Ive auditioned both the GamuT DI-150 and the Gryphon Diablo.
Two quite different amplifiers in my opinion.
The GamuT is characterized by stunning transparency and incredible treble extension, reproducing music with great focus, precision and impressive transient response. On the negative side of ledger for me at least I found the GamuT to be somewhat clinical and lean which in turn lead to an opinion that it was somewhat bass shy.
The Diablo has a highly poised, confident and unhurried view on music. Its bass is deep, powerful and solidly propulsive handling dynamic and rhythmic demands with ease. On the negative side of the ledger the Diablo does not offer class leading transparency, runs incredibly hot and in comparison to the GamuT looks butt ugly all in my humble opinion of course.
The sound of both amplifiers will be influenced by the source as both are relatively neutral with the GamuT being neutral/cool and the Diablo neutral/warm.