Looking at the circuit between the PI and the power tubes of a typical EL34 power amp: On the anode of the "top" triode to the anode of the "bottom" triode on the schematic of my amp is a 250 pf capacitor. Although the rest of the circuit is based loosely on a JTM45 circuit, the JTM45 only has a 47 pf capacitor bridging across these same points. First, what is the technical name and function of this capacitor? Does the tone get affected by changing the value and how does the tone change depending on selection. My amp sounds like a "tuba" and JTM's I've heard sound like "trumpets" by comparison. I'm trying to get to the bottom of that issue. I need more forward mids and cut. Will changing this capacitor to JTM45 specs be worthwhile in this regard?