Bluetooth

I wouldn't say most of the day but a good chunk of the day was spent trying to fit a little bluetooth module into this old amp. In most cases, the trouble with these things is that the circuitry is pretty finely balanced. There's power on the boards - in this case 25v coming out of the rectifier circuit in the picture - but if you add something, you change the current available elsewhere and in this one, you make a resistor start producing smoke. So, the answer is to tap into the mains, after the power switch and add another transformer and rectifier. Ebay will do you a nice little 3w LED driver that produces 12v to run the bluetooth.