CV Database
Audience recording
PattonTrader quotes this date as "January 20, 1990 Philadelphia (PA)."
http://fnm.com/trade/ quotes this date as "Bayshore, NY".
http://web.stargate.net/soundgarden/articles/rocket_3-90.shtml
This article suggests Philly played after Boston, which would make it the 22nd.
http://www.voivodfan.com/tour-90.htm
Dates listed on tour t-shirt from eBay listing