Who plays Ernie Ball Cobalt Slinky strings: the documented pro users
Reviewed by the Change Your Strings editorial team ·
Seventeen pros have documented primary-source use of Ernie Ball Cobalt Slinky strings: Slash, John Petrucci, Steve Vai, Steve Lukather, Joe Bonamassa, Steve Morse, Tim Henson, Paul Gilbert, Kenny Wayne Shepherd, J Mascis, Jason Richardson, Keith Merrow, Dustin Kensrue, Wes Hauch, Dean Richardson, Ryan Bruce, and Tony Levin. Twelve more Ernie Ball artists are provisional Cobalt users without a direct quote on record.
How this list was assembled
Cobalt Slinky has a narrower confirmed user list than regular nickel Slinky because the Cobalt sub-line is only one of five wire lines Ernie Ball ships: nickel Slinky, RPS, M-Steel, Paradigm, and Cobalt. Many famous Ernie Ball endorsers, James Hetfield, Kirk Hammett, Jerry Cantrell, Mick Mars, Stephen Carpenter, Adam Jones, Synyster Gates, St. Vincent, are on other Ernie Ball lines and not Cobalt.
The list below is 17 confirmed plus 12 provisional Cobalt users, ranked by cultural weight. Every name in the confirmed tier has a primary-source citation or a documented Ernie Ball artist relationship that includes Cobalt by name. We do not pad this list with guesses. Provisional entries are flagged separately and explicitly labeled.
Confirmed Cobalt users (primary-source documented)
Primary sources for the table above: Premier Guitar Cobalt launch coverage (names the beta testers: Slash, Petrucci, Morse, Levin, Randy Jackson); Guitar World video features for Slash, Petrucci, and Morse; EB play-test videos for Vai, Lukather, and Gilbert; Ernie Ball Tim Henson signature page; Kenny Wayne Shepherd's Facebook post; EB blog String Theory recaps for J Mascis and Dustin Kensrue; EB Striking A Chord: Jason Richardson; Wired Guitarist: Merrow and Hauch of Alluvial; Equipboard pages for Dean Richardson and Ryan Bruce.
Provisional Cobalt users (likely Ernie Ball; line unconfirmed)
These twelve are documented Ernie Ball artists where the Cobalt sub-line is inferred from signature-guitar specs, aggregator sources, or string-line overlap, but a direct primary-source "I play Cobalts" quote isn't on the record. Treat them as a secondary tier. Do not cite these as Cobalt endorsements without additional sourcing.
Famous Ernie Ball endorsers who do NOT play Cobalt
The Cobalt list is narrower than the overall Slinky list because several of the most-famous Ernie Ball players are explicitly on other lines:
Ernie Ball endorsers, NOT Cobalt
Treating these artists as Cobalt users based on their Ernie Ball endorsement alone misleads readers. The five Ernie Ball wire lines, nickel Slinky, RPS, M-Steel, Paradigm, Cobalt, each have their own endorser rosters. If you want an artist's string match, check their individual rig page rather than assuming all Ernie Ball = Cobalt.
Not Even Slinky Cobalt (.012–.056)
Why this one: One of the heaviest Cobalt Slinky 6-string gauges Ernie Ball ships (the Mammoth Slinky Cobalt 12-62 goes heavier), built for Drop C and below.
Related
- Read the full Ernie Ball Not Even Slinky Cobalt review for the product-level breakdown.
- Compare the wire lines head to head: Cobalt vs nickel Slinky voicing comparison and all five Ernie Ball string lines compared.
- Individual rig pages: Slash, John Petrucci, Steve Vai, Tim Henson, Mark Holcomb.
- Shopping by tuning instead of artist? See the Drop C gauge and tension chart.
Frequently asked questions
Does James Hetfield play Cobalt Slinky?
No. Hetfield is a long-time Ernie Ball Regular Slinky (nickel) endorser for rhythm tracks across most of the Metallica catalog. He has not publicly moved to the Cobalt sub-line. See our James Hetfield rig page for the full gauge history.
Does Kirk Hammett play Cobalt Slinky?
Hammett uses Ernie Ball sets but on the RPS line: he hand-mixes the plain strings from RPS-10 Regular Slinky with the wound strings from RPS-11 Power Slinky, per his Ernie Ball String Theory episode. No documented primary-source quote puts him on Cobalts specifically.
Who was the first pro guitarist to play Cobalt Slinky?
Ernie Ball launched Cobalt Slinky in January 2012. Premier Guitar's launch coverage names the beta testers as Slash, John Petrucci, Steve Morse, Tony Levin, and Randy Jackson. Steve Vai and Steve Lukather appeared in separate Ernie Ball Cobalt play-test videos a few months after launch. Slash and Petrucci are usually credited as the most influential early adopters.
Why isn't Tim Henson on the main 'who uses Slinky' list?
Henson is a Cobalt user specifically, not a general Slinky user. His 2025 Ernie Ball signature set combines Cobalt wrap with Paradigm core-wire technology, a custom hybrid, not an off-the-shelf Slinky. See the Tim Henson rig page for the full breakdown.
What gauge Cobalt does Slash use?
Slash played Power Slinky Cobalt (.011 to .048) and was one of the named Cobalt beta testers at the January 2012 launch. His current Ernie Ball signature set is an .011 to .048 Paradigm-core nickel set, not Cobalt.
The full Power Slinky Cobalt set is detailed in the Cobalt gauges explained guide.
Does Stephen Carpenter (Deftones) play Cobalt Slinky?
No. Carpenter is on the Ernie Ball Paradigm line, coated/treated nickel-plated steel, not Cobalt. Paradigms dominate the downtuned-metal endorsement list because they handle drop tunings with more longevity than Cobalt.
How was this list sourced?
Each confirmed entry has a primary-source citation: Premier Guitar's January 2012 launch coverage, Ernie Ball String Theory and Striking A Chord episodes, Guitar World video features, Ernie Ball play-test videos, or the artist's own social media. Linked sources sit under the confirmed table. Provisional entries are Ernie Ball artists where Cobalt is inferred from signature-guitar specs or aggregator evidence without a direct quote. We explicitly do not pad this list with guesses. This page was re-verified claim by claim on 2026-06-09; three names were demoted or removed in that audit.
Why is the list this short?
Beyond these names, the sourcing evidence falls below the quality bar this page is trying to hold. Adding names without a primary source dilutes the trust readers place in the rest of the list. If you want a larger roster, we can add specific artists with a verified source, tell us the name and the citation.