Cannot verify with confidence. 'Quadra' is a very generic name that could refer to multiple different performers (DJs, electronic artists, bands) across different regions. No specific performer by this name has clear, verifiable connections to The Old Post in South Burlington, VT in available data. The name alone is insufficient to distinguish which specific 'Quadra' was the performer listed. To verify, additional context needed: full name, time period of performance, or genre.