Margules is a high-end audio manufacturer hailing from Mexico with a U.S. distributor headquartered in Georgia. The have products for every part of the chain in your typical hi-fi system. They featured the U280-sc Black 1.3 Tube Class A stereo/mono amplifiers at the recent CAS 1028 hifi exhibition.
The amplifiers had a musical sound, not sounding tubey or mushy and had a good synergy with the company’s speakers.
The amps are extremely configurable, with the ability to run as stereo or monoblock amplifiers, and even knobs to adjust for the input impedance of your speakers. I don’t know of many 2 ohms speakers [the Soundlab Ultimate speakers got down to 1.7 ohms, I think, and the old Sonus Faber Extrema’s likewise, those crazy wonderful-sounding golden-age monitor speakers :-)] so these are often used as, if our experience with similar configurablity on the Lamm ML2 amplifiers is any guide, a way to tune your amplifier to have either more control and solidity or more ‘lightfootedness’.