For those of you who have never owned a low wattage cathode biased amp where you can change power tubes (and preamp tubes), or one with external bias pots, it would be an invaluable experience. I mentioned above regarding the variable sag control designed by Dave Zimmerman of Maven Peal. It was a feature included in all his designs, along with the wattage control (a very effective way to tame volume for home players). The Emery Sound amps (and there are plenty of others) are a tube switcher's dream.
However, there's still more to learn, and Cliff has given us experimentation tools far beyond what we could normally achieve with a soldering iron and spare parts. The increased sag is one more of those, even if it's unrealistic. I was unaware that the sag of a Plexi was that high. In fact, when I check the stock settings for many of the amp models, I realize how incomplete my education remains.
