Who plays Ernie Ball Cobalt Slinky strings: the 30 documented pro users
Reviewed by the Change Your Strings editorial team ·
Twenty 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, Tony MacAlpine, Keith Merrow, Dustin Kensrue, Wes Hauch, Mark Holcomb, Dean Richardson, Albert Lee, Ryan Bruce, and Tony Levin. Ten 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 20 confirmed plus 10 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
Provisional, Ernie Ball endorsers with likely Cobalt exposure
These ten 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 Do not cite these as Cobalt endorsements without additional sourcing.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:
- James Hetfield (Metallica): Regular Slinky nickel, documented across most of the Metallica catalog. Cobalt is not his set.
- Kirk Hammett (Metallica): Regular Slinky nickel for lead tracking; documented primary sources point to standard Slinky rather than Cobalt.
- Stephen Carpenter (Deftones): Ernie Ball Paradigm, the coated/treated line, for his downtuned 8-string work. Paradigm is Ernie Ball's longevity line; Cobalt is the voicing line.
- Jerry Cantrell (Alice in Chains): Ernie Ball Paradigm, not Cobalt.
- St. Vincent (Annie Clark): Regular Slinky nickel on her signature Ernie Ball Music Man instruments.
- Adam Jones (Tool): Ernie Ball, but on the RPS sub-line rather than 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: The heaviest Cobalt Slinky standard gauge, used by Wes Hauch for drop tunings and referenced in the Tim Henson 2025 signature development.
Next steps
- 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 primarily on the standard Slinky nickel line for lead tracking. 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 with a group of beta testers including Slash, John Petrucci, Steve Vai, Steve Lukather, and Steve Morse. Those five appear together in the January 2012 Guitar World launch video. 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 uses Power Slinky Cobalt (.011–.048). He has been on record about being one of the first Cobalt beta testers in late 2011 and appears in the launch Guitar World video in January 2012. See the Slash rig page for full sourcing.
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 either a primary-source citation (Ernie Ball launch video 2012, Ernie Ball String Theory episodes, interviews in Guitar World / Premier Guitar / Guitar.com, or the Ernie Ball artist page) or a documented active artist-relationship. 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.
Why stop at 30?
Beyond 30, 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.