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Chord · Ab Dominant 7♯5

A75 Chord

A75 is Ab, C, E and Gbwhole-tone derived; very tense.

Hear it

A75 on every instrument

The same 4 notes, 2 sets of hands. Open a diagram for alternate shapes, audio and the mistakes to avoid.

×4fr14123EADGBE
Guitar1 voicing
CDEFGAB
Piano3 voicings

What A75 is made of

Ab Dominant 7♯5 (Ab dominant 7♯5) is built from the notes Ab, C, E, Gb, with the interval pattern 1, 3, #5, b7. A common dominant 7♯5 chord across many styles.

Stack 1, 3, #5 and b7 on a root of A and you get Ab, C, E and Gb. That interval recipe is what makes the chord a seventh sharp five chord — move the same shape to another root and the character travels with it, which is why C75 sounds like a transposed A75.

Dominant 7♯5: Whole-tone derived; very tense.

Spelling: the notes above are written the way a score would write them, not simplified to the nearest piano key. That is why this chord is spelled with A rather than its enharmonic equivalent.

Keys that contain A75

No major or natural-minor key contains all 4 of these notes — this one gets borrowed.

Chords like this one sit outside the diatonic set — they arrive as secondary dominants, borrowed chords or passing harmony. Browse every key to see which progressions pull it in.

Other chords on A

Same root, different colour.

The same seventh sharp five shape, moved

The identical interval recipe, built on other roots.

Questions people ask about Ab7#5

What notes are in the Ab7#5 chord?
Ab7#5 is made of Ab, C, E and Gb — the 1, 3, #5 and b7 degrees of a seventh sharp five chord built on Ab.
What keys use the Ab7#5 chord?
No major or natural-minor key contains all 4 notes of Ab7#5. Chords like this arrive as borrowed harmony — secondary dominants, harmonic-minor colour, or chromatic passing chords — rather than as one of a key's native chords.
How do you play Ab7#5 on guitar and piano?
This page shows Ab7#5 on guitar and piano — 4 voicings in total. Each diagram links to the full instrument page with alternate shapes, audio and common mistakes.
Is Ab7#5 the same as G#7#5?
Yes. Ab7#5 and G#7#5 are enharmonic — identical pitches written two different ways. Which spelling you use depends on the key you are in; Ab7#5 is the spelling this site treats as canonical.

Learn the theory behind it

Why A75 behaves the way it does — the guides that explain the chord instead of just spelling it.

Borrowed Chords and Modal Mixture — Stealing from Parallel KeysThe raised fifth comes from outside the key. This is where chords like it are borrowed from.7 min readFunctional Harmony: Three Roles, One EngineThat sharpened fifth is a pull toward the next chord — here is the mechanism.6 min readIntervals — The Only Music Theory You Actually NeedTwo stacked major thirds, and the symmetry that makes it feel homeless.5 min read