Why not output the linout to the PC and then record your vinyl ?
It isn't digital after all
Well, despite the fact that recording through your PC is less expensive, it seems to me that it will never reach the quality that you can get using an external burner... because the burner is built on that purpose therefore you're pretty sure to have a high quality AD (analog-digital) converter and you'll be able to edit your disk content at will in a professional way, you should also consider that all the necessary connectors are already there...
The inside of a computer is huge source of "noise" (non isolated electronic components) therefore you're loosing a lot in terms of S/N (Signal/Noise) ratio... (after all a computer hasn't been built on that purpose)
That's the reason why I'm 100% sure that you'll reach a better quality recording using a stand alone unit... (even if you're cleaning or normalizing what you did record on your PC with Soundforge or Cubase)
The bad side of it is that it's not for free
Hey... but who said that you could get a Porsche for free
Could I suggest you to go an "real" Hifi store listen to one of those ?2000 belt drive turntable, connect your SL1200 and listen to the same record... I can garantee you that despite the fact that it isn't digital, you'll hear the difference... I know that DJ equipment isn't meant to be used as HiFi equipment... nevertheless I'm trying to reach the highest quality