I grew up thinking of radio stations as magical places, and came to the realization rather late that they're often converted from something else and their use as a radio facility is sometimes just a fraction of their life. Some examples:
The KFI studios on Vermont Ave: Built for radio in 1936, as studios for both KFI and KECA (later to become KABC). KFI stayed there until 1975, when it moved to an office building on Ardmore. It's now part of the Clear Channel cluster in Burbank.
Apart from use of its original live auditorium for a scene in the film Lady Sings The Blues, KFI's Vermont studio sat for 28 years before the Los Angeles Unified School District tore it down. Great (and tragic) shots here:
http://www.geocities.com/christophermulrooney/criteria/id74.html
The KMPC studios at 9631 Wilshire Blvd. Home to the station's studios and transmitter in 1928. A few months later, the studios moved to the Home Beautiful magazine offices on Camden at Brighton. That building still stands. The transmitter and towers stayed on Wilshire until 1942, when they moved to Burbank Blvd. east of Coldwater.
KMPC's studios moved in 1944 to 5939 Sunset, where they stayed until 1968. That building is now the Spaghetti Factory restaurant.
Next stop: 5858 Sunset Blvd. Built originally as the first Warner Bros. Studios, the building had served as a bowling alley in the 40s and 50s after Warners moved to the First National lot in Burbank. KMPC left Sunset for the KABC/KLOS building on La Cienega in the late 90s. The building has been used most recently as offices for Tribune Broadcasting, but it was recently sold. Great shots from KMPC's history:
http://www.710kmpc.com/history.htm
KHJ's legendary 5515 Melrose studios were originally built for NBC radio. After NBC left, KHJ moved in for a while, then moved to the Don Lee studios on Vine Street. In the early 40s, Capitol Records came in and made 5515 its headquarters and studio, leaving only after completion of the Capitol Tower in the mid-50s. Frank Sinatra's legendary early 50s sides (along with those of Nat King Cole, Peggy Lee and dozens of others) were recorded there.
KHJ moved back in, staying until the 80s, when it moved out to the Venice Blvd. transmitter site. The building became office space for Channel 9. When 9 moved to Columbia Square, K-Earth moved from Venice Blvd. to Melrose for a couple of years, before its most recent move to Wilshire. I've been told 5515 is now office space for Paramount Pictures, though there's a listing of that building as "industrial space for rent" online.
The transmitter site on Venice still serves 930 AM, now Spanish, while Jack and KROQ use that studio space.
This is getting long (even by my standards

), so I'll just mention others like KFWB on Yucca (converted from a grocery store, now facing demolition), KNX at Columbia Square (of which part apparently will survive as an element of the new development going in there) and KRLA's studios at the Huntington Hotel (any trace of which has been obliterated by ownership changes and remodelings over the years).
---Michael Hagerty