well going back and forth between the V1, and the C v3, the V1 is warmer more tube sounding? more thump, the V3 also has some good thump to it, but is a little more on the brighter side/airier, a bigger soundstage, with more detail, both are very very awesome though, I use the ZOv1 to add some thickness to the C v3 in my portable rig, and may I just say WOW! to that litle power house, I swear by that ZOv1 for any bass heads out there!!!!!
I wanted to get the PortaTube to do a side by side by side, it's a little on the priceier side, but I got a pretty good deal on the V1, and V3, the PortaTube is supposed to trump both these 2 by a margin or two? I'd love to hear that, and sell of the 2nd, and 3rd place tube amps? lol, yea right, like that would happen,
will be getting the V1 into a portable rig soon though!? lol,
right now I am using an iPod Classic 7th gen as a source>HP-P1>the V1, C V3>ASG-2s,