I am using a Ten-Tec Hercules 2 on my 2nd radio which I purchased in 1990. The fan is a little noisy, but it still puts out it’s full 600w with no problems. I am using an Acom 1000 on my 1st radio which I have had for around 4 years, no problems with that either, and it will take an SWR of 4 to 1 before it reminds me !! 73 Steve, ZC4Li.