if his source has volume control" it will be the most transparent, dynamic, and least coloured way of getting the sound of the CDP/DAC to the poweramps.
Georgelofi, this is not really true, unless that source also has the ability to control the cable. If it does not a preamp may well be more transparent, more dynamic, wider bandwidth, etc. despite being an extra gain stage.
As you well know, many sources have compromised volume controls where the compromise allows for remote control. In fact this very reason is why many manufacturers do quite well selling line stages. You install the preamp, turn the volume control on the source all the way up, and use the volume control in the preamp *because it sounds better*: more bandwidth, resolution, transparency, etc.
Now a manufacturer of CDPs and the like could fix this problem but so far very few of them even recognize that its even possible to control the cable, let alone how to do it, so for the foreseeable future there will be a market for active line stages for precisely the kind of product you mentioned.
