I don't have any of these Darlingtons, so after some research I used a 2n5308, which seems to be a suitable replacement , though I had to twist the collector and base pins, according to the datasheet.
Thing is, it doesn't sound. I've used an audio probe and signal stops as soon as it hits the transistor. I even have de-twisted the pins but still nothing.
So, my problem is clear I think.........is there any other choice? can I use 2 transistors in a darlington configuration as a sub?