My name spelled differently in my new passport but pronunciation is the same. Can I use my old US visa?

If you have an official document showing the change of name, you're all set; just bring that with you. But I suspect that this isn't the case, and the spelling changed only because of the passport office's transliteration policies. The rest of this answer assumes that to be the case.

I suspect that US immigration officers won't mind the change, but an airline is more likely to take exception it. The airline could be fined a few thousand dollars if the US finds that they brought you to the US without proper documents.

Thus, you need to determine not only whether the US will accept the new spelling, but whether the airline will believe that the US will accept it. It's safer to get a new visa.

If you want to avoid the expense and trouble of getting a new visa, you can try to get in touch with CBP using the information on the contact page. If you can get something from them in writing that the change in spelling is acceptable, then you might be able to convince your airline to let you board. But I don't think I would risk it.

Another option might be to get a document from the passport office explaining the change in transliteration policy or whatever other administrative reason there may have been for the change. It would probably be best if the document says explicitly that the two passports were issued to the same person. From what I've heard of Indian bureaucracy, I suspect that might be difficult or impossible, but if you can manage such a document it should serve the same function as a change of name document would, allowing you to avoid getting a new visa.