Who are the most underground high-end companies


When I say underground I am talking about companies that fly below the radar. Not much talk about them on audio forums, little if no reviews, no formal advertising, rarely see their gear at shows.

taters
Quicksilver Audio,doesn’t advertise or loan for reviews. Outstanding gear!
Croft Acoustics is another one!
For speakers, you can't touch Tyler Acoustics. They will blow the doors off Vandersteen's best at about one-fourth the price.
If you're into tubes and ballsy amps, have a look at Tube Nirvana.net.
Don Sachs in Nelson, B.C. builds a preamp to die for and also rehabs the legendary HK Citations.
I own all these products, have no financial interest in their makers, but you can save a ton of money. Don't look for their ads in the slick magazines. These are all hand-built in one- or two-man shops, for the pure joy of it.