Hybrid amplifiers consist of either of two combinations of tube and solid-state amplification. It may have a tube power amp fed by a solid-state preamp circuit, as in most original MusicMan amplifiers. Or alternatively, a tube preamplifier can feed a solid-state output stage, as in models from Kustom, Hartke, SWR, and Vox.
Preferred combinations
The latter combination avoids the need for an output transformer and easily manages modern output levels. It’s also the most popular and sensible way to make a hybrid amp. You can get basic tube distortion through the preamp and save the weight and expense of a heavy-duty tube power transformer. This also means the amp would be more reliable and have a classic solid-state high-frequency response. That sound was popular with metal guitarists in the 80s and 90s. Guitarists such as Gus G, Dimebag Darrell, Michael Amott, and Chuck Schuldiner have used hybrid amplifiers during part of their careers.
Standard adjustments on a hybrid, as with any amplifier, include tone and gain controls for adjusting the performance of the preamp tubes. Certain hybrid amplifier models offer boutique settings that are unique to their brand. These sorts of adjustments and effects are some of the biggest factors that separate hybrid amplifier heads since each manufacturer designs their amps with their own characteristic settings to experiment with.
It’s all about compromise
We could compare hybrid amplifiers to hybrid cars, it’s all about compromise. A hybrid car might not be as good as a gasoline car in some aspects and not as good as an electric in others. Although hybrid amps could certainly suit some guitarists, fewer and fewer of them are finding them appealing. They will prefer a classic tube amp or a modeling amp instead. Nonetheless, many of the newer hybrid amps are designed to sound tube-like and indeed come close. Companies like Crate, Marshall, Peavey, and Fender have produced them.
Preferences aside, with a hybrid amp you can get the distinctive tone of tubes together with the control and polish of a solid-state power section, making it a reasonable choice for many situations.
https://www.ultimate-guitar.com/articles/features/everything_you_need_to_know_about_solid_state_hybrids_and_modeling_amps-88251
