Ernie Ball Cobalt Slinky gauges explained: the full 8-set lineup, picked by tuning
Reviewed by the Change Your Strings editorial team ·
Ernie Ball ships eight Cobalt Slinky sets spanning .008–.038 (Extra) up to .012–.056 (Not Even). Pick Regular Slinky Cobalt (.010–.046) for E or Eb standard, that's the default. Step up one gauge for every whole-step down: Power Slinky (.011–.048) for Eb / Drop D, Beefy Slinky (.011–.054) for Drop D to Drop C, Not Even Slinky (.012–.056) for Drop C and below. Lighter gauges (Extra, Super, Hybrid) are for E standard on faster-playing or lighter-touch setups.
The full Cobalt Slinky gauge lineup
Ernie Ball ships eight standard 6-string Cobalt sets, plus 7-string and 8-string extensions and a bass line. All use the same cobalt-iron wrap-wire alloy; the only thing that changes set to set is string gauge. Pick by tuning first, scale length second, hand strength third.
How to pick
Step 1: match gauge to tuning. Every whole step of detuning adds about one gauge step in heavier string requirement. E standard defaults to .010s; Eb or Drop D defaults to .010–.048 or .011s; Drop D or D standard wants .011s or .010–.052; Drop C wants .011s or .012s; Drop B wants .012s or a baritone set. Going lighter than this at a given tuning causes flappy low strings, intonation drift under hard picking, and eventual tuning stability issues.
Step 2: adjust for scale length. A 25.5" Fender-scale guitar is the baseline for these recommendations. On 24.75" Gibson scale, tensions drop roughly 15%, so you can comfortably run one gauge heavier than the Fender recommendation, a Gibson-scale guitar in Drop D often plays best on Power Slinky (.011–.048) rather than Regular. On 27" baritone scale, tensions jump enough that you want to drop one gauge lighter than a same-tuning Fender recommendation.
Step 3: adjust for hand strength and playing style. Heavy-handed players and hybrid-pickers push strings harder and can tolerate, or benefit from, the next gauge up. Light-touch fingerstyle players and extreme benders (1.5-step or full-step bends as a default vocabulary) benefit from the next gauge down.
Subset-by-subset notes
Extra Slinky Cobalt (.008–.038, EB 2725)
The lightest Cobalt gauge. Almost exclusively a shred/speed-metal set for E standard players who want the absolute lightest bending feel. Not recommended below E standard; the low .038 will flap. Favored by a small but vocal player cohort, Paul Gilbert runs Super Slinky (.009) as his default but keeps Extra Cobalt around for high-speed passages.
Super Slinky Cobalt (.009–.042, EB 2723)
Steve Vai's primary gauge. The default .009 set across modern shred and fusion. If you came up playing EVH, Vai, or Satriani recordings, this is the Cobalt set most likely to match what you were hearing. E standard only; on Eb standard, most players should step to .010 Regular Slinky.
Regular Slinky Cobalt (.010–.046, EB 2721)
The default. What Ernie Ball recommends as the starting Cobalt set for most players. E standard or Eb standard, 25.5-inch scale, rock / blues / hard rock / blues-rock. Steve Lukather played this gauge for his Cobalt years (he has since moved to Paradigm). If you don't have a reason to pick a different gauge, pick this one.
Power Slinky Cobalt (.011–.048, EB 2720)
One step heavier than Regular. The Slash gauge, documented across his Cobalt era. Best for Eb standard or Drop D on Fender scale, or E standard for players with a heavy hand who want more low-end definition. Borderline for Drop D on Gibson scale; many players prefer stepping all the way to .011–.052 Skinny Top Heavy Bottom for Drop D work.
Skinny Top Heavy Bottom Cobalt (.010–.052, EB 2715)
The mixed-gauge specialty set. Light-gauge top three (.010, .013, .017) for leads and bends; heavy-gauge bottom three (.030, .042, .052) for Drop D rhythm. The set of choice for players who live in a mix of E standard and Drop D, Dean Richardson's primary rig, and referenced in several Ryan Bruce YouTube rig breakdowns.
Beefy Slinky Cobalt (.011–.054, EB 2727)
The Drop C default. A step up from Skinny Top Heavy Bottom on the bass side, with a matched .011 top string. Handles Drop C and C standard on 25.5" scale electrics without flapping, without forcing you up to the full .012 Not Even set. Dustin Kensrue's Cobalt gauge of choice on his Thrice rig.
Not Even Slinky Cobalt (.012–.056, EB 2726)
The heaviest standard Cobalt set. Built for Drop C, Drop B, C standard, and baritone B standard. Wes Hauch runs this gauge on his 6-string; it's the reference for "I play passive pickups and I want the low string to punch through a high-gain mix." Not for E standard, at E, it's uncomfortable for most players and wasteful of the gauge. See our full Not Even Slinky Cobalt review for the full breakdown.
