anyone got/used pro ject dock box fi

Firstly, why don't you use Airplay (since your Marantz has it).  You can transmit music from your iPhone/iPod Touch/iPad without having a dock.

Secondly, haven't tried the Pro-ject but I tested a pre-production Cambridge id100 with very good results.  Note that it only has a digital output so would have to go into the optical digital in on the Marantz (ie it wouldn't work with anything else that only has analogue inputs).

It's possible the OP is using an iPod Classic or Nano rather than a Touch (or iPhone).

If so, I would just use the little iPod support that comes in the Marantz box and plug the iPod into the front of the Marantz. (No cost at all).  I don't see the benefit of spending £150 on a dock when it can be plugged straight into the Marantz's own DAC this way.

Plus the Marantz only has AirPlay if it is downloaded for £39. It doesn't come as standard.

Good point, well made.

Or you could always download the iMediashare app for free, rather than get Airplay. Works with the wifi enabled iThings, as well as android phones. It streams to the Denon RC-DN7, so I'd imagine it would work with the CR603, as long as it's networked, obviously.

thanks for the advice.btw i do have a classic ipod and have used the marantz ipod connection but found that when i have played tracks from a playlist then remove the ipod to go out then replace it,it resets losing the track i was playing i find this really annoying and frustrating,likewise i find the media streaming very slow as i have over 90gig to scroll through.thinking of selling it and getting an intergrated amp as i don't use the tuner or the cd much

I have the dockbox vi. That is 'variable' rather than 'fixed', so it could be the basis of, say, a very simple headphone setup. I only got the vi as the shop I bought from had sold out of the fi in black so gave me the vi for the same price.

It's a decent bit of kit, good build quality and so on. SQ is fine but relies on the iPod's internal DAC. If I were buying now at this price I would get the pure i-20 (see WHF review). It bypasses the iPod's DAC and also has a digital output so you can upgrade with an external DAC at a later date.