Just purchased a used pair of Paramount 300B amps. Hooked them up and there does not seem to be any issues with them. Couple of questions: what is the potentiometer for on each amp? And it seems like my current system with the Paramounts sounds kind of harsh and fatiguing. I have a Quickie pre hooked to the Paramounts that I have had for several years that I have used with no issues. Speakers are a pair of diy speakers at around 96db efficiency. They are single full range drivers in a ported cabinet. Prior to the Paramounts I was running a 1965 Fisher X-100 integrated that has been rebuilt. That Fisher setup sounds very very good. So, I am wondering if perhaps the Quickie is a bad match for the Paramounts or perhaps tubes?? The 300B tubes are Electro Harmonix and there is not a name on the 5670 tubes. I believe the Paramounts are stock builds. Looking for suggestions before I start spending money trying to smooth out the sound of these mono blocks.