The Thonburi Rama Theater stands on Charansanitwong Road, near Soi 49 in the Thonburi section of town.
Believe it or not there are a handful of second-class (second-run) theaters still operating in Bangkok and beyond. The Thonburi Rama is a shining example. Like the BMC Daoanong, prices there are also only 40 baht per ticket and you get to see a double feature. The technology seemed pretty up-to-date, and like most of the old stand-alones, the screen and auditorium are massive, providing a pleasurable viewing experience. When I visited it in late May the Thonburi Rama was showing the same films being shown in the multiplexes.
Here's a little culturally relative observation: the sign of the Thonburi Rama reminds me of a motel down the Jersey shore, or maybe a bowling alley off the Boulevard in Northeast Philly.
Like the Thonburi Rama, most of Bangkok's second-class movie theaters were built during the movie theater boom years of the 1960's and 70's. The vast majority of them opened in what was then the outskirts of the city. Central Bangkok was the home of the first-class movie theaters. In truth, however, the only real difference between the first and second-class theaters was that the first-classes were first-run theaters, meaning they had access to the new releases first. Architecturally speaking, both types boasted of some pretty interesting designs.
Ironically, there are hardly any first-class stand-alones still operating in Bangkok. With the exception of the Apex theaters at Siam Square, they've all been torn down and replaced by the shopping-mall multiplexes. A regrettable state of affairs
If you have some free time, check out the Thonburi Rama. There aren't many stand-alone theaters that haven't taken to showing pornography, so it's my duty to give them a little plug up here when I find one, especially if they're up to par.
The Thonburi Rama is on Charansanitwong Road, just around the corner from Pata shopping mall and Major Pinklao - pretty easy to get to from the center of Bangkok.