Question about Laptop as source

A DAC won't upscale the music files. All it does is convert a Digital signal to Analogue so that it can be played back on your amp speakers.

That being said I think music files from Itunes are fine at 256kbps.

so i still need a dac for this system to work

You do not 'need' a DAC, but one could be beneficial to the sound quality. You will though, need as a minimum, a mini jack to twin phono cable to connect your MB to the amplifier.

One of THESE. This is just an example mind you and not an endorsement of the cable itself.

I think so.

I have no experience with MACs so I am unsure on the connections they offer. I think the headphone socket doubles as an optical output but I may be wrong. This would need a DAC if you use the optical output.

As a temporary measure you could use analogue headphone output to connect to the amp.

Persoanlly I use an Onkyo dock which also doubles as a DAC. (although this is not necessary in my specific set up)

Thank you, for both replies. I have seen a bundle including a marantz cr-603, is this likely to work better?

http://www.hifix.co.uk/mini-systems/marantz/melody-media-m-cr603-black.html

Well that has a digital input so you could connect the MAC directly with a lead like THIS. (Assuming it has the socket I was referring to).

Would it sound better - I do not know how it would compare to the stereo amp although the CR-603 is highly regarded.

I'd say it would depend on your needs as to what constitues better. I suspect that the PM6004 and BX2 combination might fill a room with sound better, but the CR-603 combination would be more compact and perhaps versatile.

You already have a music player/streamer in the form of your MBP, so only need amplification and speakers, perhaps in the same box.

I use my macbook for music playback from my Itunes in Lossless via the mini toslink directly into the back of my hc amp (see below)  The sq is very good, use it for lengthy listening sessions, other times i use airplay.  If possible i would go down the dac route as the phono headphone cable is pretty basic.  I bought a standard optical cable(a long one so i can sit back in my seat and choose the music) and a mini toslink adapter from ebay which goes on the end and reduces the size of the plug.  Think it cost about £2...  

Hope this helps??