7-string and 8-string Cobalt
- Slinky Cobalt 7-string (EB 2730, .010–.062): B standard or Drop A on 25.5" or 26.5" scale. Mark Holcomb's primary gauge on Periphery rigs.
- Slinky Cobalt 8-string (EB 2732, .010–.074): F# standard or Drop E on 27" or 28.625" scale.
- Baritone-specific: The 7-string set plus a heavier single low string is the common custom build for players tuning below Drop A on 6-string scale.
Not Even Slinky Cobalt (.012–.056)
Why this one: The heaviest standard Cobalt Slinky. Drop C and lower, 25.5-inch scale, passive pickups that need definition under gain.
Picking by tuning, quick reference
- E standard (light touch): Extra Slinky Cobalt (.008) or Super Slinky Cobalt (.009).
- E standard (medium): Regular Slinky Cobalt (.010).
- E standard (heavy hand): Hybrid Slinky Cobalt (.009–.046) or Power Slinky Cobalt (.011).
- Eb standard: Regular Slinky Cobalt (.010) or Power Slinky Cobalt (.011).
- Drop D: Power Slinky Cobalt (.011) or Skinny Top Heavy Bottom Cobalt (.010–.052).
- D standard: Power Slinky Cobalt (.011) or Beefy Slinky Cobalt (.011–.054).
- Drop C: Beefy Slinky Cobalt (.011–.054) or Not Even Slinky Cobalt (.012–.056).
- C standard: Not Even Slinky Cobalt (.012–.056).
- Drop B: Not Even Slinky Cobalt (.012–.056) or the 7-string set stripped down.
- B standard (7-string): Slinky Cobalt 7-string (.010–.062).
Next steps
- The canonical deep-dive: Not Even Slinky Cobalt (.012–.056) full review.
- Voicing vs nickel: Cobalt vs nickel Slinky comparison.
- All five Ernie Ball wire lines: Slinky vs RPS vs M-Steel vs Paradigm vs Cobalt.
- Who's on what gauge: 30 documented Cobalt pro users.
- Tuning targets and scale physics: String gauge and scale length reference.
Frequently asked questions
Which Cobalt Slinky gauge should I buy first?
Regular Slinky Cobalt (.010–.046, EB 2721) if you play in E or Eb standard on a 25.5-inch scale electric. That's the set most Cobalt players start on, and it's what Ernie Ball recommends as the default. Only step heavier or lighter if you have a specific reason, tuning, hand strength, or scale length.
Is the .012–.056 Not Even Slinky Cobalt too heavy for E standard?
For most players, yes. At E standard on a 25.5-inch scale, .012–.056 produces 70+ pounds of total tension, stiff under bends and harsh on a guitar set up for .010s. Use this gauge for Drop C, Drop B, C standard, or D standard. For E standard, drop to Regular Slinky Cobalt or Power Slinky Cobalt.
What's the difference between Beefy Slinky Cobalt and Not Even Slinky Cobalt?
One gauge step. Beefy Slinky Cobalt is .011–.054 (EB 2727), Not Even Slinky Cobalt is .012–.056 (EB 2726). Beefy is the sweet spot for Drop D and some Drop C setups; Not Even is for Drop C and below where you need the extra low-end rigidity. Most Drop C players run Beefy; most Drop B players run Not Even.
Does Ernie Ball make 7-string Cobalt sets?
Yes. The Slinky Cobalt 7-string (EB 2730, .010–.062) covers 7-string in B standard or Drop A. Many 7-string players like Mark Holcomb run the 7-string Cobalt set as their daily driver. There's also an 8-string Cobalt (EB 2732, .010–.074) for players tuned to F# or Drop E.
What about Cobalt bass strings?
Ernie Ball Cobalt Flatwound and Cobalt Roundwound bass sets exist and ship in standard bass gauges (.045–.105, .050–.105, 5-string variants). Tony Levin was on the development team for Cobalt bass. The voicing difference, brighter, more output, tighter low end, carries over from the guitar line.
Can I mix gauges across the Cobalt range?
Yes. The Skinny Top Heavy Bottom Cobalt (.010–.052) is the classic mixed set, light top three for leads, heavier bottom three for Drop D rhythm. It's the go-to set for players who want to solo in standard and drop the low E to D mid-song. Dean Richardson and Ryan Bruce both run this set on various guitars.
Does gauge affect Cobalt's voicing characteristics?
The voicing change, louder output, more upper midrange, is inherent to the cobalt-iron wrap alloy, not the gauge. You get the same tonal profile from .008 Extra Cobalt and from .012 Not Even Cobalt. Heavier gauges push it further because there's more wrap-wire mass moving in the pickup field, but the character is the same.