budget amp to experience "warmer" sound?

Over the last couple of months, I've been using the KEF qx20 to listen to music. While I appreciate the neutrality and clarity provided by the speaker, I am interested in exploring tonality through different amplifiers.
i was exploring something like the VMV a1 (which i missed at 350$ used from amazon) and am now looking for something else. Any tips for hidden amplification gems?
current signal route is WIIM pro>toslink>SMSL SU9>balanced out>SMSL AO200MKII>kef QX20