The Museum Nusantara in Delft, the Netherlands, displays a more than 100 years old Javanese gamelan, Kyahi Paridjata.
Geert Jan van Oldenborgh and Paul van der Put (1st image of Performers) have made samples of most instruments using a large-membrane condensator microphone and CD recorder. Specifically, the sarons barung, demung and panerus (peking), slentem, bonang barung and panerus, kenongs, ketuk & kempyang, kempuls and gongs.
You can find the full resolution samples of gamelan Kyai Parijata here (16-bit 44.1kHz mono samples).
Visit the website for more information and links to download the samples (and alternate samples, mp3 and ogg versions).