The Triumph is equipped with a 1Ghz CPU - for all intents and purposes, you should only overclock by aprox. 25% of the stock value of the processor. The clock of the MSM8655 Snapdragon ranges between 1Ghz and 1,4Ghz, we can "assume" that the one in your phone is downclocked, but you have no guarantee that's true - it's only our assumption.
1,4Ghz * 125 / 100 = 1,75Ghz.
This is your *safe* overclock value. Anything over that may potentially damage your phone and you're doing it at your own peril... that said, the chances are slim - mobile phones are not supplying nearly enough power to "actually fry" - it's a rare occurrence. It may perform an emergency shutdown though - a tell-tale sign you "overdid it".
If our assumption is wrong, then...
1Ghz *125 / 100 = 1,25Ghz
Those values should keep it stable and cool while giving you a performance boost.
EDIT: just read online that 2Ghz "works" however it gets quite toasty when under stress, similarily to your 1,9Ghz overclock, surely. Meaning that "no, it won't explode on you".
