Ernie Ball 7-String Regular Slinky Cobalt (.010–.056): the lighter 7-string Cobalt

Written with AI help · Updated 2026-08-25

Ernie Ball 7-String Regular Slinky Cobalt (2728) is the .010–.056 set, lighter than the 2730 (.062), fit for 7-string B standard and Drop A. Jason Richardson has named this exact 10-56 gauge as his own Drop A set on Ernie Ball's Striking A Chord podcast, stepping up to the 2729 (.011–.058) for Drop G. Cobalt voicing through passive pickups: roughly 2–3 dB louder than nickel, tighter upper midrange, more present pick attack.

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Anatomy

SKU: Ernie Ball 2728
MPN: P02728
Gauge: .010 – .056 (7-string Regular Slinky)
Gauge set: .010, .013, .017, .026, .036, .046, .056
String count: 7 strings
Core wire: Tin-plated hex steel
Wrap wire: Cobalt-iron alloy
Plain strings: Tin-plated hex-core steel (.010, .013, .017 plain)
Coating: None, uncoated
Winding: Standard roundwound
Intended scale: 25.5" primary
Intended tunings: B standard, Drop A (firm), Drop G# (marginal)
Total tension (25.5", B standard): ~118 lbs across 7 strings
Total tension (25.5", Drop A): ~112 lbs (low string detuned)
Launched: 2010s (Cobalt expansion to 7-string)
Package: Single pack

View Ernie Ball 7-String Regular Slinky Cobalt (.010–.056) on Amazon

Tone

Voicing through a passive 7-string pickup

Output: 2–3 dB louder than nickel 7-string Regular Slinky. Pronounced on the wound strings; subtler on plain.
Low string definition: .056 cobalt at B standard tension reads tighter than nickel at the same gauge. The tradeoff vs the .062 set is looser low-end tension for faster picking response.
Upper midrange: More present 2–4 kHz, helps the lead voice carry against quad-tracked rhythm.
Bend feel: Same as 6-string Regular Slinky on top, which is the most familiar bend feel on the 7-string market.

Where this set sits in the Cobalt range

7-String Regular Slinky Cobalt is the lighter of the two stock 7-string Cobalt sets:

7-string light top, light bottom (lead-leaning): This set, 7-String Regular Slinky Cobalt (.010–.056).
7-string standard rhythm: 7-String Slinky Cobalt (.010–.062, SKU 2730).
7-string lighter custom (Hauch/Merrow style): .009–.062 custom Cobalt.

Who plays this set

Jason Richardson is the documented anchor user, in his own words. Asked directly about his string gauges on Ernie Ball's Striking A Chord podcast, Richardson said: "I use Ernie Ball, primarily the Cobalts... gauge wise, for a Drop A, which is just standard tuning with the low string dropped a whole step, I use 10 to 56 for that." That's this exact set, on his Ernie Ball Music Man signature 7-string (now sold as the Jason Richardson HT). For Drop G, one step lower, he steps up a gauge to the 7-String Power Slinky Cobalt (.011–.058). This is Richardson's personal string choice, not the factory spec: Music Man's own current spec sheet lists the guitar as shipping stock with nickel-wound RPS 10 Slinky.

Best for

7-string B standard (B-E-A-D-G-B-E) on 25.5-inch scale. Comfortable rhythm tension.
Lead-heavy 7-string playing. Fast picking, sweep work, vibrato-driven leads.
Solo prog-metal and instrumental metal. Where the picking hand needs the lower-tension wound strings to keep up with the lead voice.
Players who don't tune below Drop A. The .056 low string handles Drop A; for Drop G# and below, step to 2730 (.062).

Worst for

Drop G# rhythm work. The .056 in G# is on the soft end; rhythm players want 2730 (.062).
8-string territory. Ernie Ball doesn't build a Cobalt 8-string; step to the nickel-wound 8-String Slinky (EB 2625, .010–.074) instead.
Players who quad-track heavy rhythms in Drop A or below. The .056 won't hold pick attack as cleanly under multi-take production as .062.

Install and break-in

7-string nut slots typically accommodate the .056 without filing if cut for the heavier 2730 set; coming from .062 down to .056 the slot is generously wide, no filing needed. Intonation should be reset on the low string after the gauge change.

