RF Amplifiers http://www.rfamplifiers.com
Offers a complete line of RF Amplifiers for NMR Applications in both low and high power versions from KHz to MHz. All amplifiers are broad banded.
Tomco Technologies http://www.tomco.com.au
RF amplifiers for NMR/MRI applications from 50kHz to 300MHz. They also carry other RF componenets, T/R switchers. and LNAs.