Evidence was introduced yesterday into the financial misconduct hearing of Sen. Herman E. Talmadge (D-Ga.) indicating that Talmadge got $550 in unreported campaign contributions in 1974.

Carl Eardley, special counsel for the Senate Select Committee On Ethics, presented the committee with photocopies of two franked envelopes purportedly containing contributions of $500 and $50 from Georgia supporters of Talmadge for his 1974 campaign.

Eardley also showed the committee a memorandum bearing the initials of Talmadge's private secretary, Allyne Tisdale, The memo, addressed to the senator's former chief aide, Daniel Minchew, states: "DANIEL . . . For info.: These sums were given today to the SENATOR. None is reported in any form, of course. . . "

Tisdale, in testimony to the six-member committee, acknowledted that the note and initials were "similar to my style." But she denied ever writing the memorandum."This indicates I misrepresented campaign reports," Tisdale told the committee. "I'm sure that I never did that and that I was never ordered to do that."

The Senate committee is looking into five allegations of financial wrongdoing by Talmadge. One of the charges against the 23-year Senate veteran is that he improperly converted campaign contributions to his personal use.

Talmadge, who is attending the hearings but who has not yet indicated whether he will answer questions from the ethics panel, did not make any comment yesterday on Tisdale's testimony.

Talmadge's attorney, James Hamilton, has objected to the introduction of various documents, including the memo, because they were taken from Talmadge's files by Minchew in 1974 when he left his job as chief aide to the senator. But the Ethics Committee chairman, Adlai E. Stevenson III (D-Ill.), ruled that the records were admissible.

In the memorandum introduced by Eardley yesterday about the $550, there is also a typed notation next to Tisdale's initials that states: "As SENATOR said, this helps offset some of the campaign expenses which we are reluctant to pay from the Campaign A/C."

Eardley also introduced another exchange of memos, apparently between Tisdale and Minchew. According to Eardley, the memos concern $2,000 in travelers checks from another Talmadge campaign supporter, Howard Keck.

In a memo dated Aug. 20, 1974, Minchew referred to the contribution, nothing, "I will take care of the travelers check matter . . ."

A memo dated the next day was introduced by Eardley. In that memo, apparently from Tisdale to Minchew, she says "DANIEL . . . Please give SENATOR $500 and then lock in the cabinet under TV?"

In her testimony yesterday Tisdale denied ever seeing the travelers checks.However, Earley noted that in testimony to committee investigators last September, Tisdale did say the typing on theAug. 21, 1974, memo to "DANIEL. . . " appeared to be hers.

Tisdale said yesterday that she made the September 1978 statements because she had been "startled" when the memo was shown to her by committee investigators.

In other testimony yesterday, Tisdale said she first learned of discrepancies in Talmadge's office finances from Minchew in a June 14 memo last year. Later that same day, she recalled, Talmadge showed her another letter from Minchew indicating that some of the expense money had been siphoned off to Talmadge.

Tisdale said Talmadge was "shocked and amazed" by the Minchew letter. "He said he wanted me to read it," she recalled. "He said that it was unbelievable, that it was totally untrue." CAPTION: Picture 1, Sen. Herman E. Talmadge, left, talking with an aide during break in hearing. Photos by James K.W. Atherton-The Washington Post; Picture 2, ALLYNE TISDALE . . . denies writing memorandum