Break-in: 30–45 minutes of play before the initial top end settles.

Verdict

7-String Regular Slinky Cobalt is the lead-friendly 7-string Cobalt for B standard and Drop A. The .056 low string keeps the rhythm side responsive without the firmer feel a .062 brings; the .010 plain top gives 6-string-style bend feel translated to 7-string. Jason Richardson has named this exact gauge as his own Drop A set, in his own words on Ernie Ball's Striking A Chord podcast, the strongest fit signal you can have short of a factory spec (his signature guitar actually ships stock with nickel RPS, not Cobalt).

If you tune to B standard / Drop A and your playing leans lead-fluid, this is the gauge. If your default is Drop G# or you primarily play heavy quad-tracked rhythm, step to 2730 instead.

View Ernie Ball 7-String Regular Slinky Cobalt (.010–.056) on Amazon

**7-string gauge guide:**7-string guitar string gauge guide **Richardson's own Drop G gauge:**7-String Power Slinky Cobalt (.011–.058, SKU 2729)**Stock heavier 7-string Cobalt:**7-String Slinky Cobalt (.010–.062, SKU 2730)**Voicing comparison:**Cobalt vs nickel Slinky: the voicing difference, measured **Cobalt range gauge guide:**Cobalt Slinky gauges explained **Artist rig:**Jason Richardson signature rig

Frequently asked questions

Which artists use Ernie Ball 7-String Regular Slinky Cobalt (.010–.056)?

Jason Richardson (Solo / ex-Born of Osiris) has cited Ernie Ball 7-String Regular Slinky Cobalt (.010–.056) in a sourced interview. See "These artists use this product" above for the full citation.

How is this different from the 2730 7-String Slinky Cobalt?

.056 vs .062 on the low B string. Same gauges on the top six strings (.010, .013, .017, .026, .036, .046). The .056 on the low B feels noticeably looser in B standard than .062, which some players prefer for faster picking and easier bending; .062 is preferred when tuning down to Drop A or Drop G# where the heavier string holds pitch better. Pick by tuning: 2728 for B standard / Drop A; 2730 for Drop G# and below.

Who plays 7-String Regular Slinky Cobalt?

Jason Richardson. Speaking on Ernie Ball's own Striking A Chord podcast, Richardson said: "I use Ernie Ball, primarily the Cobalts... gauge wise, for a Drop A, which is just standard tuning with the low string dropped a whole step, I use 10 to 56 for that." That's this exact set. He steps up one gauge, to the 2729 (.011–.058), for Drop G. Music Man's own spec sheet lists the guitar's factory-ship strings as nickel-wound RPS 10 Slinky, not Cobalt, so this is Richardson's personal/stage choice, not the stock factory string.

Will this set work for Drop G#?

Marginally. The .056 low string in Drop G# sits at about 18 pounds tension, on the soft end for hard rhythm work but playable for melodic and lead-driven material. For dedicated Drop G# rhythm, step to the 2730 (.062 low). For E standard with occasional Drop A, the 2728 is correct.

What's the cobalt voicing change like on a 7-string vs a 6-string?

More pronounced on the wound strings. The low B and the wound D, A, and E strings all benefit from the cobalt alloy's higher magnetic permeability, the low end reads tighter and louder through the same passive pickups (Fishman Fluence, BKP, EMG). On the plain strings the voicing change is subtler. Most 7-string players notice the cobalt voicing on the low end first.

Does Jason Richardson always play Cobalts?

Mostly, by his own account. On the Striking A Chord podcast he said: "I pretty much tend to use Cobalts. I'll use Paradigms every now and then, it just depends on what I have," citing string-ordering logistics rather than a tonal reason for the occasional switch. Cobalt is the set he names as his primary; Paradigm is the backup, not a documented choice for a specific tuning or session.

Are 7-string Cobalts noticeably louder than nickel 7-string Slinky?

About 2–3 dB through passive pickups, same as the 6-string Cobalt comparison. On a 7-string this matters more because the low strings have more harmonic content to begin with, the cobalt push helps them sit forward in a mix where the bass guitar is also competing for low-mid space.