@8th-note Power amps that double their power with halving their impedance do NOT have to be hot and heavy. My Class A Westminster Labs REIs are small, 35 lbs., top case runs at room temperature except for the small indented metal screen, goes from 100 watts at 8 ohms to 800 watts at 1 ohm and costs $33,900 a pair. They replaced 125 watt Class A/B voltage regulated tube monoblocks and EAR Class A 70 watt tube amps (after 50 years with only tube amps). ASR recommendations are for inexpensive gear. Amir does not promote the best/better gear which is relatively expensive but not uber expensive like Westminster Labs.
@zlone I am keeping a tube pre-amp for the added warmth to the REIs which are just plain neutral and pass-through upstream source and component sound. Funny thing, the manufacturer/distributor of the Saunders Magatech who sold the company and is the sole non-Asian distributor for Westminister Labs products is the same Garry Leeds of Hear This.