I removed the bright cap on my 1974 Marshall 50 watt JMP. It makes the amp volume very usable all the way from 0 - 10 and sounds smoother. I understand that varying the value of the bright cap will change how much of that 'bark' is added to the sound. So, what exactly is going on? Is it bleeding low end out of the circuit while boosting high end? With the bright cap in, this amp would go into overdrive very quickly. May be cool to make the cap switchable but is there a way to know what value would sound good? Is it just trial and error? Also, would different types of caps change the tone when used as a bright cap?