One note of caution about the philaudio tube amp plugin; I played around with it for a while, and it did a really good job of giving a tube sound, and generally worked pretty well with one exception.
It has the circuit path of the tube amp laid out in the VST window, and what's really neat about it is that you can adjust, say, the resistor values to get a different sounding tube amp. That's a really neat customization feature for a tube hobbyist.
However, do not (I can't stress enough), DO NOT attempt to alter the resistor or other component values while music is playing. I thought it would be neat to demo different circuit values on an A/B basis (while music was playing), and while editing the resistor values I deleted one value in order to type in a new number. Rather than latching off while there was no value there (or failing gracefully), the VST plugin produced the single loudest noise (a sharp CRACK) I've ever heard from my speakers, and then was cut off a split second later when JRiver's fault state caught it and turned everything off.
It's one of a very few times I've ever managed to get JRiver into the "PROTECT" mode where I had to restart JRiver to restart playback, and thankfully nothing was damaged (ears or equipment). But it scared me enough that I stopped using the plugin. Other than that it worked a treat