The biggest difference between the Modi and the Bifrost is 0.5V The Modi spits out 1.5V whereas the Bifrost can spit out 2V, so there will be an extra 2.5dB available. How that extra 0.5V pushes your tubes, I don't know. The other major difference between Modi and Bifrost is superior SPDIF implementation on the Bifrost. I don't listen to SPDIF on the Modi because it doesn't exist Like M-13 said, the Modi does a pretty good job at what it's designed for and 80% is probably close---it should actually be more like 75% ( 1.5V / 2V ). Cheers!