Can someone tell me what's going on?

I used to run a pair of Audio Magic Clairvoyant Ql (xlr) ic between my Bat vk5i preamp and Bat vkd5 cdp and Nordost Quattro FIl (rca with xlr adapters) between the Bat preamp and Bel Canto amp. The sound was so so in terms of effects of the ic, nothing loss, nothing gain. When I switched the Quattro Fil to cdp and pre and Audio Magic to Pre and amp, everything changed. Bass becomes deeper and tighter, soundstage extended way beyond the side and rear walls, instruments are clearly separated with more body, and a greater sense of dynamic and mysicality is present. Unfortunately, I only have two cables and I'm still relatively new with all this stuff. I have heard mixed comments on where the greatest effect of the ic makes. My local dealer has told me between amp and pre, but I've also heard it's between source and pre. I'm thinking of replacing one of the two cables, because I want more of what I've heard. Can someone with more experience diagnose what happened. My thanks in advance.
You are on the right track. The IC from source to pre is the main deal. 'tis the one I would go with, big time, if I could only do one. Your next step is pre to amp, but you'll get the most bang for the buck and the most tympanic stimulation (as you've already experienced) from cdp to pre. case closed. Happy listening. peace, warren
Garbade in=garbage out.

Start at the beginning(source) with the 'best'cables.
I would agree with the previous posts. I recommend that you set up ICs in descending order starting with the source. I have experimented with my ICs the other way around and my system ALWAYS sounds better with my RSC Air 1 (my 'best' IC pair) between my CDP and pre.

Of course, it doesn't cost anything to switch 'em around and check it out, but I'll bet that I know what conclusion you will come to. ;)
The simple explanation is that the output impedance of your source is higher than the preamp output impedance. This is typically the case. Therefore, a low-capacitance IC will have a more profound effect from source to pre than from pre to amp.