laptop headphone socket out to amps

I'm very new to computer audio and have a minimalist system with a passive preamp for volume control of vinyl and cdp, but was cinsidering a direct connection for digital. Has anybody connected the headphone socket of a laptop via a Y-cable directly to their amps, using the laptop's D/A converter and volume control? Specifically, is there an advantage in sound quality when using the computer's volume control and avioding the passive preamp and additional interconnect? Also, would CDs ripped to lossless with this configuration sound better than my Rega CDp? Thanks.
i do it all the time.....yes,output of headphone to input/aux to intergrated/amp....make sure you start with all the volumes down and upgrade the volume gradually until you get a balance between computer and amp. I use it to listen to internet radio, other services. I also use it to use as a program for my cds recorded on computer, i have not started to buy a to analogue to amp which i know would be better, but to answer your question from one man's opinion, because you are going to get all kinds of answers, my cd player still sounds better to me with the dac in by player....if you buy a real good dac and use it from computer i am sure it will sound very good. I still use cd player because it still sounds the best to me...
If you have a Macbook, the headphone jack outputs an optical signal as well.

You just need to get a mini-toslink (laptop end) to toslink cable.

I use a VanDenHul optocoupler.
And no, most likely not. Your CDP would sound better, but try it and see..

I don't like lossless. I swear it sounds flat and compressed. I use bit for bit AIFF, and if I'm worried about hardrive space or it's overproduced dance/lounge type stuff, I'd rather use 320 kbps MP3 format. About a fourth the size of lossless and I think it sounds better.
Check out Audiomagus for cheap DAC's.They have the KingRex which has T amp for sens speakers and built in DAC.But you can get one for $89 that is better than one on sound card.Also check out APE MP3 format as alternative to FLAC just to know what's out there.