Hi Don, As a fellow owner of GH's, I have heard them with a number of different amps. IMHO, GH's don't really work well with Single ended low power amps. As you state, the GH's are 87db efficient, which is a bit of a tough deal for low power or flea power SE amps. I think the GH's need at least 50+ watts/ch.and more is a lot better.
You do not say how much power the amps you are considering put out, so I can only guess that since they are 300b's that they are putting out less power than 50 watts/ch.
You do not say how much power the amps you are considering put out, so I can only guess that since they are 300b's that they are putting out less power than 50 watts/ch.