Power Mac Digital Audio G4

Found my answer here:
http://www.apple-history.com/?page=gallery&model=g4da&performa=off&sort=date&ord er=ASC

[Would have hoped for a bit more functionality from a system that includes "digital audio" in its title.]

Announced in January 2001, the PowerMac G4 (Digital Audio) was the first speed increase for the PowerMac line in over a year. The G4 (Digital Audio) was so-named because of a new Built-in Amplifier, designed to drive USB speakers, along with the conventional minijack line output. The G4 (DA) included a number of architectural improvements, including a 133 MHz bus, 4 PCI slots, and a 1 GB/s main-memory bus. PCI throughput was enhanced by the removal of the PCI bridge (the main memory controller now communicated directly with the PCI bus.). Notably missing from the G4 (DA) was multiprocessing. With the exception of a dual-533 MHz BTO option from the Apple Store, all models included a single processor. This was, according to Steve Jobs, the only way Apple would be able to ship the 667 and 733 MHz models in sufficient quantities.