Whats a good matching preamp for Threshold S/300?

This was a rather cold and clinical sounding class A/B amp to my ears. And I sold them.

I would pair it with something very lush and warm. CJ Premier 3 or later, Eletrocompaniet, Meitner, Audible Illusions, MFA Magus (very good for the money). Pre '90's preamps would compliment the amp well. No need to spend a fortune.

The SP11 would be a little too towards the neutral for my taste.