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guitar edge st-9 pro+ review

The following article was originally published in Guitar Edge magazine.

review of maxon st-9 pro+ supertube overdrive by guitar edge magazine


Review: Maxon ST-9 Pro+ Super Tube Overdrive

Listen to the Maxon ST-9 Super Tube Overdrive
Released in 1979, Maxon’s TS-808 “Tube Screamer” pedal (sold under the Ibanez name) was one of those destined to become a classic. In the three decades since its introduction, it has become, as effects guru Tom Hughes calls it, “the quintessential overdrive.” Of course, from the start, the Tube Screamer’s trademark frequency hump has been both a signature and an Achilles’ heel, leaving some rockers wishing for a little less midrange and a little more low end.

Maxon addressed this in 1982 with the release of the rare ST-9 Super Tube Screamer, which retained much of the original 808 circuit, but allowed guitarists to tweak that hump to their heart’s content. Although those original examples now go for a pretty penny on sites like eBay, Maxon has decided to reissue the ST-9, with a few worthy improvements, as the ST-9 Pro+ Super Tube. This month we put it through its paces to see just how it stacks up to its forefathers.

The ST-9 Pro+ brings back the familiar Drive, Tone, and Level controls, while the original Mid Boost knob has become the Mid Enhance setting, although they have much the same function. The ST-9 Pro+ also adds true bypass switching, selectable voltage (9 or 18-volt), and a new Classic/Low Boost switch, giving users even more options to sculpt their tone.

Sound and Ease of Use
After testing the ST-9 Pro+ with an Ibanez RG321 and a Fender Stratocaster, run into an Orange Tiny Terror and an Electro-Harmonix .22 Caliber power amp, into an Orange 2x12 cab, the first thing that jumped into my mind was that this pedal truly excels as a lead boost—and I’m very picky about my lead boosts (so much so that I usually take only a modded wah and a clean boost to gigs). A good lead boost lets you keep that great rhythm tone, then kicks your amp into “natural overdrive” when it’s engaged. The ST-9 Pro+ is perfect for this application, and the Mid Enhance knobs allows you to dial things in so that your lead cuts right through the mix.

That’s not to say rhythm guitarists won’t have plenty of fun with the ST-9 Pro+. The pedal never got muddy or lost definition, even when placed into the perfectly fattening Low Boost mode (which provided more bass than I ever thought possible in a Tube Screamer variant). Of course, if you’re looking for that vintage TS sound, the Classic mode delivers it in spades (with even more midrange available via the Mid Enhance control). Switching the pedal’s voltage from 9 to 18 volts may shorten your battery’s life, but it also opens up a whole new voicing for the unit—the clarity and headroom are greatly increased, as are the dynamics of the unit. In short, the ST-9 Pro+ is packed with improvements, and may very well be one of the most versatile ODs on the market now.

Is It For You?
With a bevy of controls and options, the ST-9 Pro+ is poised to please both Tube Screamer purists and reach some audiences who may have written it off as “not their thing” in the past. Lead players will love dialing in their perfect solo tone, while rhythm players will dig on that classic TS mojo without losing the bottom end. Sometimes you can improve on a good thing.


  • True bypass switching
  • Selectable 9 or 18-volt operation (via internal dip switch)
  • Controls for Level, Drive, Tone, Mid Enhance, Low Boost/Classic switch
  • Solid construction
  • Versatile overdrive and lead boost tones


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