Short answer - "punch" being a bit of a subjective term I'd say the V4B has more punch, the SVT more bottom. Longer answer - They use the same eq structure that is shared (with few exceptions) across the ampeg product range, a baxandall/james bass and treble arrangement and an active midrange control (where one is used). The difference between this and other tube heads is that the EQ is flat with the controls at noon where many other tube amps will be mid scooped with controls at noon and not capable of a mid boost from the EQ. How the rest of the amp behaves has a big impact on the total sound so it's not exactly fair to say an amp is scooped just because it uses a FMV style tone stack, some might be only lightly dipped, some might be hugely scooped, some power amps might even out the sound. The scoop might work perfectly for some and make others disappear in the mix. The cab and bass you choose can emphasize or cover up that kind of scoop. It's really a hard thing to pin down without sitting down with your bass and trying out a few amps. On the V4B vs SVT, to me the SVT seems to have a much bigger bottom at similar settings. Bass gear mag changed formats and I don't have the link to the frequency sweeps anymore, but the V4B is designed to be flat at noon and when they did a sweep on a 70s model versus a reissue they looked near identical. They did a similar sweep with Tom's early 70s SVT and found a low-mid hump with the controls at noon that they attributed to the power amp. Caveats of testing an old amp aside that seems about right when I've run my vintage V4 and SVT into the same cabs/with the same instruments. The V4 is flatter and more even, the SVT rounder on the bottom end in a way that fills the room, but a few tweaks of the controls and both get into the same range. That said, more than either amp I use one based on a Hiwatt DR201. A little more powerful than the V4B at 200 watts but lighter than the SVT by 5-10kg. Works well when using only a single 8 ohm speaker cab for small gigs. I'd say the V4B is my second most used amp.