Here are a few of the warmest sounding amps that I’ve owned that use toroidal transformers. Each had their strength and weaknesses. After trying these as well as many others i’ve settled on Audia Flight. Great amps if you can find one.
Primare i30
Vincent SV 237
Wells Audio Majestic
SimAudio i3.3/I5/340i
Older NAD amps
Kinki Studio EX M1
Best of luck in your search.