Really Inexpensive Systems That Sounded Great?

Get a book on vacuum tube design and go for SET in the preamplifier and amplifier. They are easy to design and to build. You can do the same with open baffle speaker designs using full range speakers that require very little power. 2A3 or 45 triodes can be heated with AC that is center tapped for the cathode to ground through a dropping resistor and polypropylene capacitors. Use polypropylene capacitors in a vacuum tube rectified power supply with Hammond chokes and transformers. 

There are $10,000 tube amplifiers that use the inferior electrolytic capacitors in the power supply and what you build will probably sound better.

@drbarney1 

Get a book on vacuum tube design and go for SET in the preamplifier and amplifier

Can you post a link?

KEF LS50 wireless - my system

KEF LS50W mk2 

both unbeatable at the price

kef engineers have packed in a bi-amp bi-dac dual mono amp set up in both that as a complete system is unbeatable at those price ranges. The mk1 is impressive, the mk2 moves it all on leaps with 380W/p/c of custom amplification - everything is designed to work with each other.

You just have instant ‘system synergy’ as every part is designed for the system

that the whole (the sound) is bigger than the sum of the parts

@daveselbow 

+1, that type of system could not be built for the cost of those speakers, maybe even for 2-3 times more.