Everytime people see I buy a vampiric scepter they just rage and say im trolling. But no matter how much ppl say Sona is just a support Champ, they can´t be more wrong. With Ad sona you will be able to support (all auras still work the same) plus you can still heal, haste, stun and make all that "support" stuff. Ap scales poorly on sona and if she is caught alone she dies. But what if you could fight back? pwn? become legendary!? It IS possible with this build. BUT you will need previous experience with AP sona AND you need to be familiarize with her passive, her secret weapon.

PROS:

Heavy burst damage
Counters harrassment from enemy easily
Farming expert
Can easily 1vs1
Great escape and chasing mechanism
4 support Auras (Yes, 4)
AoE Stun, Heals, Haste, Slow, Reduce enemy's Damage Output
Underestimated by enemy

CONS:
Vulnerable to heavy burst damage (such as Leblanc's combo or Talon's)
Mana Issues
Global CD after using a spell
Hymn of Valour hits nearby targets so if enemy minions are around (closer than your enemy), the bolt wont hit your enemy champ, make sure to chase beyond minion wave or wait till there are no minions around.
Vulnerable to Silences, Snares and Stuns

Lets check Sona's Passive "Power Chord":(Innate): After casting 3 spells, Sona's next attack deals extra 14 + (9 x level) magic damage. This enhanced attack has an additional effect depending on which spell was cast last.

So after 3 spell casts, she unleashes a powerfull bolt of sound. But if you have it ready while playing Hymn of Valur you are ready to use the deadly power of Staccato (double the damage of power chord)

If that bolt of sound is activated after your Hymn of Valour + Trinity Force + Your Ad stats you will do massive damage.

Her deadliest combo is: Hymn of Valour + Staccato and trinity's passive + Crescendo + Ignite + Basic attacks

With this build, you will have massive attack speed and lifesteal, so by doing this you are restoring health continously, plus you can heal with your W, then launch a E (preparing another powerchord) and end it with our Q + Stacato and finish it.

I have 1vs1 Olaf (tanky), Garen, Wukong, Tryndamere and many other scary champs and WON. (with tryndamer you must use ignite for last and flash away, if u dont have flash then you proably get killed by his undying rage.

*Akali is hard to kill, because of her invisibility and burst damage, but can die easily if get's trapped by Crescendo and if has her invistibility on cd.

Early Game:

Vampiric Scepter: Combined with your attack speed, and heals you are pretty hard to kill
Berserker Greaves: Hit and recover faster!
Sheen: deadly with Stacatto

Mid Game

BF Sword: Great damage that goes well with your passive, lifesteal and attack speed
Starks Fervor: This is your 4th aura (attack speed, lifesteal and health regen for evryone!)
Trinity Force: One of your main Items for damage output.

Late Game
Infinity Edge: U are ready to 1vs1
Frozen Mallet: U are ready to 1vs1 on heavy champs like Olaf or Renekton
Optional Item:

Optional Item:

If there are lots of Ad Carries go for Thornmail
If they have lots of burst or fed enemies Guardian Angel
If its heavy Ap Team, Banshee Vail
If you just want to end it fast Phantom Dancer for heavy Crits and Tower smashing
If its a heavy tank team Black Cleaver


Irreplacable Items: Trinity, Starks

At the spawning pool, start with a Vampiric Scepter. With the lifesteal plus the 38% Attack Speed of your runes (you have to buy these runes) plus Masteries and you just have to hit minions and auto-recover. This tricks counters harrasment from enemy very easily, so Cassio's Miasma or Teemo's Posion will not be a problem. You need Sheen and Berserker Greaves next. Rush BG if you want to play more defensive (to evade attacks and recover with AS + Lifesteal) or rush Sheen for increasing in great proportion your damage output.

MID LANE
Sona can pwn mid lane. I have won over Anivia, Malzahar, Lux, Karthus, Morgana, Caitlyn, Ryze, Vladimir... and the list goes on.

SIDE LANES
You need a good lane partner, and remember you are not full "support" so your mana must be saved for the right moment and you cant afford wasting it on a noob team member getting harrassed for being careless.