Woo Audio's Tubes
I think of Woo Audio as a manufacturer of fairly modestly-priced tube headphone amplifiers, so I was surprised to see in the Woo Audio exhibit something that was clearly more upscale. The WA5 is described as an "SET class-A transformer-coupled speaker and headphone amp." It's available as a base model at $3400, but the version with all upgrades (special tubes, etc.) brings the price up to $6400. The power output is 8Wpc, so your speakers had better have high sensitivity.