[Amps] Amp Supply information

[Michael Almeter]

Hello All,    Being a newer ham than some (licensed in 2005), I don't know some of the history of companies that have come and gone. I've got an Amp Supply LK-500NTC, and have tried unsuccessfully to find information on what type of company Amp Supply was.     Can anyone tell me if they were known for producing quality amps? What their typical pricing on amplifiers were? Was it a working man's amp or something that those with deep pockets could only afford? Are they rare at all?    If anyone could direct me to maybe a QST or CQ advertisement that they might have taken out, I'd appreciate it. 
Thanks for all the help,
Mike Almeter

W4MJA