Upgrade speaker cables OR amp for Dynaudio C4's?

Your Plinius is probably worth $2500.00 and with the $1500.00 extra you have to spend I'd suggest the VTL 450, although the 750 would be much better still.

I know tubes are not what you're asking about, but the Dynaudio C-4 needs lots of juice and big tube amps compliment the design very well.

I don't think you know how much more texture and dynamics those speakers are capable of. If you have a chance to experiment I would go for it.

Far be it from me to contradict Mr. Porter, but I had both the JC-1s and the VTL 450s at the same time and I chose the JC-1s for a couple of reasons. First off the 450s put out a TON of heat. They also are chock full of tubes which mean problems with them probably. I like to leave my system on and ready to rock all the time and you can't really do that with the tubes. Most of all, I thought the JC-1s sounded better, a little smoother and better in the bass. The VTLs did have the tube magic though, and surprisingly were brighter sounding overall.

I would go for a new amp. Those speakers need some juice and if you've not got a chance to hear some high powered amps you are in for a treat. After fooling with amps of all different power ratings I don't think I'd ever go back to anything below say 300 watts.

First off the pro 9's are not very good...I just got rid of mine. I had the C4's as well and they demand alot of power. Third, try MIT spkr cables for realistic sound. If you like the current amp try the cables from The Cable Co...maybe Magnum M3 if you can fit it in your budget.