@runner You can use a Spectral pre amp with another brands amp but, not vice versa.
Personally, I wouldn’t risk voiding a warranty or a service issue. If you have a problem with those requirements or using MIT Cables. I wouldn’t even bother with Spectral. Spectral is really designed as a system. Pre+Amp+MIT Cables
As others have stated. There are plenty of other great brands out there to try.
@ebm Not over priced garbage. Under priced compared to high end solid state from Europe; in specific Switzerland (Soulution, CH, Dartzel).
It may not be your cup of tea but, please Mcintosh isn’t in the same league as Spectral. Current and modern Mcintosh gear although nice is midfi compared to the current Spectral stuff.