WRBK is owned by Jeff Sigmon. Jeff's father Curtis built and owned WYCL/York for years and years. WYCL was a top-drawer Top-40 station in its day.
WBT-FM (99.3), began life as WCMJ/Chester in 1969. WCMJ's studio/transmitter was housed in a mobile home, which was located south of Chester, just off Highway 321. In 1978, a very nice brick building was built on that site, which housed new studio gear and a new transmitter.
With that, WCMJ dropped country to become WDZK, which simulcasted WBZK (the former WYCL)/York, from 6:00AM 'till 6:00PM. After 6:00PM, WDZK continued identical programming from the Chester studios, which was then required by the FCC.
As K-99, the stations programmed an adult-oriented Top-40 format, closely resembling WYCL's successful offerings. Jeff Sigmon was K-99's program director. I did mornings at WYCL/WBZK prior to the initiation of the simulcast, as well as afterwards on K-99.
The move to the present 99.3 site happened in 1990, when the station first increased power from 3 to 6 kilowatts (a full "A"), then to a class C-3 in '92. Curtis Sigmon sold WDZK to Jefferson-Pilot in 1995, following which it became WBT-FM
All that to say that I'm not surprised that WRBK has a "spiffy" sound...it's a family tradition.