Thanx Asmo, I'll go to Ratshack for the NE5532 if need be. A single
transistor with standard resistor values for bias and voltage supply
was not enough boost so I ended up using two. So yes, the opamp is a
tidier choice and may reduce the noise levels somewhat, so it's worth
the effort if I use the correct chip. This is what I aim to try. I
assume for power supply I now need a transformer with a bridge
rectifiier or a centre tapped secondary to run the op amp. No
problem......... There's room in the pedal box for a small tranny.