I suggest you clarify if you record via DI or mic'ing a speaker.
For mic'ing, a fan noise is a factor. For DI it is not. However, the S/N ratio of the DI could be a factor.
The V4B and PF50T sound similar to an SVT but not exactly the same. My understanding is the PF50T sounds like a 50W V4B. I own vintage SVTs and a PF50T. To my ears the PF50T is sweeter and more HiFi. The SVT has what I call a low mid push, which is simply a gentle wide-band bump centered around 400hz. The way these amp transition into drive is also a bit different. Weird thing is I dislike the way the PF50T drives when I listen solo, but it seems to work really well in the mix.
A draw back of the PF50T is they tend to require a humbuster mod. Some have said Ampeg covered the mod for them. Even with the mod, mine still has a small amount of hum but it's pretty low. The PF50T has two XLR outs. One is from the preamp and the other is taken of the output transformer. The amp has a built in dummy load, so it can be run without a speaker.
The PF20T has the two XLR outs and dummy loud like the PF50T. The tone stack is more basic, power is lower, and people say it's voiced a bit more like a B15. Some complain that it does not have enough gain to push either the preamp or output into driver territory. Using a bass with a hot output or a clean boost should easily overcome this if you want drive.
If you can find one, you might consider the Ashdown CTM30 Little Stubby. It does have a fan, but it's pretty quiet. I don't even hear it unless I put my ear next to the amp. Really nice range of tube tones and the tone stack is intuitive, which is not guaranteed with all Ashdowns

.
Here's a demo:
I agree with the video; the Little Stubby's Feedback control is really great. Many Trace Elliot and Ashdown tube amps have a mid shift control that you can toggle on and off. What the control does is shift the high pass cutoff of the bass control. If the bass control is turned all the way down, the mid shift has absolutely no effect on the tone. When the bass control is turned up, in one position it reaches up into the mids and in the other position it cuts off at a lower frequency. So the mid shift control basically determines the width of the amp's baked-in mid scoop.
The Feedback control seems to be a variable version of this mid shift control. It allows much more nuanced control over the sound than a pair of presets.