If you are referring to the currently produced Mk4 version of the Torii, you've probably already seen my comment about its gain in this recent thread, in which you also participated. FWIW I'll repeat it here, though:
In contrast, Stereophile measured the gain of your LM-518IA as being 38.6 db for an 8 ohm load connected to the 8 ohm tap, which is very typical for an integrated amp, and is vastly more gain than the Torii would provide.
Regards,
-- Al
Almarg 7-30-2018
In looking at the description and specs of the Torii IV I see one major potential issue. Assuming the specs on sensitivity and maximum power capability are accurate, it can be calculated that its gain is extremely low, even for a power amplifier much less one that could and would be used as an integrated amplifier. Specifically, I calculate a gain of about 17 db into 8 ohms, and even less into lower impedances. Typical power amp gains are in the mid to upper twenties, and typical integrated amp gains are in the mid to upper thirties.
If an active preamp providing substantial gain is not used ahead of this amp, with most vinyl and other analog sources the consequence of that will be that even with the volume control at max a substantial fraction of the amp’s power capability will not be able to be utilized. Probably well over half of that capability in most cases, and perhaps 3/4 of it or even more in many cases.
With digital sources that would be less of a concern, but I would still expect that without an active preamp there would be some recordings, especially some of those having wide dynamic range, for which the volume control would not be able to be turned up high enough to satisfy.
In contrast, Stereophile measured the gain of your LM-518IA as being 38.6 db for an 8 ohm load connected to the 8 ohm tap, which is very typical for an integrated amp, and is vastly more gain than the Torii would provide.
Regards,
-- Al