Hi there. I am having a bit of grief with this light-organ circuit. It works well, but only at a volume too loud for comfortable listening. I thought it would be fairly easy to improve the sensitivity, but that has not been the case. Aside from experimenting with the resistor values (which achieved nothing other than preventing it working at all) and adding an extra BC547 to make a darlington pair (which achieved nothing other than preventing it from working at all -again! ), Any suggestions? I'm sure it's simply a case of further amplifying the signal before sending it to the triac but my attempts thus far have failed miserably - and I would prefer to avoid op-amps for this circuit. Once I have got that sorted, I'll be adding another lamp and then a filter for different frequencies. Any suggestions are appreciated. Thanks. Mike Notes: The circuit did not work until I replaced C1 with a 10uF electro. The triacs suggested in the text aren't available here, I am using a SC141D. My Halogen transformer is rated for 150W so adding more lamps is not a problem, as long as I can drive the triacs.