no hard evidence on the name of Tamyrlin, I just read that Tamyrlin was rumored to be the name of the first channeler. i'm not sure where the thought originally came from, but i know its on the wheel of time wiki (i know, its a wiki.
) this is the only source i could find for it, but i myself, havent read that version of TEOTW:
Scott Mocklin tells us that the new glossary in To The Blight (vol. 2 of the YA version of TEOTW) has the following entry:
Ring of Tamyrlin (TAHM-ehr-lin): a legendary ring, believed mythical by most people, worn by the leader of the Aes Sedai during the Age of Legends. Stories about the Ring of Tamyrlin include that it was an angreal or sa'angreal or ter'angreal of immense power. It supposedly was named after the first person to learn how to tap into the Source and channel the One Power, and in some tales, was actually made by that man or woman. Despite what many Aes Sedai say, no one knows whether it was a man or a woman who first learned to channel. Some believe that the present title of Amyrlin is a corruption of Tamyrlin.
as far as what Lanfear says,
TITLE: Shadow Rising
CHAPTER: 9 - Decisions
"I cannot trust you fully, Lews Therin. Not yet." She [Lanfear] came closer, and he [Rand] considered simply seizing her. He was bigger and stronger by far - and blocked as he was, she could wrap him up with the Power like a kitten tangled in a ball of string.
"Not with that, certainly," she added, grimacing at Callandor. "There are only two more powerful that a man can use. One at least, I know, still exists. No, Lews Therin. I will not trust you yet with that." "Stop calling me that," he growled. "My name is Rand. Rand al'Thor."
she does say that a man can use, so that's why I think it's probably that ring. unless of course, you count being able to use both choedan kal by linking, but i tend to think she meant direct use by a man.