This is from the Response Audio website and should answer your inquiries.
The Musica Bella Ibrido is a custom built to order hybrid amplifier. Utilizing the Seque single tube buffer stage, it provides a high input impedance of over 800K ohms before feeding a 125/250 watt or 300/600 watt Class D amplifier module. The amplifier module is a custom OEM design by Class D Audio. The input stage is based on a single 6922/6DJ8 vacuum tube. Why a tube stage? Simple. Besides the reasons mentioned below in "Development", having a tube input stage provides a degree of warmth and smoothness that many audiophiles said Class D amplification needs. The Seque input stage does just that, it smoothes out the edginess very often associated with this type of amplification. If you are looking for a sterile, dry "audiophilish" sound or a syrupy lush tube sound, the Ibrido is not for you. The power supply of the tube input stage utilizes 2 separate transformers. A dedicated transformer for the B+ supply and a separate, high current transformer for the regulated DC supply feeding the tube filaments. A large, high current Toroidal transformer and enhanced power supply is used for the amplifier stage allowing the Ibrido to provide exceptional speed and dynamics. There is a total of 3 high current toroidal transformers used in the Ibrido.
Thanks for looking.
--Bob