[Mac Hammer Fan]

I have a G3 blue and White (G3 300). Is this sufficient for recording vinyl to cd or would a new Mac Mini gives better sound quality? (audio = analog)

TIA

[k_munic]

the sound quality depends on the converter, not on the computer/software
your Mac has a "line-in", so, your turntable needs some kind of pre-amplification...

a MacMini has no line-in, you need an additional converter, from 50$, Griffin's iMic, to Ion's ITTUSB turntable with usb-connection for ~100$, up to $$$$ for some pro-boxes...

finally, "quality" depends on state of vinyls, quality of pre-amp and what kind of turntable/needle...

[OreoCookie]

The new Mac mini does have a line-in, the old G4-based Mac mini doesn't.

CPU-wise, you are fine, but I do think for decent quality, you might need an external AD converter. Some turntables have a pre-amp built into them, so you might not need to buy one.

[Mac Hammer Fan]

I was planning to connect the B&O turntable to a pre-amplifier of Onkyo and connect this line-out to the G3 B&W.