I just purchased a set of mono amps which I think are an early version of the SEX amps. It uses two 6 dns7s per amp and I believe the output is approx. 4 watts. I am looking for a set of schematics for these amps,so I can further understand them. would it be helpful to purchase a set of current SEX manuals to gain the info on this mono version. They of course have no headphone outputs. They work perfectly now. Any information would be appreciated .