BY ISSUING a subpoena just days before the pre-election campaign-finance reports are due, the city's Board of Ethics has shown that tight deadlines won't dissuade it from seeking out as much as it can about those anti -Tom Knox television ads.

The Ethics Board issued a subpoena Monday to Alex Z. Talmadge Jr., a former city commissioner and executive director of the "527" Economic Justice Coalition for Truth committee.

Mayoral candidates and independent committees, such as 527s, must meet tomorrow's filing deadline for campaign contributions received up to April 30. But the 527s won't have to disclose any additional contributions, including those from big donors, until 30 days after the primary. Too late to know who's really behind the ads, or if they are truly independent from a specific campaign. (Talmadge has been a Brady supporter.)

These 527 committees, named after an IRS law, are tax-exempt groups that can raise unlimited campaign money, and are used to help a candidate, often with negative ads.

The Ethics Board's action is yet another sign that things have changed in this city's political campaign culture. *