Well well well, time to dust off the ol' thinking cap and commence with a comparison for things I dont even own.
So here is YOUR chance to chime in on ideas, thoughts, comments or reviews of the following products. Anything worth adding I will post here, so you dont have to scroll thru the entire thread.
These are mostly for Mac Car users who wish to use the optical/USB/Firewire of the Mac Mini for their sound, as opposed to the line-out. These are all intended for audio recording, and not so much for actual audio passthrough like a pre-amp, but they can be treated as such.
converts between optical and coax S/PDIF
serves as a repeater to extend cable runs
TOSlink optical and coaxial digital inputs
TOSlink optical and coaxial digital outputs always active
transformer-isolated RCA jacks prevent system ground loops
Comments: cheap and small, takes optical from Mac Mini and converts to RCA for direct amp hookup. Needs external power source 9v
The CO2 is a compact and rugged digital audio tool that converts S/PDIF signals from optical to coax and from coax to optical. Its 2-in, 2-out design allows the CO2 to operate as a full-duplex, bi-directional converter, or as a half-duplex converter with “thru” port—allowing it to work as both a converter and a repeater. The CO2 is also affordable enough that it’s easy to add several if needed.
M-Audio Audiophile USB
2 analog line in pairs
2 analog line outs w/ level knob
S/PDIF digital I/O w/ PCM, AC-3 and DTS support
Comments: USB, optical and RCA inputs/outputs. un-needed MIDI and 1/4" jacks, unless you want a mobile recording studio. AC powered. External volume knob.
Audiophile USB is a compact audio and MIDI interface that builds on the success of our popular Audiophile 2496. AC-powered components allow Audiophile USB to deliver some of the best fidelity, frequency response, dynamic range and noise specs available in a USB interface. You also get digital I/O for pristine transfers, as well as the ability to pass AC-3 and DTS surround sound signals.
M-Audio - FireWire Audiophile 4/6
4 x 6 24-bit/96kHz I/O
S/PDIF digital I/O w/ PCM, AC-3, and DTS support
flexible software-controlled mixing
momentary A/B source monitoring switch
1 x 1 16-channel MIDI I/O
FireWire Audiophile is a compact, FireWire-compatible audio/MIDI interface that takes the legacy of M-Audio’s award-winning Audiophile line to the next level. 4 x 6 audio I/O combines with powerful on-board mixing in a mobile package that’s perfect for live performance, home recording, and digital DJ work. You also get zero-latency hardware direct monitoring, ultra-low latency ASIO software direct monitoring, and 1 x 1 MIDI I/O. FireWire Audiophile even has AC-3 and DTS passthrough for surround sound playback.
Comments: external volume knob software adjustable, Firewire powered, un-needed MIDI I/O, optical and RCA inputs, FOUR RCA outputs
Edirol UA-1EX USB Audio Interface
Up to 24-bit/96 kHz audio quality
ASIO 2.0 (Win/Mac), WDM (Win2000/XP), CoreAudio (Mac OS X) compatibility
Zero latency, direct monitoring
USB powered, AC adaptor not required
RCA pin (L/R) in & out
1/8" phone type S/PDIF optical in & out
1/8" headphone jack and independent volume control
Audio I/O signal indicators
Microphone input port for plug-in powered electret condenser type (stereo)
Input volume control
Sampling rate switch (32/44.1/48/96 kHz)
Supports both advanced and OS-standard drivers (Win/ Mac OS X), selected with ADVANCED DRIVER.
Comments: small, affordable, HIGH quality, external volume control