Wide Band Gap Semiconductor Group, Kansas State University
Research on III-nitride wide band gap semiconductors, GaN, AlGaN, InGaN and related alloys.
http://www.phys.ksu.edu/area/GaNgroup/

Wide Band Gap Semiconductor Group at Kansas State University-Physics
Research focused on III-nitride wide band gap seminconductors, GaN, AlGaN, InGaN and related alloys.
http://www.phys.ksu.edu/area/semiconductor/gangroup/

Eagle
Eagle manufactures amplifier powered loudspeakers and electronics for studio monitoring and serious listeners. also scientific instrument and product design
http://www.eagle-audio.com/

Ophir RF
OPHIR RF designs and manufactures high power rf amplifiers, microwave amplifiers, linear amplifiers, solid state power amplifiers, wideband amplifiers and band-specific amplifiers and subsystems.
http://www.ophirrf.com

Broadband Power Technology
Broadband Power Technology
http://www.bptec.com/

Detroit Band Saw Works.
In business since 1987, providing Carbon, Bimetal and Carbide Bandsaw Blades, Coolant and Machinery to the Metalworking and Woodworking Industries.
http://www.detroitbandsaw.com

Matisse
Makes mono block and stereo amplifiers, pre-amplifiers, phono pre-amplifiers and cables.
http://www.signatureaudio.com/matisse.html

Advantech
Manufacturer of Solid State High Power Amplifiers (SSPA) and Low Noise Amplifiers (LNA) and associated redundancy equipment. Also manufactures broadband amplifiers and multiplexers.
http://www.advantech.ca/

TDI, Inc.
Technologies and Devices International, Inc.
http://www.tdii.com/

Conrad-Johnson
Wide range of (mostly tubed) amplifiers and preamplifiers.
http://www.conradjohnson.com/