation for sounding cheap and amateurish. But with a little patience, experimentation with the equalizer and good guitar technique, any guitarist can use the Rage to achieve tones from the sparkling clean to the hellishly high-gain.
Setting your EQ
Turn the low-range knob clockwise to a setting of 5 to 7. This will vary depending on the type of guitar you are using, and which pickup is sending a signal to the amp. The goal with the low-range setting is to dial in plenty of low frequencies without causing the amp speaker to vibrate.
Turn the mid-range knob clockwise to a setting of 7 or above. Many rock and metal guitarists choose to scoop all the midrange out of their tone, thinking it will make the guitar sound bigger. This is a mistake; the mid-range is where your guitar sound lives.
Turn the high-frequency knob clockwise to a level of 5 to 7. Again, this will vary depending on your taste and the type of guitar you're using. The key with the high-range setting is to dial in enough without causing the tone to sound metallic or nasally.
Setting your lead tone and clean tone
Turn the pre-gain knob to a setting of 4 to 6. Many guitarists make the mistake of turning this knob all the way up; this will kill the clarity of your tone and cause feedback at even low volumes. The pre-gain knob is second from the left.
Turn the post-gain channel (the knob directly to the right of the pre-gain channel), clockwise to a setting of 2 to 3. This is essentially a volume knob, so set it as loud as you like without causing feedback.
Turn your clean tone (the knob farthest to the left) clockwise to a setting approximately 80 percent of your lead tone volume.
Find the "Modern/Vintage" switch, and choose which setting you prefer. The modern tone is sharper on the high end, while the vintage tone has more low and mid-range overtones.