[bearded fiddler]

Thanks everyone. Richard, if I understand this right, you removed the switch for C1/C2 - C3/C4 - C5/C6 and replaced the caps by one 0.1 uF cap. Isn't this value higher than the combined value of the three original caps? Could you tell me something about the way capacitors raise or lower the bass roll-off frequency? Does one need more or less capacity for lowering the bass roll-off frequency? Excuse my ignorance but, although I can follow instructions and build kits, I have hardly any theoretical background. I'd like to read more about the basics, but I don't know where to begin. I bought Owen Bishop's Electronics A First Course, and it's ok, but I need something more focussed on valves and kit building, without getting swamped in mathematics and formulas. I bought a book on valves, but it's full of mind-boggling graphs. I hope you don't mind this rant.

Jan