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Ernie Ball Super Slinky Cobalt (.009–.042) review: the light-gauge Cobalt set

Reviewed by the Change Your Strings editorial team ·

Ernie Ball Super Slinky Cobalt (2722) is the .009–.042 light-gauge set in the Cobalt line. Cobalt-iron wrap on a tin-plated steel hex core gives passive pickups roughly 2–3 dB more output and a tighter upper midrange than nickel Super Slinky at the same gauge. Steve Vai is the documented anchor user. Pick it for shred-lead E standard, vibrato-heavy rock, and any context where you want the lightest practical Cobalt for fast picking and wide bending.

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Anatomy

Tone

Voicing through a passive pickup

Where this set sits in the Cobalt range

Super Slinky Cobalt is the lightest standard 6-string Cobalt:

  • E / Eb standard, lead-heavy or beginner-friendly: This set, Super Slinky Cobalt (.009–.042).
  • E / Eb standard, balanced: Regular Slinky Cobalt (.010–.046).
  • Eb standard / Drop D: Power Slinky Cobalt (.011–.048).
  • Light top, heavy bottom: Hybrid Slinky Cobalt (.009–.046) or Skinny Top Heavy Bottom Cobalt (.010–.052).
  • Drop C# / Drop C: Beefy Slinky Cobalt (.011–.054).

Picking guide: Cobalt Slinky gauges explained.

Who plays this set

Steve Vai is the documented anchor user. Vai moved onto Cobalts shortly after the line's January 2012 launch and has discussed the change on the record: "They move more with my emotional input." His primary instrument is the Ibanez JEM (25.5-inch scale, Evolution pickups), tuned typically to Eb standard for the looser bending feel.

Other documented light-gauge Cobalt users span the broader 6-string Cobalt roster, see Cobalt pro roster.

Best for

  • E standard lead-heavy playing. Shred, modern instrumental, fusion lead lines.
  • Eb standard with looser feel. Vai-style vibrato, multi-step bends, behind-the-nut moves.
  • Beginners on a 25.5-inch scale guitar. Lightest practical gauge for early bending without buzzing.
  • Picking-precision drills. The cobalt wrap's upper-mid push reveals attack inconsistencies, useful for practice.

Worst for

  • Drop tunings of any kind. The .042 low string flaps in Drop D and below.
  • Heavy palm-muted rhythm work. .032 and .042 don't have the mass to hold attack against quad-tracked production.
  • Acoustic-style hybrid picking with thumbpick. Light wound strings get pulled out of intonation by aggressive thumbpick attack.
  • Players who break .009s frequently. Step to .010s for durability; same Cobalt voicing in Regular Slinky Cobalt.

Install and break-in

Going from .010s to .009s drops total tension by roughly 6–8 pounds. The neck will pull back slightly with less string pull, which usually wants a quarter-turn truss-rod tighten to compensate. Nut slots accept .009s without filing if they were cut for .010s; intonation should be reset.

Break-in: 20–30 minutes of playing before the bright initial top end settles. Stretch each string before that.

Verdict

Super Slinky Cobalt is the lightest practical Cobalt set in the Ernie Ball catalog. If you play E standard or Eb standard, lean lead-heavy, want a shred-friendly bend feel, and want the cobalt voicing's extra output and upper-mid bite through a passive-pickup rig, this is the set. It's the gauge Steve Vai has run on his Ibanez JEM since the Cobalt line launched.

Pick this over nickel Super Slinky if you A/B them and hear the cobalt push as something useful for your tone. If you're not sure, demo nickel and Cobalt back-to-back and pick by ear; both work.

Affiliate link pending. Trace verifies the live Amazon ASIN for SKU 2722 at the next quarterly catalog audit. Reverse-lookup via productSlug is wired today.

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