No videos as far as I can find. You can read this long thread if you want. However, the opinions seem all over the place and all of these people are using the LYR or something that doesn't already have JFET:
https://www.head-fi.org/threads/schi...ssions.778326/
There is a statement in there that the LISST definitely warm/heat up, but not as much as tubes. So, a couple things could be happening:
1. The LISST is regulating down the tube high voltage (i.e. 200+ volts) to a more solid state level such as 15-30 volts and generating heat as a byproduct.
2. The LISST MOSFET circuit is running in Class A mode, which generates more heat.
Or it could be both of these. Schiit indicates the LISST are MOSFET circuits, as oppose to JFET that is the solid-state circuit in the Freya. So, it's really difficult to tell if the LISST is going to be any different than the built-in JFET.
Honestly, I think the JFET mode sounds somewhat flat and sterile when compared to good tubes (the Schiit stock tubes are not included). You could always try the LISST, but at $99 a pair, it's an experiment that may or may not be better than stock JFET.
If it were me, I would be going after the PSVANE CV181-TII, even though they are a lot more expensive.