So I just got a brand new Airport Express
I'd like to be able to use it with my PMac G5 DP 1.8
Is this possible? I am not running any sort of airport card or anything like that
Can I use it in wired mode and use the airport express as a streamer for my sound system?
I assume your PMG5 is wired. And you may also have a WLAN-Router in your home-network.
a) You may use the Ethernet-option to connect the APX (AirPortExpress) to any LAN-socket and make the APX another WLAN-access-point.
b) Or you may use the APX anywhere in the range of your Routers WLAN-signal, receive the wifi signal and hook up any device to your home-network via the ethernet-socket.
(BTW both options also offer to connect a Printer via USB to the APX to use it as a network-printer ...)
Your will have to fiddle around with the Airport-utility and your routers-config-menue (depending on the routers-brand) to set up the right configuration for either of the options mentioned above and you'll have to switch the AirTunes-option in the APX's Airport-utility on.
Anyway ... both options let you connect any active speaker via Klinke-3,5mm-socket to the APX. As soon as the APX is connected to your home network, iTunes of any of your OSX, macOS or iOS devices will show up the APX as another option for sound-out. On iOS you may only chose either the iOS-device or the APX etc. as your speaker. With OSX / macOS you may choose multiple devices for sound-out and make one or more ATX-speaker-combination a kind of homebrew-SONOS system to recycle e.g. old Docking-stations etc.
(Funny - a few days ago I got two 2nd-hand elder APX and did set up such a system at our home and thought about writing a short review here in the PPC-forum. So here it is as a response to your thread ...
)
Here some pictures ...
PowerPC / Leopard
intel / ElCapitan