Ernie Ball Slinky Cobalt 6-String Electric Bass Strings (.032–.130) review: John Myung's factory Bongo 6 spec

Ernie Ball's Slinky Cobalt 6-String Electric Bass Strings is the only 6-string gauge in the brand's Cobalt bass line, .032 to .130, wound in cobalt alloy instead of nickel-plated steel. Ernie Ball's own product page describes the Cobalt bass family as engineered "to maximize output and clarity," giving players "an extended dynamic range, incredible harmonic response, increased low end, and crisp, clear highs," with cobalt producing "a stronger magnetic relationship between pickups and strings than any other alloy previously available."

It's also a factory-documented spec, not just a catalog listing. Music Man's own specifications page for the John Myung signature Bongo 6, the artist-series bass Myung has played through his long run with Dream Theater, lists its strings as "32w-45w-65w-80w-100w-130w (Cobalt Bass)," matching this exact set gauge for gauge.

This set also closes out Ernie Ball's roundwound Cobalt bass catalog on CYS. The 4-string spread (Extra through Power Slinky) and both 5-string spreads (Super, Regular, and Power) already had CYS pages; this 6-string set was the one gauge still missing.

For the fully measured Cobalt vs nickel breakdown (output dB, brightness curve, longevity, bend feel), see Cobalt vs nickel Slinky: the voicing difference, measured. Ernie Ball actually ships a nickel version of this identical gauge too: the Slinky Nickel Wound Long Scale 6-String Electric Bass Strings (SKU P02838), same .032 to .130 spread, nickel-plated steel instead of cobalt alloy, at a lower price. The closest non-Cobalt 6-string alternative already reviewed on CYS is D'Addario's EPS170-6 ProSteels, a stainless-steel-wrapped set at the same .032 to .130 spread.

Ernie Ball ships nine Cobalt bass gauges across three string counts. This is the only one built for 6-string:

• 4-string, lightest: Extra Slinky Cobalt Bass (SKU 2735), .040–.060–.070–.095.
• 4-string, light: Super Slinky Cobalt Bass (SKU 2734), .045–.065–.080–.100.
• 4-string, hybrid: Hybrid Slinky Cobalt Bass (SKU 2733), .045–.065–.085–.105.
• 4-string, standard: Regular Slinky Cobalt Bass (SKU 2732), .050–.070–.085–.105.
• 4-string, heaviest: Power Slinky Cobalt Bass (SKU 2731), .055–.075–.090–.110.
• 5-string, light: Super Slinky Cobalt 5-String Bass (SKU 2737), .040–.060–.070–.095–.125.
• 5-string, standard: Regular Slinky Cobalt 5-String Bass (SKU 2736), .045–.065–.080–.100–.130.
• 5-string, heaviest: Power Slinky Cobalt 5-String Bass (SKU 2738), .050–.070–.085–.105–.135.
• 6-string, this set: Slinky Cobalt 6-String Bass (SKU 2739), .032–.045–.065–.080–.100–.130, the only 6-string gauge in the line.

Full picture of how the Cobalt name works across Ernie Ball's guitar catalog too: Cobalt Slinky gauges explained. Full documented roster of Cobalt users, guitar and bass: Who plays Cobalt Slinky strings.

Dream Theater bassist John Myung's Music Man signature lineup spans a 4-string (the John Myung 4, released 2022) and this 6-string Bongo, the instrument he's been most closely associated with for most of his career. Per Music Man's own specifications table for the John Myung Bongo 6 HH, that instrument ships from the factory strung with "32w-45w-65w-80w-100w-130w (Cobalt Bass)", this exact set.

Ernie Ball also documents Myung as a longtime Cobalt player on its own String Theory artist feature, a brand-level endorsement that lines up with the factory spec on his signature 6-string.

He isn't the only extended-range bassist CYS covers. Thundercat plays a documented 6-string, though his is strung with Dean Markley SR2000 Medium Custom, not Ernie Ball. Different brand, same instrument category: a working 6-string bassist reaching for a compound alloy set instead of plain nickel.

• 6-string bass players building a rig around Myung's exact factory spec. Music Man's own spec sheet ties this set directly to the Bongo 6.
• Players who already like Cobalt's output and low-end bump on a 4-string or 5-string Ernie Ball set and are stepping up to a 6-string instrument without switching alloys.
• Prog, fusion, and session players who need the extra top-string range for chords and melodic lines without leaving the Cobalt family.

• Players chasing maximum string life. Cobalt is uncoated, the same wear curve as any uncoated roundwound; Ernie Ball's coated longevity line is Paradigm (Everlast nano-treatment), not Cobalt.
• Budget-conscious 6-string players. Ernie Ball's own Slinky Nickel Wound Long Scale 6-String Bass (SKU P02838) ships the identical .032 to .130 gauge in nickel-plated steel for less than the Cobalt upcharge.
• Drop-tuned 6-string setups below B standard. The .130 low string is built for B standard; Ernie Ball ships no heavier 6-string Cobalt option, so a lower tuning means custom singles instead.

The thin .032 high C is the string most likely to snap if a nut slot is cut rough or too narrow, so a proper setup check (nut slot width, saddle spacing, truss rod relief) matters more on this gauge than on a standard 4-string set. Break-in runs about the same as any fresh roundwound: 15 to 20 minutes of playing before the top end settles. Stretch each string, pull up gently a few times, retune, and repeat before a gig or session, paying extra attention to the high C until it holds pitch.

Slinky Cobalt 6-String Electric Bass Strings is Ernie Ball's one purpose-built answer for extended-range bass at six strings: a .032 to .130 gauge that keeps the same low end as the 5-string Regular Slinky Cobalt Bass and adds a high C on top, wound in the cobalt alloy that Music Man's own spec sheet ties directly to John Myung's signature Bongo 6.

If you're already running Cobalt on a 4- or 5-string and adding a 6-string to the collection, this keeps the voicing consistent. If you're chasing the lowest price instead, Ernie Ball's own nickel-wound 6-string at the identical .032 to .130 gauge (SKU P02838) costs less.